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Volkswagen Jetta Maintenance and Repair

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Comments

  • bpeeblesbpeebles Posts: 4,080
    No need for engine heater if temps do not get below 10F. In fact, the TDI will START just fine at -20F... but will barely warm up after an hour of driving. (I know... I have experinced it many times)

    The reason TDI engine takes so long to warm up is because it is fuel-efficent. If you think about the physics of an automobile... it is basically converting the energy in the fuel to move the vehicle.

    If an engine is more efficent at converting the energy in the fuel ... there is less wasted as heat. Dont forget, the reason there is a cooling system (radiator) is to dispense of the by-product of HEAT.

    A 100% efficent engine would produce NO HEAT AT ALL because all the energy in the fuel would be converted to moving the vehicle.

    That is why ELECTRIC vehicles make no sense... they still need a kerosene tank and heater to keep the occupants warm in the winter.
  • ... but, to help out with that, the new TDIs have a special pre-heat function. It turns out that a first batch of US-destined TDIs did not have this enabled. Talk to your dealer - you may have one of them. This function is enabled via a quick change in the computer settings - takes about 2 minutes.
  • mrjettemrjette Posts: 122
    Can you explain the "pre-heat" function. How does it work? Is there an electric heater in the system somewhere? (an idea that would make some sense, like a blowdryer coil).

    Also, bpeebles says that the car is not warm after an hour - not my experieince at all. The car will not warm up while at idle, but once driven (even in cold temps) it reaches standard operating temp within a 5 minute window of normal and the heat in the car is fine. I do suggest the "cold weather package" for anyone who has cold days. The heated seats (at ~$100) are a great option.
  • jeffyscottjeffyscott Posts: 3,855
    Given the different experiences of bpeebles and mrjette, perhaps bpeebles has a broken thermostat???
  • I have a 98 Jetta and I have called around to find out what the difference is between the codes and no one can tell me. Does anyone know anything about a vw trani
  • bpeeblesbpeebles Posts: 4,080
    No "broken thermostat"... If the interiour heat is on "high" and fan on "high".... it pulls so much heat out of the engine that the engine will NEVER acheive operating temp.

    If I turn the interiour fan down a click or 2... then the engine temp comes up as expected.... turning the fan back to "high" will pull the engine temp back down.

    Do not forget that I am talking about what happens when outside temp is BELOW -15F. I also have the radiator covered to keep the cold-air blast out of it.

    Since I live in Vermont where there are exactly 2 interstate highways.... most of my driving is country-roads where the engine does not have to work very hard.

    Also, my TDI is well-broken-in and I use the best-possible oil (lowered internal friction = less heat). During the summer, I regularly get 55MPG.

    Additionally, "mrjette" has the Pumpe-duse engine which is radically different than my TDI engine. (also less efficent than mine) It is possible that VW has changed the cooling system to help get more heat to the interiour.
  • bpeeblesbpeebles Posts: 4,080
    The "pre heat" on the new-style Jetta is exactly what you describe... there is an electric heater coil (hair dryer) in the airstream of the interiour air-ducting.
  • Thanks for the info. The dealer says they can reset the radio for about 30 bucks.
  • bpeeblesbpeebles Posts: 4,080
    Actually, they ARE throwing parts at the problem. (aka GUESSING) It sure sounds as if they are just "pulling the code" and guessing what might be causing the problem.

    This does not surprise me at all. Dealerships are TRAINED to "fix it fast".... not to "diagnose the actual problem". This translates into what we call "shotgunning" the problem. (just keep throwing parts at it and charge the customer for them.)

    Although your dealership may be the best way for you to *eventually* get it fixed.... personally, I find it appalling that they do not actually MONITOR some key circuits while driving to actually isolate the issue a bit more.

    It is not very difficult to use a laptop computer to graph the TPS (ThrottlePositionSensor), MAF (MassAirFlow) and some other key inputs while actually driving to help pinpoint an elusive problem like this one. The flakey device will clearly show up as a "spike" on the graph when the problem happens.

    Also, there are a myriad of "diagnostics" that can be run on all the systems you have mentioned to help isolate a flakey device or sensor. One "quickey" way to help isolate things is to just UNPLUG the device in question and try driving with it like that.

