Mercedes E350 DTC's

I have a 2010 Mercedes E350 4-matic.  At about 38,000 miles the "check engine" light came on intermittently.  I scanned it with a generic OBD scan tool and the Torque app.  It returned P0496 and P1077.  It started out setting these DTC's only once in a while, about 1,000 miles apart or more but it eventually happened more often.  I subscribed to the factory documentation and searched for the Mercedes DTC definitions but the documentation did  not show these 2 DTC's at all.  The generic definition is canister purge flow high.  I inspected the related hoses and found nothing wrong.  I searched forums and found some comments that people had fixed this with a new purge solenoid.  I removed and inspected my purge solenoid and found nothing wrong.  I checked to make sure it moved freely and sealed properly.  I noticed an adjustment on the top of the solenoid that was covered with silicone sealer.  I was able to poke the correct size allen wrench into the adjustment and adjust it.  The adjustment changed how far the valve opened when energized.  I ran the screw in a turn or 2.  I made sure the purge valve would still open but at a lower flow rate.  After driving the car for a while to let the monitors run the check engine light returned but this time 2 different codes were set: P0455 and P1085.  Neither of these were covered in the Mercedes documentation either so I checked the generic definition.  Now it said gross evaporative leak.  Interesting.  The DTC's changed so I know I was on the right track.  I turned the adjustment about 1/4 turn out (CCW) and drove the car again.  The MIL went out (so far).

Missing DTC's in the service information is a big industry problem.  I had this same issue on my Jaguar XJ8L.  What often happens is the controls are flashed with newer software which changes the DTC's but the documentation does not get updated.

It is also lame that Mercedes has 2 DTC's trip at the same time for a single detected issue.

I finally fixed the issue with a new gas cap.

Why I love Jaguar cars

Historically I was always a Ford fan.  I had all Fords until I acquired a BMW many years ago. My wife had always loved Jaguar cars.  They were beautiful, however, in the 1980's they were one of them most unreliable cars on the road.  British Layland pretty much destroyed the brand during this period and even today many people love the looks of the car but still remember the Jaguars of those years.

In 1989 Ford purchased Jaguar and began resurrecting it.  This took a long time as Jaguar was in bad shape at the time.  I bought my first Jaguar in 2000.  It was a 1994 XJ12.  We had a Ford Crown Victoria at the time and it had over 250k miles on it.  It was time to upgrade.  We looked at replacing it with another Crown Vic but when we saw the XJ12 for sale nearby we thought, what the heck.  We always wanted a Jag so now is the time.  I got the car cheap.  It was under $14k for a car that was originally over $70k.

This was not only my first Jaguar, but also my first (and only) V12 car.  This V12 had been upgraded under Ford ownership to fix all the oil leaks and other issues that had tarnished Jaguar.  We took this car on many trips and really liked it.  We eventually sold the car with 145k miles on it.

For a while I owned both the XJ12 and a 1998 XJR.  The XJR was a fantastic car for its day.  Very quick and fast.  Compared to the XJ12, and most other cars actually, it drove like a sports car.  I seriously considered taking this car to the track.

I still love the look of that XJR.  We sold this car with over 150k on it.

While the XJR was great in my book, my wife preferred a larger car with a smoother ride.  The XJR had firm suspension and wide tires for great handling.  She never used these features though.  So we bought a 2007 XJ8L.

In 2004 Jaguar created the X350 body style of the XJ which was all aluminum.  This reduced the cars weight considerably.  The whole car was redesigned and improved.  It was also larger.  The XJ8L is the long wheelbase version so it is even larger.  The back seat has enormous legroom.  It also has air ride suspension with active shocks.  Our 2007 was the last of the X350 (2008 was a slightly altered X351).

I also bought an X-Type.

The X-Type is really based on a Ford Mondeo. Being a Ford guy I am certainly good with that.  I will say though it is not like the XJ except in looks.  It rides like a Mondeo.  The X-Type and S-Type had heavy Ford influence and parts.  The XJ, XK, and the newer cars have very little in common with Ford.  Jaguar has always made their own V8 engines.  The new Jaguars now don't have any Ford parts.

