[getmygoat]

Hi all,

Trying to confirm whether my rear main seal is leaking. Oil on starter bolts, dripping off bottom of bell housing, bottom of muncie has a drop, and a drop at center of rear oil pan rail. Also drops of oil on other parts of oil pan rail (like where those flat washers are positioned on the rear side of pan).

Likely the rear main but I'd like to confirm absolutely that's where its coming from. I've checked the above sources.. valley pan, distributor, valve covers, with no smoking gun. However, given the stakes involved (e.g. pulling the motor to fix the rear main), Id like conclusive proof. If I just run it on ramps for a few minutes, I don't get anything. Seems like I need to drive it to get it leaking. Maybe I need to just run it on the ramps for 15 minutes or something. Would like to avoid wind blowing it around, but I suspect the flywheel is flinging it everywhere.

Any suggestions?

[Cardo]

Read this thread. I had the same exact situation as far as driving vs stationary, and what really put me onto this was the fact that it leaked a lot more in city driving vs just straight highway driving. The sloshing from taking off from a light made it leak significantly more. http://forums.maxperformanceinc.com/...d.php?t=471237

[mgarblik]

My current favorite method for isolating an oil leak is using an EVAP smoke machine. You introduce a white harmless smoke into the valve cover and look for where it comes out. Presto, there is the leak path. You could possibly borrow the machine or rent one from a local shop or even a car dealership if you know someone. A commercial unit is pretty expensive to buy. I bought a used commercial unit. There are plans on E-bay to build your own. All kinds of semi-frightening ones available on the internet that are low cost. Pick your poison. Great for finding exhaust leaks, transmission leaks, power steering leaks and engine oil leaks. Also good for doing what were designed for, finding EVAP emissions leaks.

["QUICK-SILVER"]

Pretty much going to need the flywheel off to pin-point where the leak is.

A little air pressure, in the crankcase, and a strong mix of soapy water will show where the leak is.

Could rig up an inline smoke box to use while you're spraying soapy water.

Some parting line type leaks can be sealed up without taking an engine apart.
By pulling a vacuum in the block, spray the leak area with brake clean and let it dry, then putting a good sealer over the leak and letting vacuum suck it in.

Clay

[mgarblik]

Originally Posted by "QUICK-SILVER"

Pretty much going to need the flywheel off to pin-point where the leak is.

A little air pressure, in the crankcase, and a strong mix of soapy water will show where the leak is.

Could rig up an inline smoke box to use while you're spraying soapy water.

Some parting line type leaks can be sealed up without taking an engine apart.
By pulling a vacuum in the block, spray the leak area with brake clean and let it dry, then putting a good sealer over the leak and letting vacuum suck it in.

Clay

I successfully repaired a Mercedes oil pan leak with this method. Removing the oil pan for a "correct repair" would have meant engine and transmission removal as the oil pan was a structural member of the transmission. Nearly a 30 hour repair done in a couple hours using the vacuum method you describe. He sold the car a few months after that repair but the leak had stopped.