I have a 2006 Audi A4 and recently the check engine light came on.. I had it checked and they said it was possibly the fuel cap and if the light comes back on I need a new fuel cap... So I have ordered one just waiting for it to come in. However after my oil change I noticed in my garage there is small oil spots, so I take it back thinking they didn't get the plug tight. They couldn't find anything leaking or "wet" inter the motor. I have noticed that I can hear the turbo spooling more so now then before. Is this a sign the turbo is going out or could it all be related to the gas cap gasket not sealing well? They told me if the gas cap didn't fix the engine light then they were going to have to smoke test to isolate the problem.. Any knowledge or helpful hint would be greatly appreciated.. I'm going to change the air filter today just for good measure.

 

If your turbo sounds like a dentist drill then you have a bad turbo on your hands. I had a bad gas cap before and it didn't make turbo spool louder. Have them smoke test it so you can find out what exactly is wrong.

 

Can u rebuild the turbo? Or just replace? Typical cost?

 

You can have the turbo rebuilt. Average price for that could be $200-$300. Alot of people buy new turbos. Don't buy a eBay turbo unless you want to be changing them out often. New good turbos should cost you $700+. Cost of a new turbo bought and installed will cost you around 1.5G-2grand.