93 Chevy G30 6.2L Lingering Oil Leak???

[Rif]

Hi All,

I have a 6.2L Chevy G30 mini school bus. It has 125k miles. I bought it in Nov. and in Dec I noticed a little drop of oil on the bottom of the oil pan cover just waiting to drop to the ground. I took it it and the mechanic found small leaks in one of the valve cover gaskets and the oil pan gasket. He replaced those two as well as the rear main for good measure and in so doing also used some type of sealant as well. Needless to say a day or two after I notice yet another little drop in the same place. I took it back and they said one of the bolts was able to be tightend up just a bit more. Didn't do the trick. A couple weeks past and I took it back in. He resealed the oil pan and rear main gaskets. Still same leak. the guy he called in the machine shop said the bearings or crank shaft could be slightly loose and thus pushing oil out. What can I do, I can't afford to have the tranny pulled at the point to check the crank shaft and bearings...???

Thanks,

Rif

[john8662]

I do doubt it's the rear main bearing.

What kind of RTV is the mechanic using? I'm certainly now under the impression that the store bought stuff is a little too tempermental and needs a 100% perfect sealing surface without oil and very ample amount of time to dry, otherwise it'll leak.

I've tried a silicone called The Right Stuff made by Permatex, it's about $15 a can, but well worth it.

Besides the valvecovers and rear main seal and pan leaking, I guess the other place to look would be the cam plug on the block, I've suspected these to be leaking, not something you want serviced in chassis tho (sets the endplay on the cam too).

Have the mechanic verify that the vacuum pump isn't leaking oil, yes, the vacuum pump. They fail and start leaking oil out the diaphram. Also check the connection between the block and the pump.

What does the valley of the engine look like? Wet? Maybe the leak is diesel?

J

[Rif]

John,

The mechanic used a spray on Permatex??? I'd say he probably did it in the late a.m. on wednesday and drove it back to work the next day around 11am. I believe he let it run on wednesday after putting it back together to see if it leaked. Is it possible it did not have enough time to dry?
About the spots you recommended to check, it sounds like a good idea but 1. that would cost me and 2. he seemed darn confident that the only leak was this "tiny" one from the back of the oil pan. Do you think I should have the oil pan replaced due to the "slight" imperfection? That'll cost me $500! What do you think of these additives that supposedly seal small leaks?

Thanks,

Rif