Did a successful Duraspark II conversion on my 86 f150 two weeks ago so now its time to tackle my oil leak.

I know that the front of the trans is where the rear main seal is, and that it is a dreaded job to do. Before I even think about throwing the $500+ bucks at it, is there any way I can verify that this is the source of my leak? What other gaskets would make it look like the leak was at the rear main seal?

Looking over my engine (which isn't too caked with oil since its only got 100,000 on it) the only oily wet spot I can find is where the engine and trans meet. All other visible parts of the engine have dried oil on them. I have added over a quart of oil since I changed the oil 1,000 miles ago, so the leak is a steady drip.

What I know about the truck is that it sat for a majority of three years at the shop where I bought it from, only being started and used occasionally. After I bought it, I pretty much hopped in it and made a 7 hour drive across the state of Washington and have been driving it daily ever since. In that time the leak has gotten noticeably worse.

If I was only using this as an around town work truck I wouldn't worry about this kind of leak. However, I will be using this truck to commute to school which is on the other side of the state and don't want to lose the rear main on that long drive, so I want to have it fixed. I don't have a shop or the necessary tools for this kind of a job either, so its something I will have to pay to be done.

Thanks for the input.

 

Valve cover & intake manifold gaskets can leak at the rear of the engine and then down between the tranny and engine and then out, making it look like a rear main seal. You need to climb up in the engine compartment and look behind the engine as best you can. If you see anything wet you may have found it.

The valve covers might seal if you gently torque the bolts down. GENTLY as the torque spec isn't much. But, if the truck sat for years the gaskets may have dried and, therefore, shrunk, so it may not work.

Assuming the engine is a V8 the intake manifold is supposed to seal at the rear with another cork gasket. But, if it dried/shrank there's probably nothing that can be done short of pulling the manifold and installing new gaskets. However, you can check the bolts to ensure they aren't loose.

Oh yes, please let us know what engine you have when you ask questions. The easy way is to go into User Control Panel and put the info in your signature so it is always there. But, there are some geeks out there that have the sig's turned off so that doesn't always work.

 

Huh? Who? Where?

 

Sorry I forgot to mention the engine and trans specs. It has the 300 inline 6 with a 4 speed transmission that has compound low.

Last night I placed a white sheet of cardboard under the truck to get a good idea of how much and where it was leaking oil. The normal spot under the rear main had a spot as well as three very small ones from up front. I did park with the front of the truck facing downhill so tonight I will reverse that and see what happens.

 

I'm not familiar w/the 6, but would think its valve cover could easily leak at the rear and cause rear main symptoms. However, forget what I said about the intake manifold as it doesn't apply on a 6.

Also, bear in mind that oil will blow back when going down the road so it could be further to the front.

 

If you can do a DSII conversion, you can fix a rear main seal leak. Like these guys already said, look around the top of the engine first. If you don't have tools, go buy some, you'll need them anyway if you plan to drive an older truck everyday. Might as well get familiar with the truck and do stuff yourself. It's not as hard as it sounds. Do your research online, buy a repair manual, prepare yourself with knowledge, get the parts, and do the work. For the amount of money you spend on having someone else do the repair, you can buy a set of basic tools and buy all the parts needed and do it yourself. A rear main seal is an afternoon job if you're prepared for the task at hand.