greenaudi100

Cylinder 1: 140
Cylinder 2: 150
Cylinder 3: 145
Cylinder 4: 130
Cylinder 5: 160

Cylinder 5 had some oil sitting around/under the plug...a lot of oil. I'm thinking the valve cover gasket needs replacing? Anyway, what do you think of those numbers? I know ideally they should be with 10% of each other. I'm pretty close to that. I think cylinder 5 read a little high because the oil sealed it up a little better. Thanks for any thoughts/input!

greenaudi100

I should mention this is on a cold motor. I know ideally they are supposed to be warmed up, but I have another project blocking me in the enclosed garage attached to the house (can't let it run).

UrS4boy

Well, you are at the bottom end of the scale. The fact that No.5 had oil leaking into it and the compression was higher tells me that you should not think about adding too much horsepower to your engine. It's a wee bit tired.

Reference post on compression ratios found with "Search"

https://www.audiworld.com/forums/sho...php?p=18931680

greenaudi100

What does the oil in there mean? Is that the valve cover gasket? Also, my understanding is that if the motor had been warmed up properly, those numbers would be higher (how much I don't know). Is that reasoning correct or can I pretty much assume I'm looking at the right numbers?

UrScubed

If it's not warmed up, then the test isn't accurate. I'm also very suspicious of the #5 compression number- #5 on Audis tends to run hot (especially with a stock exhaust manifold) and it's very unusual to see #5 higher than the other readings- it's typically the lowest.

I'd move the other car or just run a fan to blow out the exhaust for long enough for it to warm up, then retest.

UrS4boy

My guess is you have 1) a leaky cam cover gasket that is allowing oil into the No.5 sparkplug well and 2) your no. 5 sparkplug *might* be leaking, allowing oil into the cylinder wall (or, if not, you have a valve guide/seal problem on No. 5). The cam cover gasket is Item 17 (PN 034198025F) here, including the little joined circles that keep the oil out of the spark plug well:



To replace the cam cover gasket, you first need to remove the 20vTurbo Coil cover plate by removing the Item 34/35 bolts. Then you need to remove the Item 15 and 16 bolts (keep their positions clear somehow because they are different lengths and we don't want issues upon reinstalling). Then you might think the cam cover should come off but, in fact, it is still stuck fast to the head because you still need to remove the Item 19 bolts. Then the cam cover should come off (you might need to gently persuade it with a sharp wedge between the head and the cover and/or a quick rap with a Big F'n RUBBER hammer (careful with that.

Remove the cam cover, remove all traces of the old rubber gasket, including the half moons for the cam ends, wipe up and then install the new gasket. Most people use some type of RTV Silicon seal to help seal the half moons to the head and the cam cover.

HTH

greenaudi100

Thanks Dave, I will do this when I go in and do the timing belt in a week or so. I'll be sure to post up some pictures.