need some insight. last january i took my 68 I6 in to my local mechanic and had the rear main seal replaced in order to fix the oil leak ive had ever since i got the car. a few weeks ago i took my car into a local mechanic who specializes in vintage mustangs. one of the things he noticed is that it was still leaking from the rear main seal. so i take it back to the place who had fixed it back in january, and as the fix was under warranty, they replaced the rear main seal again. well i get my car home and i see a trail of oil spots leading up to the spot i parked my car. it seems to be leaking worse than before. I'm honestly not sure where exactly the rear main seal is in the car, but if you open the hood and look down you can see oil (see the atatched pic. Im refering to the black part at the bottom of the engine. the marks on the enigine itself are old.) I dont think the place in the pic is the only place im losing oil, becuase theres quite a bit leaking and that particular spot doesnt look all that thick with oil. Also, dont be thrown off by the puddle of oil on the ground, that is an accumulation of three years worth of oil leaks.
So my questions are, where is the rear main seal, and is it near what has oil on it in the picture? and is there any other reason i could be springing this leak other than bad workmanship? and any other advice?

[IMG]local://upfiles/16347/19E886B9E4F340E4B32E8753D31BC522.jpg[/IMG]

[IMG]local://upfiles/16347/4AE8A7709DC047F88F925185B688CAA9.jpg[/IMG]

 

The rear main seal is located at the rear of the engine where the transmission stabs into the engine. It's at the end of the crank in the rear. It appears you are still leaking there.

 

over time a seal rubs on one part of the crank, this can create a groove that allows oil to seep past the seal on newer engines with a neoprene seal. The way to fix it right is to pull the cank, have it ground undersize, replace all bearings and put it back in. The seal will then have a fresh area so run on and no grove. Also the neoprene seal can be installed backwards and it will allow even more oil to come out, but it would be simliar to having no seal in there, oil would pour out while it was running.

On older engines there may be a rope seal, they will leak some almost no matter what you do, but if you have a rope seal you gotta pull the crank out of the engine to fix it properly. You cant push a new one in there with the crank still in like you can with a neoprene seal.

I havent been inside an I6, so I dont know what seal it has, but it sounds like you need someone who knows how to fix it right. Not saying your local mechanic is incompetent or lacking knowledge, just that some older vehicles have quirks that require someone who has worked on them more than just plugs, wires, and engine swaps.

 

I know that its not the rope seal wich they used i believe on the V8s, and Im pretty sure the particular machanic who has been working on my car is incompetant. Thanks for the information.