    For example, unplugging the MAF will cause the ECU to fall back into "limp mode"... but the car will still be drivable. A classic method of isolating a bad MAF is to unplug it and see if the engine runs BETTER without it connected. (instead of running with bad signals from the MAF)

    A laptop computer in the hands of a competent trhoubleshooter is a wonder to behold. The most elusive problems are isolated with efficency. (no "shotgunning" required.)

    More than once, I have isolated a problem with one of my daughters VWs and printed out the results so they can present to the dealership. ( One time resulted in a free "steeringwheel position sensor" replacement and another time a free MAF was installed by dealership.)
  • pruzinkpruzink Posts: 112
    The 04 PD TDI's are having many failures with the EGR cooler (I just had mine replaced at 26K miles at no cost covered under the warranty, you have to 48K to get it done, after that it will be $900 out of your pocket). When the EGR cooler leaks, there won't be any external leakage as its going to end up mixed in with your EGR gasses into the intake. I would suggest getting this fixed asap as mine became a pretty serious leak in a very short period of time.
    I would not recomend running straight #1 diesel as it is much thinner and doesn't have the same lubricity as #2. You might be getting close to needing an intake manifold cleaning, you might want to press the dealer to do that while you are still under warranty also. There is a rather simple procedure for cleaning your fuel injectors with "Lubro Molly Diesel Purge" that I do every time that I replace my fuel filter. There are several writeup on how to do this at tdiclub and you can buy the diesel purge at tdiparts.com. Basically, the supply to your tandem fuel pump (the camshaft drives a pump that is a combination vacuum pump and fuel pump, it supplies the Pump Deuse fuel injectors) gets a piece of flexible tubing inserted, the return from the fuel injectors to the filter gets the same and the plastic tubes go into the can of diesel purge. Then you run the car until you empty the can (takes about 40 minutes) Good luck.
  • 2001 Jetta needs help.

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    I recently purchassed a 2001 Jetta GLS 2.0, and I need some information. I'vve always worked on my own cars, and I'm tight on cash right now so I don't want to start replacing the wrong parts. Here's the deal: The check engine light is on, and sometimes, the car Idles rough as if it's only running on 3 cyl. I've heard that throttle bodies on jetta's either go bad or get out of adjustment, but I'm inclined to think this would not cause an intermittent problem. I know It's time for a tune up, so I'm going to at least replace the wires and plugs. What sensors should I consider replacing? The car has 116,000 miles on it, and so far, nothing has been replaced. I've heard that the mass air flow sensor is a common culprit of jetta problems, and that it's easy to replace. Is this true? Many of my tools were stolen recently, and I'm timid about getting into a big project. I just need to be able to get to everything with standard ratchet and sockets. What about the plugs? Are the easy enough to get to from above the hood? I just want to fix what needs to be fixed right now because the car also needs new tires and the driver's door has a broken hinge bolt. I'm concerned about the rough idle. Sometimes, on the freeway, the car surges, too. It will be running fine at high speed and all of a sudden it will have a bunch more power and start going faster. This is without giving more gas or shifting (it's a manual). Any info would be greatly appreciated. Thanks!
    MIke
  • bpeeblesbpeebles Posts: 4,080
    Without knowing what code is causing the CEL -- you are shooting in the dark. The descriptin of your problem 'sounds' like an issue with the ignition.... not throttlebody.

    I would suggest you find out WHAT CODE is causing the CEL. Most autoparts stores will "pull the codes" for free.

    You need to determine WHICH ENGINE you have... the 2001 model year had an engine-change in the middle of it. The engine code is found on a sticker on the top of the timingbelt cover. It is a 3-letter designation.

    "AEG" engine is the older one with a throttle-cable
    "AVH" engine is the newer one WITHOUT a throttle-cable. (drive by wire!)

    If you have the newer one WITHOUT a throttlecable, there is a process wheras you can "calibrate" the throttlebody to make sure it is 'in sync' with the pedal.

