Yesterday when I went to start my car it had a bit of trouble but still started on the first try. Then in nearly every gear it sputtered as if it were misfiring. I took it to a shop to diagnose and they said that spark plug #4 was installed incorrectly and was cross threaded, causing carbon to build up in the plug well. Also, he said the tapered cylinder head seat has been damaged and needs re-machining for a good seal. He said it would be about $7k in repairs if I went that route, so I asked for the keys.

Has anyone dealt with this before? I read online about Time-serts but I don't know if that is a safe fix. He said it appears the plug has been like this for a while and I'm not sure the last time the plugs were replaced. I have had no engine issues until this point. Any help?

 

Was a compression test performed , if so what were the reading. How did they come to the conclusion that it is a bad seat without removing the head & disassembling.
As far as the spark plug there are repair kits that work without head removal.

 

No compression test. Said he could see the galling on the tapered seal. He also said the spark plug electrode was completely gone and couldn't see it in the cylinder either. I asked him about time serts and he didnt recommend them because of the dual tapered sealing surface and something about there not being enough material to machine out. I'm just relaying what he said. If its a bunch of garbage let me know.

 

I can't really tell without looking at it myself. It does sound like you should get a second opinion. Condemning a valve seat without a compression test is not a very accurate way of making a diagnoses.

 

I think he's talking about the spark plug seat not a valve seat

 

Well all that aside, if the only option to fix it is to shell out enough money to buy a B6, then leave. Buy a replacement head from a parts car, get a timing belt kit and a top-end gasket set, and swap the head. DIY and you're way under a grand invested.

 

I would try a heli-coil, timesert, etc. Replace the threads and do a compression test and see how it works. The replaced threads will probably be stronger than original.

I don't know how he can tell that there's that much damage without removing the heads, and I can't imagine you could put in a spark plug so wrong to damage much more than the threads involved.

As was said before, if that doesn't work, you can always get a new head, timing belt kits, gaskets, etc. and replace it.

If there's a machine shop nearby, you could pull the head and have them take a look at it also...

 

Agreed. You need to fix the threads and then do a compression test to see if the broken electrode caused any damage. I wouldnt shell out any money till this is done at another shop.

 

He said changing the head out with 150k miles on the car would cause compression issues since its a DOHC. He said with the time certs there isnt enough material on the wall to replace the thread. Does anyone have experience with time certs/thread replacement?

 

Compression has more to do with piston rings wear. The valve guides can wear lossing compression but that is far less likely. Replacing the head will not have compression issues. He is full of bs. Not sure on the time cert, but since he is so full of ****, I take my car elsewhere.