Upper Oil Leak Questions

TurboRuf · 11-09-2009, 06:29 PM

Last summer I noticed some oil buildup on the top of my 85 930 engine while putting in a new fan housing. Thinking this was coming from the thermostat, I cleaned up the oil and replaced the thermostat and o-ring.

Recently I went to replace my alternator and noticed there is still some serious oil buildup on the top of the engine. So my first question is... where do you think this is coming from?

I’m hoping it is just the oil breather gasket but I can’t see under the CIS to verify. If I’m lucky and that’s all it is, how difficult is it to replace? What needs to be pulled to get access to it?

Thanks!

Flat6pac · 11-09-2009, 06:55 PM

It is coming off the case breather or the breather hose or the idiot light switch.
looks like the case breather in the picture.
Bruce

TurboRuf · 11-09-2009, 07:32 PM

Thanks Bruce! How hard is it to remove the case breather? What major parts do you need to remove to get to it? I have the Air Box, fan, and intercooler already pulled.

proffighter · proffighter's Garage

Is there any oil around the breather? If, it's easy to reseal. But I am not sure, because the fan blows in this direction, don't think much oil would reach this area from breather... Just my thought

TurboRuf · 11-13-2009, 04:20 PM

I took some photos of the oil breather and the oil doesn't appear to be coming from it. The PO apparently liked to use generous amounts of RTV. I can't get a good angle to see the front side so I can't be 100% sure it's not leaking.

Could it be coming from the case halves?

ben parrish · 11-13-2009, 04:36 PM

It still looks like that cover is leaking. Additionally, that vent "hose" sure looks odd, It looks like it is metal and it goes inside the cover nipple. Pretty sure it should be a rubber hose and go over the barb. It could be a combination of all the gaskets up there.
I am going through the same thing right now. Had a combination of three small leaks as well as a loose hose. My entire intake has been removed and I just got the parts from pelican today to get it all fixed (fingers crossed)
good luck,
Ben

TurboRuf · 11-13-2009, 04:50 PM

Thanks Ben, I thought the hose looked odd as well. I think I'm just going to pull everything and do the job right just to make sure.

ben parrish · 11-13-2009, 05:07 PM

You will most likely find a few hoses that need replacing when you get back there. Not a real hard job, just a pain removing the intake. I decided to replace every thing back there that even looked suspect. I don't want to have to this again anytime soon.
Ben

jimbauman · 11-13-2009, 05:13 PM

Lowering the engine a few inches may also get you easier access...

JB

j_mancini · 11-13-2009, 05:21 PM

Two years ago when I refurbished my CIS, I replaced that breather cap gasket.

Yeah, there was an engine under all that gunk! This year when I swapped out my alternator, I found the same thing - oil/dirt buildup, just not 30 yrs worth. When I replaced that gasket, I installed it dry (cleaned up the parts well, of course). This time, I am thinking something like Curil-T will fix it (hopefully!). Out comes the engine tomorrow.

Ditto on the transmission shift plate cover....new gasket (installed dry) that subsequently leaked again! I replaced that one this year, with Curil-T, and so far it's not leaking.

Flat6pac · 11-13-2009, 05:22 PM

I find it easier to pull the engine on a turbo and set the valves. The seal between the case and the breather is the weepage because it has shrunk. I always install it with 574 on the gasket.
The hose looks weird because the engine is a turbo and that is the proper breather hose.
Change the thermostat and the idiot light switch when you get in the area of the breather.
Bruce

ben parrish · 11-13-2009, 05:56 PM

Bruce, I just realized it was a turbo....slightly differnt than the standard s/u. Why is that tube metal?
The breather hose that goes to the intake may be loose also.

Walt Fricke · 11-13-2009, 07:20 PM

John M

If your reseal of the transmission shift fork plate doesn't hold, there is another thing you can check:

Is the plate warped.

I generally just use orange Loctite instead of a gasket here, works fine. But it didn't, so I added a gasket. Better, but didn't resolve the issue. Next time I took the fork off and put a straight edge to the machined face of the plate. Aha.

Not too likely to be your problem (I think this is usually the result of a nasty malfunction in the gears, leading to an expensive rebuild, but the bend this causes in the plate gets missed).

But good to know and easy to check.

Walt

j_mancini · 11-14-2009, 06:40 PM

Thanks Walt, so far so good. I hadn't considered that it may be warped.

Actually I pulled the engine/trans today for other repairs. As for the oil leak, it appears to be the breather hose and maybe the thermostat.

Funny thing is - the hose is new, as is the thermostat o-ring! I changed them when I refurb'd the CIS. Clamp on the breather hose is tight, so what gives??? I did have to tweak the hose a bit when installing, but seems unlikely that would cause it to leak. Any thoughts? Is there some trick to getting this hose to seal?

Walt Fricke · 11-14-2009, 09:20 PM

Rear main seal? Does the "gap" at the bottom of the engine/tranny mating surface show leakage?

TurboRuf · 11-23-2009, 12:49 PM

Is there any way to replace the oil breather gasket without pulling the CIS/intake? Can you pull the CIS/intake without dropping the engine? From what I can see there is a CIS mount in the way of removing the breather with the CIS/intake still in place.

Walt Fricke · 11-23-2009, 12:59 PM

I think you can pull the breather cover without removing the CIS. Two things will give you some form of pretzel access: pulling the rubber boot connecting the two sides of the CIS, and doing a "partial drop" of the engine. There is a Pelican FAQ on this, but it involves disconnecting the shift coupler, and then removing the rear motor mount big bolts with a jack under the rear of the engine, and lowering the engine until hoses and wires start to get tight. Then block the unit so it can't sink lower if the jack slowly retreats.

I don't think anything else attaches to the four 6mm studs which hold the breather on. I think you may have enough clearance to the bottom of the CIS airbox.

No matter what I do I always get some grime in this area. Luckily not as nasty as some of the photos.

Walt