Need PRO Help Identifying Oil Leak

jonwrong · Jul 28, 2013

Below are pictures of an oil leak I have. I had this leak and thought it was the oil pan. When I removed the oil pan bolts at the rear of the motor, oil came out with the bolts. I replaced the pan, gasket, and used RTV to be sure. Everything was surgically clean. Well, the leak is back in the same location.

I had an oil leak in the exact same spot two years ago. When I got the transmission off at the same time for a clutch swap, the rear main was not leaking. I replaced it anyway. I replaced the oil pan gasket then too. The leak seemed to go away briefly but is now leaking more than ever.

Finally, the heads were off the car two months ago (same time I replaced the oil pan). New valve covers and gaskets as well. I am out of ideas. I am getting a 2 inch spot on the ground every time I drive. Does anyone think it could be the rear main or something else? I have looked at the back of the flywheel through the hole on the driver's side; it looks clean.

It is wet across the entire bottom of the back edge of the block, including the parts that extend past where the pan bolts up.

302_Mustang · Jul 28, 2013

I would brake clean all the oil off an then put dye in the oil and drive around. After that check when the colored oil is coming from

MineralGreyGT · Jul 28, 2013

302_Mustang said:
I would brake clean all the oil off an then put dye in the oil and drive around. After that check when the colored oil is coming from

+1 one you can even get UV dye which is like 5.00 and use a UV light which makes very easy to find the leak.

WickedSnake00 · Jul 28, 2013

...or you can clean it and hit the area with white spray paint. That makes things more visible.

When you say you replaced the rear main, did you re-seal the retaining plate on the back of the block as well? That could be leaking rather than the rear crank seal itself.

EDIT: And have you checked any of the oil gallery plugs on the back side of the head?

jonwrong · Jul 28, 2013

WickedSnake00 said:
...or you can clean it and hit the area with white spray paint. That makes things more visible.

When you say you replaced the rear main, did you re-seal the retaining plate on the back of the block as well? That could be leaking rather than the rear crank seal itself.

EDIT: And have you checked any of the oil gallery plugs on the back side of the head?

Yes, I resealed the plate too. The leak appears to be in the same spot as before, and the car has new heads; as such, oil galley plugs seems unlikely.

SSG Pate · Jul 28, 2013

Yes from what you have explained it looks like you have a rear main seal leaking, Its time to pull off the tranny and put a new seal in. Let me guess you used the single lip Auto parts store Rear main? After looking at the seal offered from the parts store when I rebuilt my motor, I went and Got an OEM one. The lip on the parts house store and the spring is so cheap I don't se how it holds up at all.

jonwrong · Jul 28, 2013

SSG Pate said:
Yes from what you have explained it looks like you have a rear main seal leaking, Its time to pull off the tranny and put a new seal in. Let me guess you used the single lip Auto parts store Rear main? After looking at the seal offered from the parts store when I rebuilt my motor, I went and Got an OEM one. The lip on the parts house store and the spring is so cheap I don't se how it holds up at all.

I used OEM.

SSG Pate · Jul 28, 2013

jonwrong said:
I used OEM.

That's a plus, but for some reason its still leaking, unless something catastrophic has happened such as a block crack in which I highly doubt.

jonwrong · Jul 28, 2013

Damn these BBK headers. I wish pulling the tranny didn't mean pulling the K-member, passenger side header, and then tranny. Getting stage 8s on and off that header sucks.

MineralGreyGT · Jul 28, 2013

IMO instead of keep throwing parts at it buy the 5.00 UV die to be absolutely sure thats where the leak is.

SlowbaltSS · Jul 28, 2013

WickedSnake00 said:
...or you can clean it and hit the area with white spray paint. That makes things more visible.

When you say you replaced the rear main, did you re-seal the retaining plate on the back of the block as well? That could be leaking rather than the rear crank seal itself.

EDIT: And have you checked any of the oil gallery plugs on the back side of the head?

Or dump some high-visibility yellow paint into the crank case. That should mix with the oil real good.

MustangMatt96GT · Jul 28, 2013

Oil galley plug in the back of the head not tight and leaking? get an inspection mirror and flashlight and look at the back of the heads where the allen oil galley plugs are.

99_STROKED_GT · Jul 28, 2013

I have the exact same leak and I suspect its the rear main. I'm in the same boat with bbk LTs though so I'm going to wait to repair it until I rebuild or replace the trans

jonwrong · Aug 4, 2013

I bought dye and a UV light. Stand by...

yellow04GT · Aug 4, 2013

Did you replace the oil slinger properly? They will create leaks if not installed correctly.

jonwrong · Aug 4, 2013

yellow04GT said:
Did you replace the oil slinger properly? They will create leaks if not installed correctly.

I reused my original and put it back. I don't know how it could have been done improperly. Can you elaborate?

mikeracing · Aug 4, 2013

did your crank have any grooves from the old seal? if so the new seal wont seal and you need a speedy sleeve and normaly a special seal to match just my 2 cents

jonwrong · Aug 4, 2013

mikeracing said:
did your crank have any grooves from the old seal? if so the new seal wont seal and you need a speedy sleeve and normaly a special seal to match just my 2 cents

I wouldn't say there were grooves, but I could see where the seal used to ride. Can you elaborate or link to the speedy sleeve?

mikeracing · Aug 4, 2013

Buy National Redi-Sleeve 99157 at Advance Auto Parts

if i remember correctly you cannot use the repair sleeve with a teflon seal because there isn't enough give but for a normal seal they work well

yellow04GT · Aug 6, 2013

Someone please correct me if Iam wrong but I was thinking the issue with the oil slinger was not installing them, and installing them too deep. If you dont install them then dirt takes out your seal, if you bottom them out the oil slinger takes out your seal. Is this correct?

Need PRO Help Identifying Oil Leak

jonwrong

302_Mustang

MineralGreyGT

WickedSnake00

jonwrong

SSG Pate

jonwrong

SSG Pate

jonwrong

MineralGreyGT

SlowbaltSS

MustangMatt96GT

99_STROKED_GT

jonwrong

yellow04GT

jonwrong

mikeracing

jonwrong

mikeracing

yellow04GT

Top Contributors this Month

Recommended Communities