So, why to we love these cars.  It is actually hard to explain to people.  Each time we were ready to replace our Jaguar, we drove many other cars and always came back to Jaguar.  They have a particular feel that is hard to describe.  The controls  are simple and intuitive.  The ride is really fantastic.  Not the boaty ride of years ago.  Firm yet compliant.  The car does not lean in corners yet it can soften up our nasty Illinois roads.  Acceleration is very good and smooth.  The XJR and XJ8L have a very pleasing exhaust note yet no drone.  People are amazed to hear the fuel economy this 2007 XJ8L gets.  I have done as good as 32 on the highway.  I always get 27 - 32 on the highway, and about 20-22 in town.  For a car this huge I feel very good about that.  The car just glides down the highway, even on terrible roads.  It is very controlled even at high speeds and the driver feels confident going fast.  The occupants are in a serene environment even when it is not so serene outside.

Jaguar has actually won or scored very well in several JD power's awards more recently. Both the quality awards and the APEAL awards.

I do all my own work on all my cars.  Jaguars are not that hard to work on.  

Why I Love Porsche

I was raised in a Ford family actually.  Growing up our family owned all For and Lincoln vehicles and I really liked them.  The vehicle I drove most after getting my license was a 1972 Ford Bronco.  My first car was a 1968 Ford Mustang and I worked for almost 15 years at a Ford dealer.  However, a few years after high school I began to notice Porsche.  Reading car magazine around this time there was always a Porsche doing something great.  I liked the 911 because it was so different from other cars.  The rear engine design has many advantages for making a car fast.

• The weight is already over the drive wheels for excellent traction
• The drive wheels are the rear wheels where it belongs for best acceleration
• On hard acceleration even more weight transfers to the drive wheels
• The flat engine design keeps the weight very low in the chassis for better handling
• The engine being so close to the rear axle helps reduce the moment of inertia when the car changes directions (turns)
• The car was simple and light.

I guess I was a closet Porsche fan from that point on.  It was not until 2004 that I would actually buy a Porsche, and it was not a 911.  Unfortunately Porsche's are rather expensive.  In my case, my first Porsche was replacing my 3rd car and it is a bit harder to justify a 3rd vehicle.  We had only 2 cars until 2000 when my in-laws gave us their 1984 BMW 318i so I was replacing a car I had acquired for free.  My budget at the time did not have room for a 911.  I found a 1987 944S locally so I drove it.  After a short drive I decided it belonged in my garage.  I owned that car for 10 years.  

Not long after I bought the 944S I joined the Porsche Club of America.  There was a fairly active local region, and the president of that region worked in the building next to where I worked.  We got to know each other.  One day I was complaining that their website was out of date so he appointed me webmaster.  Next thing you know I am on the board of the local region.  

I joined the PCA mostly to attend track days, also known as drivers education or DE.  I had heard about them and really wanted to go.  In high school, and for several years after, I would drag race occasionally at a small 1/4 mile track near my home in Washington State.  Drag racing is fun but you only get a few seconds of fun at a time.  I was ready for a road course.  My first DE was at Blackhawk Farms.  I was a Chicago Region PCA event for novices such as myself.  I had a blast and was hooked.  I attended a couple events a year for several years there at tracks within a few hours drive. 

In 2014 I bought a 2006 Cayman S.  That story is here.  My first track day in that car was a Putnam Park, my favorite track.  Every car brand has a unique feel.  Its hard to describe the feel of each brand, you just have to drive them.  Most people tend to get used to the feel of the brand they drive so other brands feel different.  I think this is much of what creates brand loyalty.  Porches definitely have a special feel to them.  Even the 944S had a special feel, even though it was a front engine inline 4 cylinder car.  The Boxster, Cayman, and 911 are very different than other cars though.  The car is so different than most other cars and you feel it as soon as you push the car.  Typical cars seem to complain when driven hard.  Tires squeal, the car leans and groans in corners, and the engine wheezes under full throttle.  Not the case in a Porsche.  They love it.  The harder you push them, the happier they are.  The engine sings to you as you approach red line at wide open throttle.  It sounds so good that I often hit the rev limiter before shifting.

