The Stovebolt Site Forums The Shop Area Engine Shop Replacing oil pan gasket

My oil pan seems to have a slow leak (original from purchase.)
So silly question: Do I have to pull the engine to get the pan off to replace the gasket? Or can I get it on a lift pull it form underneath?

Are we talking strait six? Small block? I assume you're referring to one of the trucks in your sig line.

I have a 1950 with a 235 and I can pull the pan easily. That's the limit of my experience in the ad truck.

You also probably want to poke around some more with a flash light. A pan leak, rear main leak, and front seal leak can all look the same based on the puddle on the ground.

Drive to the car wash and clean all the oil off the engine. Then drive home and check for oil leaks. If it's like my '54 was, it's leaking from every gasket and the rear main seal. If that's the case it's easier to pull the engine.

If you have the pan off might as well check a bearing or two. That's what I did now i'm $2000 and ankle deep into an engine rebuild!

yeah it's a 216. I have rubbed the seams dry with a shop rag and a week later it has an oil build up with hardly a mile driven since.

Yes Dave you can pull the pan without moving the engine. You may have to jack it up so the axle is hanging down for it to clear depending on what model it is.
Make sure the pan rail is straight before installing the new gaskets, Glue them to the clean block with Permatex Hi-Tack sealer and use some cut off bolts as studs to guide keep the gaskets aligned and guide the pan on straight. And don't over tighten the screws. Pay special attention to the end corks. Make sure they fit all the way into the groove and use a little RTV to seal the ends to the block, A LITTLE DAB WILL DO YA!!!! You can pre-form them by strapping them around a can or jar with a rubber band and put them in the microwave for a few minutes then let them cool.
That will take care of the pan leak but as Charlie alluded to, the other two places that are most likely the reason for your leak are the rear main seal and the front timing cover seal. Both of them are a butch to replace while the engine is in the vehicle, not impossible but difficult and more often than not a wasted effort.

And keep this in mind, these engines even leaked when they were new. I worked in Chevrolet Dealerships in the late 50's and early 60's and drip pans in the show rooms were a common sight.

Denny Graham
Sandwich, IL

I got the pan off my 216 in my '51 3100 without jacking it up or anything.

So, with more time and watching, I've determined it's the rear main seal.
This seems to be the only thing wrong after putting more than 20 miles on it and the engine is already tuned. If I were to pull the engine for this ($$$)....

1) Is there any thing else I should be seriously checking since the engine and my wallet will be out?

2) And just how deep in my pockets should I expect to dig?

I replaced just the lower half of the rear main seal in my 216, sure slowed down the oil to a trickle. In fact, its only a couple of drips where ever I park. Oil is cheap, and at home, I just have a cookie sheet sitting where I park to match the drips. Also, you can get larger drip pans, like 3'x5', if you aren't an exact parker, or if your four speed drips out the back a little, like mine! That's where cookie sheet number two lives.

You can replace the whole seal, by letting all the mains go, and pulling the crank down a bit, but I was too chicken. I thought I might end up with the new seal half way in, and no farther. I have to drive the truck everyday during the week for work, and didn't want that to happen.

Why not just drive it for a while, and have some fun? If you are worried about a couple of drips enraging others, just wire a 9x9 cake pan under there to catch the drips.