Head gasket failure or something worse?? - Page 2

missfire · 02-05-13, 08:10 AM

Quote:

Originally Posted by missfire

It'll lose oil pressure through the gasket though, won't it?

Quote:

Originally Posted by andydunn2

Not sure...

.

Quote:

Originally Posted by fj1200

Going back to my days at the dealer now. We did MANY head gaskets on 12V v6 engines, was always oil leakage.

missfire · 02-05-13, 08:14 AM

Is it overheating or anything? Might just be phouked...

compression test, hot and cold.

TeXerv · 02-05-13, 08:23 AM

Quote:

Originally Posted by missfire

Is it overheating or anything? Might just be phouked...

compression test, hot and cold.

If I heard him right, the only symptoms are Mayonnaise and low oil pressure. No overheating, no trace of oil in water / water in oil.
And mostly Mayonnaise on the filler cap (only) is evidence for cold engine operations with resulting condensates - not more.

missfire · 02-05-13, 08:32 AM

Yes I know.

I've had that in a few of mine, mayo, and in the breather pipes too. A good oil change and longer drives as you say.

TeXerv · 02-05-13, 09:44 AM

Quote:

Originally Posted by missfire

...mayo, and in the breather pipes too.

A very good hint! The crankcase breather should be cleaned as well and after renewing the engine oil proceed a longer trip on a motorway.

andydunn2 · 02-05-13, 09:56 PM

Going to drop the oil and filter at the weekend and clean out the breathers and see what happens, providing I can get better oil pressure than the 0.5 Bar at idle Im getting now I will give it a decent run.

To answer the other question, no it doesn't overheat it's just dropping oil pressure (5 bar when cold dropping to 0.5 bar when hot) and mayonnaise in and around the filler cap and using some water.

Cheers for your help guys...

andydunn2 · 21-03-14, 09:37 PM

Quote:

Originally Posted by fj1200

Going back to my days at the dealer now. We did MANY head gaskets on 12V v6 engines, was always oil leakage. Usually they leaked when piping hot at RPM. The place to look is in the valley between cylinders 4 and 5 (front two of your passenger side). Get it good and hot, clean aggressively and hold engine at 3K revs. Watch for oil forming at head to gasket joint.

The other common failure is the oil cooler, check the overflow bottle for oil residue. Due to differential pressures the two fluids go either way (kinky, no?). When the engine is running the oil pressure is higher so oil migrates to the coolant. After shutdown the cooling system pressure is higher so coolant migrates into the oil.

Hope this helps, Cheers.

Dan

Guess what now the weather has decided to warm up a little I decided to throw a new oil cooler on today prior to pulling the engine out (I have a spare engine to put in) and it's solved the problem

Got plenty of other issues to sort out but at least at the moment this is one less headache...

02-05-13, 09:56 PM	#16
andydunn2 Ragtop Collector Classic Audi Club Member Join Date: Nov 2010 Location: Chorley Posts: 1,463	Going to drop the oil and filter at the weekend and clean out the breathers and see what happens, providing I can get better oil pressure than the 0.5 Bar at idle Im getting now I will give it a decent run. To answer the other question, no it doesn't overheat it's just dropping oil pressure (5 bar when cold dropping to 0.5 bar when hot) and mayonnaise in and around the filler cap and using some water. Cheers for your help guys... __________________ "Earl" 1998 2.8 V6 Cabriolet "The Duke" 1997 2.6 V6 Cabriolet (Sold....sadly) Project "Best of Both Worlds" 1995 S2 Quattro Cabriolet

02-05-13, 08:14 AM	#12
missfire making wooden things Classic Audi Club Member Join Date: Dec 2009 Location: cow land Posts: 8,156	Is it overheating or anything? Might just be phouked... compression test, hot and cold.

02-05-13, 08:32 AM	#14
missfire making wooden things Classic Audi Club Member Join Date: Dec 2009 Location: cow land Posts: 8,156	Yes I know. I've had that in a few of mine, mayo, and in the breather pipes too. A good oil change and longer drives as you say.