As I mentioned above, the Boxster, Cayman, and 911 have a very unique layout which has many advantages.  The 911 is the most unique having the engine actually behind the rear axle.  The Boxster and Cayman are mid-engine which is a layout shared with nearly all supercars. The unique thing about the Boxster and Cayman is that they are not only mid-engine, but they use a flat 6 engine in the middle.  Most supercars are a V engine (V6, V8, V12, V16).  The flat engine is much better for weight distribution because it keeps its weight very low in the chassis.

Now the engine weight is not only in the middle of the car, towards the rear where the drive wheels are, but it is also down very low.  This makes it the best handling car you can get really.  It also make for fantastic stopping as the rear wheels are actually providing much of the stopping power unlike front engine cars.  When you look at the layout and features of the Boxster and Cayman, these cars are a bargain even at the fairly high prices they command.  There are not many low priced mid-engine performance cars out there.  If you go back a bit you could say things like the Pontiac Fiero and Toyota MR2 were also mid-engine and were cheaper.  This is true, but they were also cheaper in every way, not just less expensive.  The  modern Lotus cars are probably the closest and they are priced similar.  

Porsche cars are really made for track duty.  You can take any Porsche right from the showroom to a DE, have fun all weekend, and drive it home.  This is not true with most cars.  Usually the brakes just can't handle the repeated heavy braking of a track day.  They will fade or worse, boil the fluid and fail.  Most performance cars can handle it OK if you upgrade the brake pads and fluid.  I ran street pads at Putnam in the Cayman with no fade at all.  

While some may consider Porsche an exotic, they can really be driven daily too.  I would not put Porsche in the same group as Ferrari or Lamborghini for instance.  They cost far less to own and maintain than those cars.  They are also much more reliable.  Porsche has many JD Power quality and APEAL awards.  You often see Porsche's with well over 100k miles on them.  It is rare to find a Ferrari or Lamborghini with high miles.  I drive my Porsche to work every day when there is no salt on the road.  I used it for grocery shopping, runs to the hardware store, etc.  It is my daily driver.  Porsche does make real exotics though.  The 959, the Carerra GT, and the 918 for instance.  These cars often outperform those other exotics.  The 918 still has the track record at the Nurburgring Nordschleife.

While these cars are a joy to drive everywhere, you can't fully enjoy a Porsche just driving it on public roads.  You really need to spend some time driving one at speed on a real track.  Only then can you fully experience the difference.  

Everything in life is a trade-off decision. For many a car is simply a transportation appliance meant to move people and things from place to place.  They look at a car much like I look at a washing machine.  You find one that will do the job for as cheap as you can while maintaining reliability.  Many such as myself however, view cars much differently.  They are a thing of both visual and audible beauty.  They excite your senses.  The driver and car combine to make an athlete.  Those shopping for a transportation appliance generally look at these priorities.

• Miles per gallon
• Cupholders
• Utility
• Seating capacity
• Reliability
• Purchase cost
• Smooth ride

I have these priorities.

• Smiles per gallon
• Power and acceleration
• Handling
• Braking
• Lap times
• Aesthetics
• Feel and sound

I do not consider myself a badge snob.  I would be more than happy if everyone could own a Porsche.  Exclusivity is not something I am into at all.  Sadly some do buy Porsche for this reason alone and it tarnishes the brand a bit in my opinion.  People get the wrong impression of Porsche owners.  

How to start using a new Android device and get the best experience from it

There are many Android devices out there today.  This article will focus on tablets and phones.  Android is an operating system, similar to Windows or Linux.  However, Android does allow a significant amount of customization by the manufacturer who are creating an Android build for a device the sell.  Unfortunately device manufacturers can't seem to leave a good thing alone.  They put what is called "skins" on Android that make it look and act very differently.  Some of these include:

• Amazon Fire OS
• HTC Sense
• Samsung Touch Wiz

For the most part, these modified Android versions are much worse than the proper Android which leads to a poor user experience, crashing, delayed updates to new operating systems, and inconsistency between devices.  I have been an Android user since the very first Motorola Droid came out in 2009.  I also had one of the first official Android tablets the Motorola Xoom.  When I try to use a Samsung or LG device, I have a hard time finding things.  The settings are all different.  Too much just looks and works differently.  As an app developer, I have also run into many issues caused by the customs versions of Android.

