The Stovebolt Site Forums The Shop Area Engine Shop 250 Oil Leak

I have a '66 c10 250 automatic transmission. The engine was replaced a year or so ago with a long block - new gaskets. It now has 5k on it and has an oil leak on the rear of the oil pan. I anticipate the bolts need tightening. I know that I will need to drop the starter - but there is also a cover where the transmission meets the engine - and I believe that will need to come off as well to tighten all the pan bolts. I have checked the valve cover bolts and tightened some of those. I have also checked the oil sending unit and that is not leaking. What else should I be aware of? The oil drips off the bottom of the pan and the transmission cooling lines immediately after running the truck. Advise please - Tim-o

You do not have to remove the starter. You can remove the flywheel cover & it will give you a beter look at it. Just snug them up. If you tighten them too much it will distort the pan & make it worse.

Well, that's good news that I can leave the starter on. I have snugged everything else up - so - with your kind advice - I do the same under the flywheel cover. The wife's going away this weekend with her girlfriends. It's shaping up to be a fun weekend in the garage for ole Tim-o. Thanks for your thoughts.

Ok - I finally got time to take a look at that oil leak. I removed the transmission cover and there was some oil accumulated there by the hole - so I figured that was the issue at hand. I removed the long bolt for the starter (inside one) and loosened the second bolt so I could get to all the pan bolts. Some were slightly loose so I snugged them up just as recommended previously. I bolted the starter back up, cleaned all visible oil off the transmission pan, oil pan, starter and automatic transmission fluid lines. I put everything back together, started it up and let it run in the driveway. The leak continues but this time the leak is much smaller. It now seems to be dripping off the center of the starter. The oil pressure sender is not leaking and nothing else is visible from the top of the engine. Ideas please.... Tim-o

The rear main seal could the problem , it could be throwing the oil on to the starter gear which drips off where you see it. There is no other oil source around the starter other then the sender. Check higher up, the side covers are tough to seal and I have had a tough time with valve covers leaking from the rear and running down the bell housing and dripping off the dust cover. After market chrome covers are really hard to seal up.

When sealing the covers, very few sealants will stick if oil is present. Use brake cleaner or paint thinner to clean and dry any sealing surface.

joe

Joe -interesting point about the ring gear throwing oil. I considered the rear main seal, but wouldn't the oil be visible coming through the hole in the transmission cover too if the rear main was the problem? I'll take another look at the side covers and valve cover too. I appreciate your help and advice.

Tim-o

Yes, the dust pan should have oil in it if its really bad. How about the dipstick tube? I have a spare 250 block downstairs, I will look it over and see if I can see anything you might be missing.

Joe