astone (Andy)

It is now the opinion that there was a "pinhole leak in one of the cylinder heads" in the service manager's words. Apparently some JB Weld has been used to repair it and I can pick the car up today. I'm not sure how a cylinder head leak would drip outside the block or how a cylinder head has a pinhole leak, but I'm not a mechanic. Maybe he meant there was a leak in valve cover? Will post my findings after driving the car again, but I'd love to hear some feedback on the current diagnosis and repair method.

I searched (using basic keywords) and couldn't find anything similar ever being reported.

Related thread if you desire background info.<ul><li><a href="https://forums.audiworld.com/rockymtn/msgs/92127.phtml">https://forums.audiworld.com/rockymtn/msgs/92127.phtml</a</li></ul>

DocWyte

If the head has a pin hole leak, I'd demand a new head!

furtherrad

2nd. JB Weld doesn't fix the problem. It's a temporary fix.

gietl

If it is a valve cover leaking, RTV silicone, high temp is a decent solution. Still, if it is a bad gasket, replace the freaking gasket and add RTV to fill any potential gaps.

Regardless, you are in for more "leaks" at some point if they are just patching things.

I would recommend finding out EXACTLY where they say the leak is coming from. It doesn't matter if you are a mechanic or mechanically inclined, the exact terms are what's important here.

Your resources on AW can help you out with what they were trying to really do.

astone (Andy)

There was no sign of accident to cause it, no sign of impact from tool or rock either. Their opinion is that it is a manufacturer defect in the metal itself. My understanding is that the cylinder head cover is a poured piece and somehow when the motor is shut down, oil drips from a pinhole sized hole in the metal. Mechanic said that he had never seen it before. I guess I will give it a week to make sure that that is in fact the problem, but I am predicting another call to the extended warranty company to cover the head replacement. With my luck I should have known that I'd get the problem that no one has ever seen before and is physically right in line with the valve gasket, turbo line, and tensioner seals.

gietl

Well good luck regardless, definitely push to get that work done if possible. I'd hate to see you have some huge failure due to a manufacturer defect.

urq20vt

Seriously though, a friend of mine has been driving a motorcycle that had a hole in the crank case patched with JB Weld for years and thousands of miles with no issues.

I probably wouldn't want it done to my car, but if a little local porosity is all it is, I wouldn't worry too much. Makes me wonder if there might be other problem areas with the head.

Reggie

extremes and be subject to oils and vibration along with the high temps and pressures.

Trango

If it's actually a valve cover:
The good news is, though, that if it fails off warranty, valve cover repairs are easy to effect, by taking the part off and repairing it.

If it is truly a cylinder head itself - mechanical epoxy is not an appropriate repair. I mean, a true "pinhole" leak isn't terrible, but in a cast or a machined part with any sort of thickness, there is no such thing as a true "pinhole" leak unless put there by a laser - seriously.

I would ask for a full report by the service writer AND the technician, if available. A leak in a thin-gauge, removeable part like a valve cover is a whole different animal than a cyl head.

astone (Andy)

not the piston or anything internal, and not the valve cover.

How difficult is a true repair, if there is such a thing, to a hole in the cylinder head? Or better yet, replacement.