In addition to the custom operating system, they also create their own custom apps for email, calendar, phone dialer, contacts, file backup, device backup, etc.  None of these work nearly as well as the Google apps.  In the case of devices branded and sold through a cellular provider (the vast majority) it gets even worse.  Far worse.  Now the cellular provider really pollutes the device with a bunch of really awful software like their own versions of device backup, app stores, file storage, etc.  This adds yet another layer of terrible software on top of terrible software that really hurts the user experience and makes updates drag on for eternity, if ever.

So, how do we make things better.

1. When you first get your new device make sure you log into it with your Gmail account that you create, preferably ahead of time.  Do not log into the cellular provider backup or file storage accounts.  Skip those steps.  Do not have the cellular store try to copy your contact in either.  They generally make a mess of it.  Their generic contact converters seem to always mess up copying fields from your current contacts.  If you have a non-smart phone you can use BitPIM to extract your old contacts.  Then upload them to Gmail using a PC and clean up any issues.  Use the PC to add new contacts as well.  Once you have your Gmail contacts correct, they can sync to the phone.  You can then manage them on the phone or the PC.
2. If your phone or tablet has a confusing home screen and interface, install Google Now Launcher right away.  I recently bought a Lenovo tablet and the first thing I noticed was the terrible home screen.  Installing Google Now Launcher made a huge difference.  
3. Disable and uninstall all the bloatware and terrible device manufacturer and cellular provider software that you don't want or is redundant with the Google apps like mail, calendar, backup, etc.   You do this by going to Android settings, finding "apps" in the list and selecting it.  This should list apps on the device.  Be careful to ensure you are seeing all apps, not just the ones you added.  You do this by scrolling to the right.  You will see the tabs change from "downloaded" to "running", to "all".  Make sure it is in then "all" tab.  Scroll down to the apps you don't want and select them one at a time.  For each app, click the "uninstall" button if it is available.  If "uninstall" is not available but "disable" is then disable.  
4. Now install the right apps.  I prefer all the Google apps for most things.  
1. Google Calendar
2. Google Maps
3. Google Drive and the related Docs and Sheets 
4. Google Photos
5. Gmail or Google Inbox
6. Google Hangouts
7. Google Translate
8. Google Play Music
9. Google Play Newsstand
10. Google Play Movies & TV
11. Google Play Books
12. Google text-to-speech
13. Google Camera
5. Now disconnect all the older bloatware apps and connect the Google apps instead.  Start with calendar.  The other calendars are mostly junk as you store much of your calendar locally and they often don't connect or sync correctly with Google calendar.  Open Google Calendar and make sure you are logged in and that the local calendar is not the default calendar.  Use your google calendar for all appointments.  This way everything in synchronized in the cloud and you can manage it both with a PC and the phone.  You can also easily connect to other calendars such as school, clubs, etc.

Another option of course is to just buy a Nexus device to begin with and all of this is already taken care of for you.  I prefer Motorola devices.  The newer (Google ownership and after) are much cleaner than most so it is as close to a Nexus you can get short of a Nexus.  Now you can get the Nexus 6 which is both Nexus and Motorola.  Motorola finally started bypassing the carries all together.  Now you can get the 2015 and up Moto-X and other models direct from Motorola, unlocked, and bloatware free.

One other issue with the user experience is push notifications.  I guess this is a personal thing but there are very few push notifications I want.  Nice thing about Android is you can block apps from pushing notifications to your notification bar, beyond just the settings in the app itself.  There are several apps I do block because they misuse it.  In order to block an app from notifying, go to settings, then apps, then select the app of interest.  This is the same place we were above to disable and uninstall.  This time though just un-check  "show notifications".  That app can no longer put stuff on the notification bar.  Great feature.  

I actually don't have Facebook app installed.  Facebook is the kind of app that abuses push notifications and it has other issues.  I do use Facebook however.  I just have a shortcut on my home page that is a bookmark to the website.  Most people cant even tell the difference.  My home screen button looks the same as the app.  When you click the shortcut the website loads a mobile optimized page that looks nearly identical to the app.  The beauty of this is that Facebook cannot run in the background chewing up battery and data, and it can't pester you. Chrome browser added the ability to do push notifications in web apps in 2015.  However, when you first load the page the web app will ask if you want push notifications.  You can say no here.  To add a web app to your home screen in Chrome (on Android or desktop) use the menu and click the "add to homescreen".

