kanefire222

My car has been leaking oil since i've had it for a year and a half. I always make sure its topped off and its at the right oil level. But could leaking oil affect the the way the car runs at all? Is leaking oil a a major deal? It leaks a lot in the front of the engine right above the oil pan as well as in the back of the engine. The estimate to fix this problem was around $2800. The mechanic said he had to machine repair each cylinder head.

ivans A8

major oil leak sources on A8 is: oil pan, valve cover gasket, cam position sensors, breather hoses, oil cooler and sometimes head gasket. In 1.5 years of ownership I one by one replaced oil pan gasket, valve cover gasket, cam position cover gasket and valve cover gaskets. Breather hoses is next on my list and my heads dont leak any oil so and oil cooler. All at about $300 max + labour. I dont see why would someone want to machine cylinder heads, I dont think there is a single member on this forum who done that.

JimR

Pre-facelift car? On the passenger side?

This is often a leak through the oil pressure sending unit, which mounts on the side of oil cooler. It's a pretty cheap part (I think it was $10 or so), and is relatively easily accessible, once the air box is removed.

Check that.

97RoninA8

... I think that's why my alternator is soiled in oil, and that general area starts to stink like a burned candle after about 5 minutes of driving, then goes away... best guess is, there's a seep until pressure is built up and then everything seals up nicely.

Do you have a part number for this part, and maybe a photo of where it mounts, etc? Where can I get it?

barryl

Hello,

I had a very bad oil leak that turned out to be
a bad headgasket. I guess that what is meant by
'machine cylinder heads'. BTW, I have also done
the valve cover gaskets (twice), breather hoses,
and a few other things.

I bought my car with 70K miles on it. I now have
125K and need to change the valve cover gaskets
one more time.

The oil leak won't damage the engine as long as
you make sure there is sufficient oil. Oil leaking
is bad for the driveway, and any rubber bits
that the oil runs down on it's way to the
ground. Check your suspension bits like
sway bar drop links and things to make sure
the rubber is not rotting them.

Barry

ivans A8

I know some members done that and it could me a problem. I just dont see a reason for machining heads. Is engine been overheated?

MateoA8

and live with it. I've had my 98 A8 for 3 years now and it leaks/burns oil, not sure which one since I can't find evidence of an oil leak (no oil on my garage floor). I usually have to add a half quart between changes. Hey, it's way better than my MZB 300E I had that burned a quart every 1000 miles and made it to so I had to change the spark plugs at every oil change, but it was cheaper than the 3K it would have cost to fix the problem (so said my mec). So....

A8CT

and you'll be looking at it. 15-20 mins and you're done. It threads in like an o2 sensor and has a single wire hookup.

Just ask your dealer for the "oil pressure switch" for your year. If you get change for a $20, you got the right one

Bob

JimR

Exactly, on all that.

dieselgeek.com

Both of my '97's head gaskets leaked on the outside front (passenger head) and rear corner (driver's head) due to bad design. The embedded rubber on the HG around the oil return holes had disintegrated and so the oil seeped to the outside. This caked up on the alternator and the rear corner of the driver's side head. You can see the oil run out of the front corner of the passenger head after you clean it off well with brakecleaner spray. The oil comes from the gap between the cylinder head and engine block and nowhere else.

I couldn't stand the smell, the oil drips/puddles and the bad karma of dropping oil everywhere so I sucked it up and pulled the heads and had my machinist "go through" them for a grand or so. He put in new guides and lapped in the valves. He also cleaned them and installed new chains for the cams. I put the engine back together and no more leaks or guilt. I replaced everything I could while I was in there like injector seals, coolant hoses, o-rings, knock sensors, etc. I don't want to get back in there for a while. Blah.

The heads were really nice though. From the factory, the heads' combustion chambers were cnc-milled for perfect shape. Wish I had taken pictures...