239 oil pan bolt leak

S

Seabees

Senior Member
Howdy boys, after putting in my break-in oil and letting it set overnight, I came out to a puddle on the floor :mad:. Upon inspection, oil is leaking at the bolts that hold the plate in place on the bottom of the pan. So, I pulled it off, ruining the gasket of course. I pushed the ring the bolts are attached to up, felt around underneath it, and of course there is no gasket on the inside of the pan, underneath the ring. The parts schematic doesn't show one on the inside of the pan, but there is one between the plate and the pan. So here's my question. Have any of you added a gasket under the ring, on the inside of the pan? Seems to me it would solve, or at least slow down, the loss of oil at this point. An extra swap or two of gasket sealer on each bolt would probably help also. What do you boys think? I think I'd like to give it a shot. Your thoughts please. Thanks guys, always good help on here!
 
I have to assume you are talking about the truck pan with the big cleanout cover. They are prone to leak if there is any way possible. A gasket inside will do nothing, just try again with everything straight and spotless clean, thread sealer, and your favorite gasket sealer. I like HondaBond, available at Honda bike dealers. Comes in 2 varieties, thick, and thin, I would go thick on that gasket.
 
Seems to me, a gasket on the inside would surround the bolts, keeping oil from getting to them, then bleed down the bolt to the outside. I'm still on the "try it" mode. Not convince that it won't help. Anybody else? Thanks cas3!
 
The parts book shows the gasket on the outside only. You are correct in that the oil can get to the shaft of the bolts, once there, there is no stopping it. I learned a while ago that putting a gasket on the inside will prevent the oil getting to the bolts. You still need a gasket on the outside. I think it would be possible but extremely difficult to get a gasket on the inside without removing the pan. I have cured the existing leaks by fitting a new gasket to the outside only. Put a couple of nuts on finger tight. Get some white thread seal tape (PTFE) Teflon. Wrap about 8 turns of the tape as close to the cover as you get. Then put a flat washer (don't use a spring washer) and then the nut. Don't over tighten it.
A couple of years ago a Boarder posted that he put some dome nuts with flat washers.
 
Thanks 69a, I feel the same way about a gasket on the inside. How bout this: Clean the area inside the pan real good with Xylene, then put small donut washers on each bolt, on the inside, glue them in place with a good gasket sealer, then do as you have suggested with the tape on the bolts. I don't want to remove the pan if I can get out of it! Thanks guys!
 
Are the donut washers metal? If they are you will get a slight advantage "point loading" which means you get the same pressure over a smaller area. If you are going to use sealer, use a non-setting sealer like Hylomar Blue, or the Permatex equivalent. Your donut washers will need to be 3/4" or less on the outside diameter because of the radius on the pan. The metal ring with the studs in it is 3/4" wide so. I have pan in the shed, I'll check it and get back....
Edited above
It may be worth trying a gasket on the inside. There is not much room between edge of the hole and the pic-up on the oil pump. It would be difficult if you're laying on your back! I would try using a light coating of high temp. grease on both sides of the gasket. it will save you trying to get the recess oil free, and help keep the gasket in place while you wiggle the studs back through.
 
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Kurt in NJ said:
have you tried copper or aluminum washers under the bolt heads?
Click to expand...

Kurt, this doesn't work, because they are studs with nuts, once the oil has got to the shaft of the stud it will work it's way down the shaft and through the nut just by the clearance in the actual thread.
It might be worth trying copper washers on the inside.
 
On my buddies 51 half ton I made the gasket out of 1/8" ruberized cork gasket material. I made the bolt holes slightly under sized for a press on fit and used blue RTV. Itnever leaked a drop. Tim
 
Great suggestions! Thanks guys, keep 'em coming! I took another look this morning and yes, might be difficult to clean all of the oil out from the recess under the inside ring. I like the idea of rubberized cork. Wouldn't need much of a sealer, if any. I thought of using a steel on one side and rubber on the other side washer, but oil could still seep under the steel. I knew you guys would have some great ideas!
 
Howdy boys, thought I'd give you the results so far. Yesterday I made 7 nitrile/cork gaskets, 3/4" diameter X 1/16" thick, with a 1/4" hole, and placed them over the bolts attached to the ring inside the pan. I then made another gasket for the plate, same material but 1/8" thick, and put it under the plate and attached the nuts to the bolts. I didn't use any stickem on the inside gaskets, but sprayed a light coat of Permatex Copper Gasket on the gasket under the plate. I did put a dab of Permatex 300 on each bolt before putting the nut on. I then added about a quart of oil and let it set for about 5 hours. No leaks so far. I will pressurize the system in a bit and see how it goes. OK, there ya go.
 
If it leaks this time, I'll remove the pan and clean it out so I will have a clean surface on the inside. Hope I don't have to do that!
 
It’s not uncommon to find the clean out flange of the pan warped due to over tightening those bolts trying to stop a leak. Even the ring gets warped. It was a good idea but introduces multiple leak culprits. Hopefully you have it sealed up. Pulling the pan probably introduces other leak areas at the rope seals so pick your battles.

JB
 
I hear ya. Figured it would be easier to do what I did with the pan in place, rather than pull it and have to start over with trying to seal it again. Didn't get to work on it today as much as I wanted, ( I think we should get those weeds away from the fence since it's so nice out today! Good idea darling, I'll get right on it!) but hopefully tomorrow will be better. :)
 
Howdy boys, well, so far no leaks! Guess we'll see how it goes when I fire it the first time. Standby........
 
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