Believe it or not Microsoft of all companies have made some good Android apps and services lately.  Some of these may rival Google.  In some cases I have both.  I use both Google Drive and One Drive for instance.

I started using Waze for navigation.  It has a fantastic crowd sourced traffic data that is unrivaled.  It is also owned by Google by the way.

The new Google Photos includes free backup of all your photos (up to 16MP) and videos (up to 1080p).  That is the best deal out there.  They also have a PC app to back up everything from your PC too.  You do have the option to backup larger photos and videos but that will cost Drive space.  16MP and 1080p is very good size, and happens to be equal or larger than most phones will shoot anyway.

I use Hangouts for SMS, MMS, and Hangouts IM, voice calls, and video calls.  It works great and free all over the world (except China where nothing Google works).  When I travel in and outside the US I can connect WiFi at my hotel and call home for free.  Very nice.  I have all my messaging in one place too.  Skype will do about the same except for SMS/MMS so it is another good option.

I like both Google Play Newsstand and Google News & Weather.  I read the news on both these apps every day.  With Newsstand, you can even connect to subscribed papers and magazines.  I subscribe to the Wall Street Journal via Newsstand for instance.

Google Play Music is also a great app.  It lets me use my music library both in the cloud and on the device to create instant mixes.  This is great for long trips where you don't want all kinds of strange music you don't like from a Pandora or the like since you can have Google Music use only your music for the mix.  It also has ad free streaming if you want it.

I use My Tracks to track my bicycle rides.  The only issue I have with it is the calorie estimator.  So, I also use Cardio Trainer.  I run both apps at the same time on the same device.   The only issue is you can only connect your heart monitor to one of them at a time.

Porsche Cayman S grilles

I have a 2006 Porsche Cayman S.  From the factory there are no grilles for the radiators so they collect leaves, rocks, bugs, everything.  The stuff gets sucked in and has no way out.  This is an issue on the 987 (Cayman/Boxster) and 997 (911). The plastic bars in the openings are plenty big enough for all this trash to get in but not really big enough to get your hand in there to clean it out well.  If you push and struggle, you can reach some of the bigger stuff.  The only way to really clean it out is to remove the nose of the car.

There are aftermarket grilles available.  Most cost around $300.  Some pop on from the outside and others install behind.  After looking at some of these options I decided to just get stainless grille mesh from Amazon and make a set of grilles myself. The grille material comes in a 6" x 36" flat piece which was perfect to make these grilles.  I wanted very good airflow so I selected a mesh with at least 80% open area.  It cost $18.99.  My goal was to keep the larger debris out.

The nose of the car is not that hard to remove really.  However, it is not obvious how to do it either.  You need to read the manual.  There are a few options to get the manual.  You can go to www.nastf.org to get the factory service information for any 1996 or newer car or truck.  The manufacturer works with the government to determine pricing for subscriptions.  In Porsches case, they have a rather undesirable pricing scheme where you can buy $10 access or $100 access.  Of course the stuff you generally want in just over $10 it seems so you have to opt for the $100 access.  Instead, I thought I would give AllDATAdiy a try.  I think it was under $40 for a year of access.  I have used it many times now and while its not as good as the factory info, it works.  Basically there are screws in top, in the wheel wells, and along the bottom you can readily see.  Then there are 2 clips you access from under the front trunk area.  There is also a large wiring harness you disconnect behind the right headlight area and a washer hose behind the left headlight area.  From there you slide the whole thing forward.

Here are some photos showing the nose removed.

Nose removed showing the air ducts over the radiators and condensors

The nose off the car

Looking behond the nose of the car at the air openings

You can see the slot to the right of this headlight where the clips goes behind to hold the nose.

The electrical connector is in here, accessed from the wheel well above the radiator

I had already cleaned most the debris out when this photo was taken. You can still see the leaves packed above the condenser though.

New grille in place, held in with small black zip-ties

After removing the nose and air ducts I loosened the condensers and cleaned the debris from the radiators and condensers.  I also used compressed air to carefully blow back through the radiators and condensers to remove all the smaller debris and bugs while being careful not to bend any of the cooling fins.

