stangrev

After a fuel service last month, and valve cleaning today (assumed misfire codes were carbon related), my son (Audi tech) discovered antifreeze leaking down cylinder wall. He, and techs in shop, have never seen this....

My 08 S Line was bought via EBay auction from PA dealer 3/2014, has 84K.
My coolant warning light went on a week ago...the reservoir was nearly empty when the light went on.

Is this that rare? It's a pain to remove the heads...and I'm wondering if its just the tip pf the iceberg. Hoping I didn't end up with the Old Maid card....

raj99

I've got a few questions, but first will attempt to answer yours:

Leaking headgaskets are prone on any vehicle and is not something I would consider rare, but certainly aren't the norm.

Removing the heads is a PITA, since there's a lot of work that's required in advance...there's a great write-up on the forum, just search.

As for diagnosing the actual issues, when you checked the oil, are you seeing coolant in there? Any white smoke out of the tailpipes?

Also, before you go in for a full teardown, give one of those 'magic' sealers a try (i.e. Bar's Leaks). Good luck and hopefully it's fixable

stangrev

Antifreeze was seen in the cylinder during a compression check....and, Yes on the white smoke on start-up, plus the cylinder inspected was one of the misfire code locations.
I'm afraid of a cracked block...loss of coolant was too quick. I will check the oil...the engine runs great when warm, has good compression and gets 30mpg highway.

stangrev

More info...
Antifreeze, maybe a teaspoon in volume, seen in #1 cylinder, via a 90 degree borescope down the plug opening...there was a yellow stain down the cylinder wall suggesting a long-standing problem...there is also a small leak from the thermostat housing we initially thought was the problem until the valves were cleaned (pretty significant carbon buildup) and cylinder inspected.
Unknowns at this time: 1. Condition of heads
2. Source of leak
3. Condition of block
We're thinking the heads can't be shaved if warped because of the high tolerance (12.5:1). Will be assessing (Vag Com) this week after a few cold starts...I did code an oxygen sensor, most likely a victim of the coolant contamination found at valve cleaning.