Oil pan leak

[Gerry P.]

I replaced the oil pan gasket on my '57 to correct a small drip and now have running drip. The original gasket had considerable silicon seal applied to both the side strips and front and rear seals. I replaced it with the one piece molded gasket and following instructions, put a little RTV hi temp silicon seal on the corners of the block where it meets the timing chain cover and the rear main cap. When I started the engine, oil was literally dribbling out from the bottom of the pan where it meets the timing chain cover. Frustrated, I took the pan off and replaced it with an original style 2 piece cork gasket with rubber end seals. For the second installation, I put RTV silicon on the front & rear corners (where the rubber seals meet the cork gasket) and a small bead on both sides (front and rear) of the front seal and on the pan itself where it mates the front seal. I placed the cork strips on first with the rubber seals second (gasket between seal and block). When I tightened the pan bolts (torqued to approx 12-15 ft lbs) the cork gasket on the front corners pushed out a little. Not sure if this was from too much silicon or something else. Started the engine and oil again started dribbling out from front of the pan where it meets the timing chain cover. It drips off the bottom and can't tell if that is where the leak is or if it is up higher and is running down to the lowest spot before exiting.

I'm trying to determine if there was a flaw in my installation process or if it is possible the timing chain or pan are bent slightly which will not permit a seal. Maybe I used too much sealant which prevented the rubber end gaskets to improperly seat?

Suggestions appreciated.
Regards,
Gerry Phillips

[Dan P.]

Re: Oil pan leak

Put A straigt edge on the pan rail and you will see that were the bolts are the rail is raised up . You will have to put rail on a piece of wood or edge of the workbench and flatened the rail back. What happens is when you tighten the pan it raises the rail . So you tighten it some more raising it up more .Thne you put a new gasket on and the only part of the gasket that is compressed is at the bolt holes .
When you put the pan back on lightly tighten it and let it set over night and then finish tightening the pan so you do not squeeze the silcone out but actually compres it after it has set.

[Joe L.]

Re: Oil pan leak

I replaced the oil pan gasket on my '57 to correct a small drip and now have running drip. The original gasket had considerable silicon seal applied to both the side strips and front and rear seals. I replaced it with the one piece molded gasket and following instructions, put a little RTV hi temp silicon seal on the corners of the block where it meets the timing chain cover and the rear main cap. When I started the engine, oil was literally dribbling out from the bottom of the pan where it meets the timing chain cover. Frustrated, I took the pan off and replaced it with an original style 2 piece cork gasket with rubber end seals. For the second installation, I put RTV silicon on the front & rear corners (where the rubber seals meet the cork gasket) and a small bead on both sides (front and rear) of the front seal and on the pan itself where it mates the front seal. I placed the cork strips on first with the rubber seals second (gasket between seal and block). When I tightened the pan bolts (torqued to approx 12-15 ft lbs) the cork gasket on the front corners pushed out a little. Not sure if this was from too much silicon or something else. Started the engine and oil again started dribbling out from front of the pan where it meets the timing chain cover. It drips off the bottom and can't tell if that is where the leak is or if it is up higher and is running down to the lowest spot before exiting.

I'm trying to determine if there was a flaw in my installation process or if it is possible the timing chain or pan are bent slightly which will not permit a seal. Maybe I used too much sealant which prevented the rubber end gaskets to improperly seat?

Suggestions appreciated.
Regards,
Gerry Phillips

Gerry-----


First, make sure that you are using the correct gasket set. GM replacement oil pans for 57-62 Corvettes available after about 1975 used the 75+ front seal. The 75+ front seal is THICKER than the original 57-62 oil pan seals. So, if you use a 57-62 gasket set with a replacement oil pan, you will end up with a big leak at the front oil pan seal. Curiously, this appears to be just what you have.

To confirm which pan you have, place the pan upside down on a flat surface such that it is resting on the oil pan rails (with the oil pan bolt holes "flattened" as Dan described). Then, measure from the flat surface to the apex of the front oil pan seal radius. If it's an original pan, the measurement will be 2-1/4"; if it's a replacement, the measurement will be 2-3/8".

[Gerry P.]

Re: Oil pan leak

Dan & Joe, thanks for the replies. I need to pull the pan off, staighten the rails if necessary and check the size of the pan per Joe's suggestion. It may be next week before I can get to it and will report back on my findings.
Regards,
Gerry

[Gerry P.]

Re: Oil pan leak

I pulled the pan off and it measures 2 3/8" so I must have the replacement pan. This does raise a question for me, since the newer pans have different radius (where the pan mates with the timing chain cover), should the engine also have a newer timing chain cover to match the deeper radius of the pan. Or is the timing chain cover the same, just a gasket diff? I guess my question is, can I assume a '75 & newer pan gasket will fit the existing timing chain cover? If so, that is an easy solution although it has been frustrating getting there.
Thanks
Gerry

[Joe L.]

Re: Oil pan leak

I pulled the pan off and it measures 2 3/8" so I must have the replacement pan. This does raise a question for me, since the newer pans have different radius (where the pan mates with the timing chain cover), should the engine also have a newer timing chain cover to match the deeper radius of the pan. Or is the timing chain cover the same, just a gasket diff? I guess my question is, can I assume a '75 & newer pan gasket will fit the existing timing chain cover? If so, that is an easy solution although it has been frustrating getting there.
Thanks
Gerry

Gerry-----


With respect to the oil pan sealing surface area, the timing covers did not change. So, any 55+ timing cover will work with the oil pan you have. All you need to do is to make sure you use the correct gasket set.

By the way, the Fel-Pro 1 piece gasket for your application is OS34510T.

[Gerry P.]

Re: Oil pan leak

Thanks Joe - I'll put the later gasket on and hopefully my problem will be solved.
Gerry

[Gerry P.]

Re: Oil pan leak

Just finished installing the 75+ gasket and test drove the car around the block. Not a drop of oil showing up on the bottom of the pan. What a difference the correct front seal makes!!!! I really appreciate everyone's advice - just wish I would have had it a few days ago before going through 4 pan gaskets trying to stop an oil leak the size of a river.

Now phase II of the project begins in cleaning the bottom of the car from where the radiator fan blew the leaking oil. I'll be accepting auditions for anyone out there wanting to come over and give me an hour or so demonstration on their best practice method of cleaning up oil. I'll even give a case of beer to the person doing the best job.
Gerry