Sundevil64

I've had a chronic leak at the front of my oil pan. I have changed the gasket 3x. Still leaks. I have bought a new oil pan, still leaks. I am using the fel-pro blue one piece gasket.

The front portion that meets with the timing cover seems awfully thick. The application is a 70 corvette motor (350). Should that be the "thin" version of the front seal?

TopLess62

You are sure its not coming from the crank seal in the timing cover? Use a clean Q Tip to wipe off above the oil pan and see how oily it is. Just a thought...

knight37128

Sounds like you need a sleeve.

TopLess62

Or just the seal in the cover, which isn't too bad. You still have to take the balancer off though....

Plasticman

Fel-Pro blue 1 piece gasket # FPP-1880 is the thick version for 1975 and newer engines.

Fel-Pro blue 1 piece gasket #FPP-1885 is the thin version for the 1975 and older engines.

Depending on which oil pan you have will determine which gasket you should use (not the engine block or timing cover - they are the essentially the same for all years, as far as which gasket to use).

There is a method for measuring the depth of the oil pan depression at the front to determine which pan you have. The older pans will have an opening of 5 1/2 inches across, and 2 1/4 inches high, and this will use the 1885 gasket.

If the front depression is about 6 inches across and 2 1/2 inches high, it will use the 1880 with a thick front seal for the 75 & newer engines.

Plasticman

AZDoug

And if your car has a service replacement pan, it is probably 3/8", no matter what year.

Doug

JohnZ

Any GM replacement oil pan manufactured after 1975, even if specified for a pre-'75 application, requires the "thick" front seal, which is usually included in the box.

Flip the pan upside-down on a flat surface without the gasket and measure the height from the flat surface to 12 o'clock on the sealing flange; if it's 2-1/4", it takes the "thin" seal - if it's 2-3/8", it takes the "thick" seal.

Bluestripe67

Let me add, when you bolt the pan and cover back on actually use a torque wrench and set the 1/4-20 bolts at 80 in. lbs and the 5/16-18 bolts 65 in. lbs. By not overtightening you will prevent squeezing out the gasket and dimpling the bolt holes, common mistakes leading to more leaking. Dennis

lovevettes

I just bought a one piece Felpro PermaDryPlus [ blue one ] for my '64 Vette and the part number is OS 34509 T ---Thin seal.

I just went on the Summit site -
FEL- OS34509T= thin seal
FEL- OS34510T= thick seal

By-the-way I don't think you can over tighten [ squoosh] these they have a piece of hard plastic where the bolts go thru.

I put one of these gaskets on my '60 Vette two years ago and it stopped all the problems.

jfp1

Make sure you are not missing the bolt out of the front of the block by the fuel pump. If the bolt is not there it will leak oil around the front of the engine and look like a gasket or seal problem. The bolt needs to be short enough to block the hole but not too long or it will lock the fuel pump pushrod.

Sundevil64

Thanks guys for the tips. I will have to pull the pan and measure it.

I have replaced the seal on the timing cover, still leaked. I replaced the timing cover, still leaked. I replaced the balancer and put the sleeve on, I checked this the other night to make sure I wasn't mistaken, still leaked. I replaced the pan, still leaked. I put some of that stuff in that you can trace a leak and itl appears to come from the seal area where the pan and the timing cover leak.

Oh yes, almost forgot I torqued the thing as the service manual states every time evenly so as not to warp the pan.

I think I am becoming a little warped. Hopefully, I will have time to work on it Saturday. Sunday is taken of course.

Ron Champe

I too use the one piece gasket with great results. But..... I also "always" put 4 small dabs of the correct silicone at each of the 4 corners of the gasket just where the gasket rolls up at the front and rear of the pan. I install the pan while the silicone is wet and just tighten the bolts enough to hold the pan and flatten the silicone. Then, the next day once the silicone is dry, I torque the pan bolts. Never had a leak.

Sundevil64

Yeah. I did that too. I think I have the wrong gasket.