Help, source of leak...

[Fisherman]

On my 81 SD there is an oil leak at the rear of the engine on the passenger side. This leak is only evident after a hard hill climb and is definitely motor oil but for the life of me I cannot figure out where it is coming from.

I just replaced all the o-rings on the turbo drain and the air filter/cyclone drain. This leak dumps oil onto the heat shield over the exhaust manifold just behind the air cleaner.

Has anyone chased this leak down before?
If I hadn't done the seals on all this stuff I would have guessed it to be the piping from the aircleaner but it is closer to the engine than where this pipe comes out fo the aircleaner. Could it be from the manifold? Makes no sense to me how oil would be getting into the manifold (no egr). Maybe head gasket but it only does it on hard hill climbs so this doesn't really make sense.

This is the last leak (I hope) and then I am finally done with this car.

Thanks in advance for your input.

[vwbuge]

Could the oil be coming from a bit lower. Wind pushing it up maybe?

[Fisherman]

My guess would coming from teh front of the motor maybe. The bottom of the heat shield is pretty clean and it would probably be caked if it were coming from below.
I need to find this leak but just don't want to pull the turbo etc without having some ideas first.

My other thought is that the cyclone is dumping oily residue into the intake manifold during heavy load and this is leaking out of the bottom of the intake manifold. Could be that it has been doing this for years so no tightening of the manifold bolts is going to help at this point.

I think I'll keep digging around.

[Fisherman]

I think I found it. The back mount is broken off the bracket and was loose. I pulled it off so it wouldn't rattle around and that left the back mount hole on the air filter can open.
It appears that the oil that is taken in through the cyclone does not all get sucked into the manifold but some (at high boost especially) gets blown around inside the air filter can. This oil was then making it's way tot the open mount hole and dripping down onto the shield.

At least that's my hope. Haven;t had time to rioad tewst it as I need to change out the tranny filter and fluids first.

[Fisherman]

It appears to be coming from under the intake manifold down the passenger side of the motor and appears to be broader than orignally thought.

I'm open to ideas from anyone.

[sdparizona]

hello fisherman,
was looking for an update on this leak. I think I have the same leak and haven't been able to pinpoint it. any info you have learned since your post would be great. I am guessing you fixed it as your post had ended.
thanks
Scott
'85 300td 268,000

[leathermang]

Am I missing something ... are people avoiding saying the obvious ?
You need to clean your engine... then run it up the nearest hill...and then look at it to find the leak...

[Brian Carlton]

Originally Posted by Fisherman

It appears to be coming from under the intake manifold down the passenger side of the motor and appears to be broader than orignally thought.

I'm open to ideas from anyone.

What about just an old intake manifold gasket. On older engines, there is a decent amount of oil in the intake air. Maybe some of it is leaking past the gasket.

When I removed the manifolds from the 617, the entire right side of the engine has an oily residue all over it.

[sdparizona]

thanks for the vote of confidence leathermang,
I spent all weekend scrubbing with a toothbrush and have methodically been working on all my oil leaks. I have one that starts producing oil after just a couple of minutes it the rear right corner, but it is just a tiny bit of oil. can't quite tell if it is the head gasket or the gasket for the turbo oil feed line. after several rounds of thorough cleaning and running the engine for a couple of minutes it starts to drip down onto the tranny housing in the rear. used flashlights and mirrors and it is so tight back there it is hard to tell exactly where it is coming from. searching the threads has lead me to this problem posted by numerous folks and it seems most threads that are specific enough to trouble shoot lead to either a head gasket or oil feed line, yet these threads don't reach a conclusion--no follow up post. so I assume they have resolved the oil leak problem and moved on. Instead of starting a new thread with all the background info I was asking for a follow up. hoping to benefit from previously stated material without the need to arouse everyones suggestions, time better spent problem solving and brain storming other ideas. its a lot more fun for all of us here to sit around and think about upgrading the a/c with extras than to hear about yet another oil leak. my intention was to troubleshoot my problem and also get a post for a conclusion to this oil leak problem for others to find in the future instead of just getting a response privately, no need to constantly jam up the MS traffic with new threads or useless posts like this one.....

[Pete Burton]

I think that's usually due to the crankcase venting into the air cleaner, the air cleaner itself, and the cyclonic oil drain from the air cleaner back to the sump. If that air filter ran with a broken bracket for some time, it's probably worn away the boss from the oil cyclone that holds the o-ring that is SUPPOSED to make a good seal with the oil return tube. And/or that o-ring is very worn, hard or missing.

[Fisherman]

It is clearly the manifold gasket that is leaking. The oil that is being pushed through the air cleaner (CA Version) is blowing by the gasket and literally splattering around the top of the engine also. The main evidence however is a leak down the side of the motor on the passenger side under the manifolds. I have a new gasket just haven't had time to replace it yet. After tightening the manifold bolts it helped a little but obviously there is a buildup there now that will never seal unless you pull the manifolds and clean the surfaces.

I'm thinking of throwing a federal manifold and turbo on this thing to get rid of the spool up, spool down problem on the california version. The thing is a slug compared to my other cars.

[leathermang]

"thanks for the vote of confidence leathermang,"

I can't tell for sure how you took that... but really, I can't find NEW oil in an already oiled and dirty situation... the only way I know to find a leak is to have it clean... then let it leak...