Saturday, March 15, 2008

Alternator Pulley Failure & wvo = fix it yourself

(136,673 miles)
About 10 days or so ago my car started squeaking at idle. For a day or so it was minor but then got louder. My initial thought was that it might be the water pump since I bought the car used and didn't know too much about the history of the car. The original owner told be that the belt was changed at 80k as required and the more I thought about it he had no reason to mislead me.

Living in California with a TDI means taking the car to a Diesel Guru as most mechanics & stealerships aren't familiar with them - especially with regards to a timing belt (the water pump is connected via the timing belt and one usually does both at the same time since it's so labor intensive). Once I took time to listen to the squeak I first thought it might be the steering pump. In the end the altenator pulley came off which isn't unusual.

Since we were dealing with serpentine belt area, it was a straight forward repair that any mechanic could do. The concern that comes to mind is having a mechanic work on the car after it's been moded to run on WVO. Like most small cars the engine bay on the TDI is cramped, especially with a WVO kit installed. So chances are that something will need to be moved out of the way for a repair. I'm figuring space is less of a concern with the bigger pick ups & Benz vehicles because in the videos/pix I've seen of these conversions there is plenty -o-room in the engine bay.

I decided to replace the alternator myself. I could have just replaced the pulley for $69 but a rebuilt 120amp alternator was $263. The OEM alternator on a 2002 Jetta TDI is 90AMPs. I figured with all the electricity I am pulling for the Vegtherm & line heaters it would be a good thing to upgrade. The only part of the veggie system I had to unhook were a few ground wires. I was able to move the purge valve out of the way without disconnecting it.

Below is a general info video


  1. I am wondering what exactly your symptoms were. I have a 2003 TDI Greasecar and now when I make a cold start the engine very lightly studders 2 or 3 times and my lights dim. I get a sqeak only shortly after start-up and it goes away. My vegtherm stopped working, or works less, at the same time this all started. If I push on the plastic shroud over the timing belt area I can make something kinnda knock or stick. The belts were replaced about 10,000 trouble free miles ago, at 92,000 miles. What do you think? Thanks for the video.

  2. I think we are dealing with different problems. My pulley evidently started to fail several month before it finally gave out. There was a slight jingle I would here at idle all the time, even when the engine was hot - such as at a traffic light when the sound would be reflected back to me off another car. I was in denial.

    Then the sound got louder and all the time . SO after searching the forums I realized it was most likely the steering pump or alt. pulley. The pulley actually failed pretty quickly once the sound got loud and you tell something eas wrong

    I never had a stutter at start or lights dimming. I also didn't push down on the cover you are talking about.

    Sounds like you might have electric issues if the light dim/vegtherm isn't working and a mechanical issue. The squeak noise could be the generator pulley or the idler gear as they tend to fail.

    sorry not to be of much help. I would definitely search the forums for squeak sound

  3. My alternator pulley fell off last Sunday morning and I am running around with no battery charge. The tdiclub has great pictures on hoe to replace the pulley with a $30 tool. I ordered the tool and am looking at pulleys. Found one for $64 and another for $94. The car is 400 milles short of 100,000.

  4. Wife's Jetta had same simptoms. Pulley fell off.. Thank god you posted this. TY