Here is what it looks like now.

I actually wanted black grilles but I did not want to use metal that would rust.  Aluminum would have been either too weak or too bulky. I could have painted these grilles, which was my original plan, but I was concerned the paint would not bond well and if they chip you would see the bright stainless under it which would be much worse.  So, I left them unpainted stainless.  

GM P0101 MAF DTC

A friend had an interesting problem with his 2005 GM car.  The symptom was this: the car died while driving and would not restart.  He towed it to a shop where some repairs were made (fuel pump and filter replacement I think).  This car does have over 100k miles on it.  As he drove the car home it died again and would not restart.  He brought the car home and scanned for DTC's.  He got a P0101 which is a mass air flow (MAF) rationality fault.

At this point I need to provide some more details about how this fault works.  You can find the GM diagnostics specs here: https://service.gm.com/gmspo/mode6/ This is a very helpful website since it described the diagnostics strategies.  The way this DTC trips is a comparison between the MAF reading and a speed-density calculation done in the engine control which estimates MAF.  When the MAF deviates too far from the speed-density model, the MAF signal is deemed bad, the DTC is set, and the engine control reverts to this speed-density model to control the engine.

When the DTC was cleared the car would run fine until the DTC tripped again.  At that point, the engine would die and would not restart again until the P0101 was cleared again.  Rationality DTC's like this are tricky to get right.  The strategy did take a while to test and confirm the rationality fault before setting the DTC.  If the MAF was disconnected, the engine would die and not restart.

With these symptoms I suspected the problem was actually with an input to the speed-density model and not a problem with the MAF.  Further testing revealed that the manifold absolute pressure (MAP) reading showed 20kPa with the key ON, engine OFF.  We are at about 600ft above sea level here.  That reading should be around 100kPa.  He checked the circuit for wiring issues and determined the MAP sensor had failed in range.  Replacing the sensor corrected the problem.

While the DTC appeared to point to a MAF problem, the root cause was actually an in-range failure of the MAP sensor.  This is a great example of how DTC's do not report root causes.  They only report symptoms.  Smart technicians need to take this info and determine root cause.  It is NOT a matter of replacing the sensor the DTC relates to.  You must have a good understanding of engine controls including the fact it has a speed-density model that is used for this rationality check and how that speed density model works.

Maintaining your own car

I was a professional service technician (mechanic) at a Ford dealer for almost 15 years.  It was my first career.  I went to trade school in Arizona to learn my skills and focused on electrical and electronic systems, driveability, and air conditioning.  I did other repairs as well.  I have some of this experience documented on my website here: http://jimroal.com/repair.html.

I completed a BS in Mechanical Engineering and changed careers in 1998.  However, I still do all my own car maintenance.  I have owned several makes and models over the years.  You can see most of them here: http://jimroal.com/cars.htm.  The only things I take the car into a shop for are tires and alignment since these require machines I prefer not to invest in, although I have considered an inexpensive alignment machine.  I have also made small alignment adjustments at times.  I never buy new cars.  I prefer to let others take the depreciation and pick them up for much less just out of warranty.  I have also purchased cars that still have warranty remaining.  Car reliability follows what is called a "bath tub curve".  There is initial reliability issues early in the cars life.  After those get fixes, your reliability is at its best until wear out.

The sweet spot is somewhere between about 10k miles and 150k miles with modern cars that are well maintained.  I often drive my cars well over 150k miles.  I sold my Crown Victoria and Audi with over 250k miles on them.  I sold my XJR and XJ12 with around 150k miles on them.  Buying a new car means you have a higher probability of needing an unscheduled repair because of infant mortality.  You pay extra for that privilege.  Keeping a car too long means you need to replace parts as they wear out.

If you don't properly maintain your car however, you are asking for trouble.  If you use cheap service parts, you are also asking for trouble.

