Rear main leak

J

jetmek

Senior Member
Would this missing plug be a culprit ? Everything else looks good. No excessive end play. Gasket changed already. I can watch it run down the cap from the rear.
 

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Assume you are aware that the small welch plug is missing from the end of the drain hole oil passage. If not, that is why you have a leak. Replace the plug and your problem should go away. Did you remove it or was it missing when you pulled the cap?
 
I think I have the same problem. I just found an allen screw on the floor under the engine and lots of oil on the floor after running. Where does this plug go and how do I get at it?
Thanks
Warren
 
wuga said:
I think I have the same problem. I just found an allen screw on the floor under the engine and lots of oil on the floor after running. Where does this plug go and how do I get at it?
Thanks
Warren
Click to expand...

The plug appears on the INSIDE of the oil pan. The tube you see follows the rear wall of the oil pan down below oil level. You have to drop the oil pan to get there from here.

Just like when the tube breaks off or falls off, a missing welch plug CAN be a source of oil leak - especially if the square cork gasket is not sealed against BOTH pan and semi-circle seat of the bearing cap.

The square gasket acts as a sort of "knife edge seal" against the semi-circular edge of the pan.

Most will use something like Permatex No. 2 for adhesion between cork and semi-circle bearing cap seat. And carefully fit the square cork to the bearing cap - trimming carefully and SQUARE at the ends where the cap meets the block. Maybe leave it a little proud at this point to take advantage of a compression between end of cork and the block. Not too much though lest the compression lift and break the seal of cork and cap.

A lot of engine pan gasket sets have a "square protrusion" at this point to mirror the semi-circular square cork seat.

Joe K
 
The tube, and the plug, keep any air pressure in the pan from blowing oil out the rear. There should not be very much pressure in the pan but it depends mostly on how much blowby you have and how clear the oil filler tube and cap are.
 
Thank you very much for the replies. Thursday I dropped the pan and everything was just where it was supposed to be. Better safe than sorry. But the rear pan gasket looked suspicious so Friday I talked to Bert's who built my engine some 10 years ago, got some good pointers, cleaned all the surfaces and installed a new gasket set. This would have been easier on an engine stand but I finally got it back together. Those four pan bolts at the front are miserable to get at passed the tie rod and cross member. Removed the rad hoses and jacked the front of the engine up about an inch. Fresh coolant and oil and ran the engine about 20 minutes. No obvious leaks. We'll see.
Warren
 
Some people use socket head machine screws at the front so that a long socket wrench can be used. Others put slots in the heads of the machine screws and use a screw driver. I don't think it matters which way you turn the wheel but check which works best for you.
 
Bow goose Wednesday morning 3 AM ...

Breaking news Punjab, India, 0h three dark thirty AM ... Elephant, Rasheed mauls washing machine at local laundromat. More news at eleven!
 
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