Oil leak

[Ted G]

After about 800 miles, I've noticed a small oil leak which appeared to be coming from the back of the oil pan. Since it was time to do an oil change, I decided to also change out the oil pan gasket. Not a small job, but a dirty one for sure.

This past Sunday, I drained the oil and removed the filter and waited till Monday to remove the oil pan. This lets the pistons, crankshaft and block drain oil overnight into the pan. Monday I removed that pan and really was not able to pinpoint the leak, but I believed it was coming from one of the bolt holes that maybe wasn't sealing so well. That bolt hole was close (two away) from the back of the pan. I was sure this was an oil pan leak and not a rear main seal leak. Here is a couple pics of my Aviad oil pan and the rotating assembly:

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I installed a new 4 piece FelPro gasket (recommended by Avain) and my engine builder with Permatec gasket RTV and let it sit for 24 hours to cure. This morning I added the oil and filter and started her up. She ran for about 15 minutes to get fully warmed up. I went underneath whalla! No leaks in the oil pan.

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I go back out about a half hour later to double check and I find a tiny leak. Looks like it is not coming from the oil pan but from the front of the block plate. Here are two photos:

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My thoughts is this may be the rear main seal. Thoughts?

Thanks in advance for your thoughts.

[rich grsc]

I wish I had a dollar for ever "my rear seal leaking?" ;) Oil runs down hill, and from front to back. Start looking at the top of the motor, also if the rear seal leaked, that oil would likely be on the other side of the dust shield

[Ted G]

I wish I had a dollar for ever "my rear seal leaking?" ;) Oil runs down hill, and from front to back. Start looking at the top of the motor, also if the rear seal leaked, that oil would likely be on the other side of the dust shield

Thanks Rich

[boat737]

Yup, when I thought it was my "rear main" leak, it wasn't. It took me two weeks to find it, but it was the forward portion of the DS valve cover. That leak managed to have the oil travel all the way from the front of the valve cover down to the bottom of the bell housing. I replaced the valve cover gasket, and that fixed the problem.

[Mike.Bray]

I would put (one piece) rear main seal very low on the list. It's basically a shaft seal that fits tight as snot in the block.

I had a small oil leak at the rear of the engine coming off the far edge of the block. Turned out to be from the valve cover, the oil was running downhill and wicking over to the edge of the block before it dripped.

[Ted G]

Thanks guys..... I'll get my light out and inspect further.

[brewha]

I’ll be chasing a small oil leak soon also. I going to start by retorquing the valve covers and the oil pan to see if I can stop it before replacing the gas kits. I got a small leak in a power steering line also that’s driving me nuts.

[CraigS]

Also carefully check the rear china wall of the block to underside of the intake. When looking for leaks do the best you can w/ plenty of light and an inspection mirror.
https://www.homedepot.com/p/Husky-Lighted-Inspection-Mirror-80556H/306093331
But my final test is to rub the pad of my finger tip over the suspect area. Get the light angle just right and the slightest bit of dampness on your finger is very obvious. That works fantastic on brake lines too.