Engine Oil

I use only synthetic oil in everything I own including my lawn mower.  Once you understand just how superior synthetic oil is, you will never go back.  I saw the difference first hand in a 1982 Honda XR250 motorcycle.  This is an air cooled 4-stroke bike.  At the time I lived in Southeast Washington State where there were many sand dunes.  Soft sand really works a bikes engine hard. They get very hot.  I was using original equipment Honda oil in it.  After just 3 rides in the dunes, the oil would be noticeably thicker and very black.  I switched to synthetic (Mobil One) and I could now go 30 rides and it still looked good.  Huge difference.  After I saw that, I was convinced.  I also worked on many turbocharged engines when I was a mechanic.  I saw too many turbo failures caused by oil coking in the bearing.  Basically natural oil cannot handle heat.  Engines make heat.  So, rule #1: use only synthetic oils in all engines.

On cars that get driven at least 10k a year, and that 10k does not have excessive cold starts and very short trips in it, you can go 10k to 15k miles between oil changes if you use good synthetic oil.  I use Mobil One extended performance in most my cars.  My daily driver does get many short trips and cold operation so it gets changed much more often.  Long trips are much easier on the oil so if I take a road trip I may go more miles between changes.  I also like to monitor the oil condition.  I look for excessive blackness, moisture, and viscosity changes,

Spark Plugs (for gasoline engines)

Back in the day spark plugs only lasted about 10k miles.  Cars built since about 1995 can go up to 100k miles on a set of spark plugs, although they are much more expensive spark plugs made with precious metals like platinum or iridium.  The spark plug type and engine dynamics vary the recommended change interval so check with the maintenance schedule for your particular car to find the recommended change interval.  My cars all require spark plugs every 60k miles.  I prefer to use the cars original spark plug.  Often you can get the supplier branded plug which is equivalent.  For instance, many Mercedes use Bosch spark plugs so you can buy the Bosch branded plugs versus buying them directly from Mercedes.  If you let the plugs go too long, the firing voltage increases to where the energy will find new creative paths to ground.  This means failed secondary ignition components which for most modern cars is now the coils.  Best to maintain your spark plugs to prevent that.  

Transmission Oil

Modern cars with automatic transmissions are starting to go to longer term maintenance intervals, some claiming the life of the car.   My XJR had such a transmission.  However, at 120k miles it started doing some strange things.  It would lock up the converter and stall the engine when coming to a stop.  It happened randomly and not all that often but it was really annoying when it happened.  Sometimes it would take several attempts to get going again.  I drained the fluid to change the filter and found the fluid was very cloudy and brown.  It made a fine mud in the pan too.  Suspecting a failing converter clutch I replace the transmission torque converter, the fluid, and filter.  Just as I got the car going again it locked up.  This time I removed the valve body and disassembled it.  I found that mud all over in the valve body clogging passages and orifices and gumming everything up.  I cleaned everything thoroughly and the problem was solved.  So, I now wonder if that lifetime fluid thing really works.  

Brakes

Brakes are an area of particular concern and cheap parts should never be used here.  I had an F250 truck I once installed a set on $19 front brake pads in.  The thing was dangerous after that.  It just could not stop.  I think stopping distance must have increased by at least 30%.  It was awful.  I replaced them a few months later with a good set of Hawk premium pads (about $80) and told myself never again will I use cheap pads.  Another thing cheap pads do is dirty your wheels and squeal.  Not at all worth it.  I prefer Hawk but there are other good brands as well.

Fuel

Even the gas you use makes a difference.  Never try and be cheap by putting in a lower octane than the manufacturer requires.  Always go equal or higher on octane rating.  Also, don't use cheap gas, ever.  Get it from a Shell, Exxon, Mobil, BP, Chevron, etc.  I once got "premium" gas at a Hucks station and put it in my Crown Vic (which only required regular).  The car rattled bad with detonation.  Definitely NOT premium in any way.  Another time I put premium from a no-name station in my XJ8L (which requires premium).  I was on a trip and as I was driving down the highway I noticed a lack of power, surging, and very bad fuel economy (like 10mpg off).  I suspect they had made "premium" by dumping a whole bunch of alcohol in it.  While this does increase the octane rating to prevent detonation, it also has less energy and requires a different air fuel ratio.  I went ahead and continued driving until my tank was down and filled up at a Shell.  Problem solved.  Another problem you can have with cheap gas is poor maintenance of the tanks and pumps at the station which can leave dirt and other material in the fuel.  This plugs your fuel filter and can damage pumps.  The detergents in the fuel are required to keep your fuel system clean.  Back in the late 1980's we had to clean injectors on dozens of cars every week at the shop before fuels started getting the detergents they needed and injector designs improved.   Cheap gas may lack these important detergents.

