'78 LeMans rear main seal HELP!

[Uncletruck]

I have a '78 LeMans that is in near showroom condition, and all original with 53,000 miles. It has the Buick 3.8 V6, it runs perfectly and gets good gas mileage. The engine has one issue though, that has been ongoing. I am currently on my third rear main seal replacement in the last 700 miles. All the seals have been replaced at the same shop, and they usually know what they are doing, but this is getting ridiculous.

The first time around they replaced the seal with the stock rope seal, and this leaked, or should I say gushed oil after about 200 miles. They put another rope seal in. That one lasted about 300 miles, same thing happened. This last time they thought they had it licked by putting in a Fel-Pro two piece rubber real. Well, 200 miles later, the bottom of the torque converter cover is soaked with fresh oil again. This past time I looked at the seal journal on the crank when the bearing cap was off, and it was smooth with no nicks or burrs, so I don't think the seals are being torn up.

The shop has put tracer dye in the oil to try to locate the leak, but it seems it is just slung all over the back of the flywheel and bottom of the block. There is nothing from above to indicate a leak from the intake manifold or valve covers, those are all dry.

Before I see the shop again for the forth time tomorrow, does anyone have any suggestions on what to tell them to look for?

Thanks for any help

-Mark-

 

[maliburacinfreak]

are they replacing the pan gasket when they replace the seal? that should be a given but ya never know with some shops.

 

[Chevyman85]

Those rope seals typically leak a little oil but that sounds excessive. Either way with a 2 piece rear main you should expect a small amount of oil leaking out. As long as they arn't charging you keep going back till they get it right. My buddy had a similar problem with his 460 in his truck. Ford uses the same seal on their big blocks.

 

[Uncletruck]

Thanks for the help. I brought it back and they put it on the lift, the mechanic who worked on it swore it wouldn't be leaking from the rear seal. We looked at it and the oil is coming off of one side up by the starter, and he said he suspected that it was just from the oil pan gasket (which was new) not sealing right on the corner. He said he would take care of it by the end of the week, (They do guarantee their work) I'll hope for the best

-Uncletruck-