Here's one for all you "in the know":

I have a 993tt (stock engine) that has been making hydraulic valve lifter noise since this car became mine months ago. When it's cold, the lifters clack like an old VW bus (tothe point of near mis-fire) until the car is warm and then no noise. Recently, there has been a "mechanical" noise that does not go away when the car is warmed up although as usual, the lifter noise goes away. My mechanic told me that he is almost entirely sure that this noise (driver's side bank only) is the valve guides. I have no smoke at start up or after. The car pulls hard as always (no power loss at all) and burns no more oil than the few drops (almost nothing at all) that it has. No leaks, nothing else other than this noise. he told me that the lifters could have caused this and of course, now I'm concerned. To replace lifters (my plan all along now that it's Spring here) is not a big deal but valve guides requires removal and machining of heads and tons more $$$.

Any thoughts? I trust my mechanic (for the most part) but I can't help but be cautious/suspicious/etc.

Thanks in advance...

 

Crap, I forgot to mention; the car has 38,000 KM on it (roughly 25,000 miles) and leak down five months ago was perfect and consistent.

 

Hi Alon,

I am sorry to say that your mechanic is probably right. When my exhaust valve guides went, my car had less than 40,000km on it. I think the city driving we do in Toronto is hard on the cars, high ambient temps plus very little opening up results in carbon build up which further increases the wear.

I was shocked that guides would go as such low mileage so I talked to Kevin @ Ultimate, Andial and RUF to get their opinions. Both said they've seen them on even lower mileage cars and also on the normally aspirated cars so this was nothing unique or unusual.

In my car, I noticed no changes in power, oil consumption or anything. The only thing I noticed was a noise that didn't go away and progressively got louder. I don't like to let a small thing turn into a big thing, so I had the top-end rebuilt by Courtney @ Autowerks right away. When he opened the engine, he found one exhaust valve guide was out of spec and the rest were marginal. The intake valves and guides were great. While he was in there, he replaced all the lifters.

The total cost for the repair was $9,000+ but the car runs great now and no noises. In fact, the car is quieter than I ever remember it!

Hope this helps,
Farzaan

ps - I believe I sold the car to your friend.

 

I know your car. Yes, Stan is a good friend of mine and I helped put him onto your car. I would not have endorsed it so highly had it not been scrutinized so carefully by Courtney. Don't get me wrong, I trust Courtney (he's getting my car on Tuesday) but I suppose that my mind is in denial of how large of a job it could be. I suppose we'll find out for sure next week.

 

Update:
I am happy to report that this noise was not the valve guides. Yes, I do have replace the lower lifters but I knew that already. This other noise that was originally diagnosed as being worn valve guides turned out to be something that I found; on the driver's side turbo, if I use a pair of pliers to slightly and gently "pull back" the wastegate actuator, the noise goes away. What I need to determine now is if that part is something that I can service (not the diaphram but it seems to be slightly siezed at the shaft that runs into the body of the turbo). If not, this may be the perfect excuse to go with new turbos (although my current budget does not support that given how much I am spending this year on home renos).