    Replacing the MAF is trivial if you know which end of a phillips screwdriver to hold ;-) The MAF is screwed to the airfilter housing and has a clamp holding a tube to the throttlebody. Oh ya -- there is one electrical connector to pull off too. I have swapped MAFs between 2 VWs in the rain within 5 minutes... it is that simple. (I swapped between my daughters VWs to see if a problem moved to the other car)

    The Sparkplugs on the 2.0 engine are VERY VERY difficult to replace without the proper tools because the intake-plenum runs OVER the engine effectively covering the middle 2 sparkplugs.
  • I am new to the forum. I have an 02 Jetta Wagon with 48,000 miles. Until recently, I have LOVED this car but it is now starting to mysteriously lose oil. Two times in a row I have found that I am running completely dry after only 4,000 miles of driving. It is at the dealer right now for the 1,000 mile consumption test, but I am concerned that the dealer is going to tell me nothing is wrong since I am so close to the end of my warranty. I saw one posting on this problem from October 2002, but there wasn't an explanation. If anyone has any insight on what this could be I would really appreciate it. I am hoping to remain a loyal and happy Jetta driver! :)
  • chrisnhchrisnh Posts: 22
    Did not post my solution. It was definately a bad sparkplub wire to #1. I bought some liquid electrical tape for $6. Put on 10 coats or more on a weekend. Got lucky and while that should not have worked it did.

    One of the causes was the Jetta is missing a hood seal on the front. There was a 1/2 inch or 10mm plus gap after the hood firmly latched. All the New Hampshire slush and water came flying into the top of the engine. About $3 of 1/2 inch foam tape used to seal house windows reduced the gap to nothing and seemed to solve the problem.

    Chris
  • chrisnhchrisnh Posts: 22
    1995 Jetta. My daughter and I swaped cars. I went to a big city (7,000 people) and locked the car. When I returned, the key did not work. One of those wet and yucko days, slush up to my ankles. Hit the lock with some deicer. Nothing. Called my daughter and she told me to try it again. "Think good thoughts daddy". Presto, as I am telling her I did it 20 times before, the windows came down but car unlocked. Got the windows up and no more problems. Not being dumb I never tried to lock the car again. Gave the car back to her.

    A couple of weeks later she tell me she has not been able to lock it since then. I can lock the car with lock switch on the console, so something is telling the vacume to the door locks to work. We bought the car used and never could lock the car from the passenger side.

    Ideas, rather not spend $200 for a fix.

    Thanks - Chris
  • chrisnhchrisnh Posts: 22
    I ditto bpeebles, as you can see from my posts on this subject.

    The old spray bottle set to first to fine then to stream, worked for me. I could hear the spark and could see it in the twilight. I like to run this test when the engine is warm. Just in case the engine dies, the heat will help dry things out. Make sure you have a can of WD40 handy to get rid of the water.

    Again bpeebles has the right idea, what is really causing the problem(s)? Our Jetta would die on the road in the rain/slush snow. Wait 15 minutes and you could limp to a phone or home.

    I had first replaced the spark plug wires and distributor, then the coil. The problem did not go away. I figure that the mechanic with the proper tools damaged the wire to #1. My point is that it was water on the electrical system which caused the problem.

    When my sister-in-law came over with her Jetta, I did a side by side compairson. Just happened to look up at the raised hood and noticed one had a seal and the other did not. That was the cause, which let water get to the wires.
  • I had the same problem with rainy day's. It turned out to be the coil.
  • jeffyscottjeffyscott Posts: 3,855
    Its an 11 year old car, I'd just leave it unlocked :) .
  • Hopefully someone reading this has experienced my situation and could give me some advice. Recently, my front brake pad sensor light came on. The brakes did need to be replaced, so I took the car to my mechanic and he replaced the front brake pads. Now the front brake pad sensor light on my dash does not turn off. I called the VW dealership and they said that the light will only go off if I used their brake pads. I called my mechanic and he said that he used OEM brakepads from the Napa auto part store (these have sensors built into them just like the dealership pads). So, my question is - should I be replacing the brake pads to get the light to turn off or could there be something else wrong? My mechanic does not know what is causing the light to stay on. He says that he has no documentation on the light. The new brakes work just fine, but the yellow sensor light is driving me crazy! Please help... Thanks.
  • By the way, I forgot to mention that my car is a 2000 VW Jetta TDI.
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