Cascade Crew

91RSVert · Posted: Sat Apr 23, 2011 11:29 am Post subject: Hidden oil leak

So I have a bad oil leak. Looked for it while I was doing suspension work. Cant seem to locate it. It is infact oil as I am loosing oil quickly.

Only the bellhousing is getting wet.

Oil pan, fully dry front and rear.
OPSU, fully dry
Up top around intake valley appears dry.
Front of flywheel is dry!! Shocked

Suggestions before I go yanking this trans out.

91RSVert · Posted: Sat Apr 23, 2011 11:54 am Post subject:

Does anyone here have a SBC laying out that they can post up some large pics of the rear of one with, and w/o a flywheel on it?

chevymad · Posted: Sat Apr 23, 2011 1:22 pm Post subject:

Only a few things back there that can leak. The cam plug and above it are 3 oil galley pipe plugs. Those are generally so stuck you cant remove them if you tried.. so probably not it. Then the rear main adapter if you're 1 piece, and the rear main seal. These leaks will generally run out of the inside of the bellhousing.

Up top there's the rear of the intake and the distributor gasket. Distributor gasket won't leak until high rpm.. even with half of it missing(found mine on the dyno) Then there's the usual culprit, one of the oil pressure sending units or their fittings. This is the only thing up there that is under pressure. These leaks usually run down over the top of the bellhousing, though some may get inside.

91RSVert · Posted: Sat Apr 23, 2011 3:05 pm Post subject:

I dont have any opsu's up top, mine is down on the side. However, I likely have a plug in that area.

If it was the rear main, it would get the front of the flywheel wet correct?

chevymad · Posted: Sat Apr 23, 2011 5:27 pm Post subject:

It may not. I've had some severe leakers that the flywheel looked dry to me.

aaron_sK · Posted: Sat Apr 23, 2011 6:46 pm Post subject:

91RSVert · Posted: Sun Apr 24, 2011 9:51 am Post subject:

So my best bet is to just yank the trans n look. Then order whatever is needed? *sigh*

Twilightoptics · Posted: Sun Apr 24, 2011 12:00 pm Post subject:

Or check all the things on the top. And check your lower oil pressure sensor.

91RSVert · Posted: Sun Apr 24, 2011 1:07 pm Post subject:

I checked the opsu first thing as I just replaced it late last year and figured it wiggled loose again.

91RSVert · Posted: Wed May 18, 2011 9:24 am Post subject:

So I put the dye in my motor last night. We have rain all next week, so I plan to rip it apart then.

ASSUMING it is the rear main. Should I replace with rubber, tuflon, or this fluoroelastomer stuff?

Also, never done a rear main before. But it looks like I remove trans, flywheel. Then about 3 bolts for the housing, pry it off. Then install new seal on workbench. Bolt it all back together? I know, easier said then done.

Twilightoptics · Posted: Wed May 18, 2011 2:14 pm Post subject:

Think it's 8 bolts to pull the housing off.

91RSVert · Posted: Wed May 18, 2011 5:17 pm Post subject:

8? ok. But bolt qty aside, does that sound correct?

And which type of material will last the longest?

Twilightoptics · Posted: Wed May 18, 2011 5:20 pm Post subject:

Didn't even know there were options for type of seal.

Yeah, install the new seal evenly and carefully into the housing. You'll also need a gasket for the housing.

Maybe someone else will chime in, as it's been a long time..... don't you pry the seal out and install on the motor because the housing is part of the pan sealing surface?

RSFreak · Posted: Wed May 18, 2011 5:54 pm Post subject:

chevymad · Posted: Wed May 18, 2011 6:27 pm Post subject:

I've always just left the housing on the motor and pried the seal out. They usually give you a plastic tapered thing to get it on over the crank. If not you can make one with pop bottle plastic.

I've heard they have different materials, but have always just used stock replacement and never had a problem.

91RSVert · Posted: Thu May 19, 2011 4:17 am Post subject:

BluFbdy · Posted: Thu May 19, 2011 1:24 pm Post subject:

You can leave the housing on like chevymad said, ideally the housing will never leak until you pull it, those gaskets are tight in theres and get stiff, once you pull it you crack it lol I just replaced the gasket on my 350 since it was already out

Even if the seal looks fine still replace it when I replaced the one on my 305 the seal looked good but swapping it stopped my leak, just pull the trans then the flywheel, and pull the old seal out, you can use a pick tool since the old ones getting.tossed anyway, coat the new one with a thin film of oil then slide it on and put it all back, torque the flywheel and all that jazz

91RSVert · Posted: Sat May 21, 2011 5:57 pm Post subject:

Update

I feel stupid. After yanking all the trans parts out, the back of the motor is bone dry. I looked around for over an hour trying to find a leak, no luck. Had someone else look at it and noticed there was oil around my valve covers. I go back up and sure enough, one of them was loose. Some how it had trickled down and was getting between the block n bell housing, and following it down.

However, not all is lost....
My throw out bearing is toast
Whoever did the t5 swap did not install an input shaft bushing
Found my coolant leak (waterpump on its way out)
my flywheel has been VERY hot and needs resurfaced
miss-matching bolts used to hold clutch stuff to flywheel
found some exhaust leaks

RSFreak · Posted: Sat May 21, 2011 6:40 pm Post subject:

You are supposed to put the dye in and then run the motor for a few minutes to see where it is coming from. Wink

Alphius · Posted: Sun May 22, 2011 12:48 am Post subject:

Wait... no input shaft bushing at all? Crazy. Sounds like a hodge-podge, so it's probably a good thing you are getting it all taken care of. Very Happy