These detergents not only clean the fuel system but they also help reduce carbon in the engine.  Engine carbon buildup can cause all sorts or problems.  Here is one example of a van with a bad knock that was just carbon.  We fixed this with a few bottles of water.

Don't try this unless you know what you are doing.  Be careful not to get too much water into the engine too fast.  Major engine damage can occur if done incorrectly.  With that said, I have done this to many engines before and never had a problem. You start by getting the carbon hot.  Hold the engine speed up around 3000rpm or so for several minutes.  This will make a terrible noise but there is no good way around it.  Now, find a small vacuum line that goes to a place in the intake manifold that will effect all cylinders.  A hose close to the throttle works.  While holding the engine speed above 3000 put the hose into a full water bottle and let the vacuum suck the water into the engine.  You will need to apply more throttle as the water will make the engine speed drop.  Often you will need to hit 3/4 throttle or so.  After all the water is in the engine you can let it idle again.  If the noise is still present, repeat.  The van above took 3 bottles (16oz to 20oz each) to clear up the knock.

Belts

Most modern cars use Poly-V bents that follow a long path and wrap around pulleys in different directions.  They are commonly referred to as serpentine belts because of this.  These belts are much better than the old V-belts back in the day.  They typically last 60k miles or more.  However, if you run them to failure bad things can happen.  They can get tangles up in adjacent components like hoses, wire harnesses, and other parts and rip them all apart.  Even if that does not happen you are generally stuck on the side of the road since you will often loose charging, cooling, power steering, etc.  Best to keep them in good shape.  Changing them is usually easy and most cars have a routing map under the hood in case you forget how they go on.  These belts can actually accept a certain level of cracking on the ribs and still be OK.  It is easiest to see the cracking where the belt wraps backwards over the pulley (the ribs on the outside).  If any chinks are missing replace the belt right away.  If the cracking gets too excessive change the belt.  

Cam drive belts (timing belts) are a special case.  These must be replaced at the factory specified interval.  It is best to get a complete kit when replacing them.  these kits often include all idlers, a water pump, and tensioners depending on the application.  When these belts fail, severe engine damage generally occurs.  Some engines are designed so that timing belt failure will not damage the engine.  these engines are often called free-wheeling but they are the exception not the rule.  Luckily most modern cars have gone back to chain drives but back in the 1980's and 1990's many cars had timing belts.  Changing timing belts can involve special tools and often involves at least a half day of labor or more.  

Hoses

Cooling system failures are one of the most common causes of cars ending up on the side of the road.  There are many cooling hoses on most modern cars.  If you keep your coolant in good condition these hoses can often last 15 years.  However, you need to check them periodically.  If they get harder or softer replace them right away.  After about 15 years you need to really get them replaced.  In some cases you may need to replace them earlier than that.  

Suspension

Some roads, like the terrible roads here in the Midwest, can really abuse your cars suspension causing premature wear and failure of wheel bearings and suspension components.  This can be dangerous!  Inspect your suspension at least yearly.  Rock the steering wheel back of forth and feel for any clunks or looseness. Raise the wheels off the ground with a floor jack and try to move the top and bottom of the wheel in and out firmly.  Modern cars with sealed wheel bearings should have no looseness.  Visually inspect all suspension bushings too.  

Service Information and Tools

Model year 1996 or newer vehicles sold in the US fall under a law called Service Information Rule (SIR) which dictates that OEM service information and electronic service tool must be made available outside the OEM dealer network for "a reasonable fee" which the government "helps" the OEM decide.  Because of this, you can access the factory manuals to service your vehicle.  It is required that it be a website where users can subscribe for various access levels.  The National Automotive Service Task Force (NASTF) polices this to make sure OEM are complying.  You can find their website here: http://nastf.org/ .  You can sign up for a free account.  They keep a directory of where to find these OEM service information websites since they are rarely linked from the OEM's main public website.  Right-to-Repair laws are expanding this beyond emissions related system to include the whole vehicle.    

More to come....

I plan to add more to this so check back occasionally.