Most Likely Oil Leak Source(s)?

[FL-Frank]

Following a complete professional engine rebuild 3 years and 17K miles ago, my '72 T has recently sprung what I would describe as fairly significant oil leak(s).

There are a couple of small puddles (maybe 3"-4" in diameter) of oil on the garage floor within an hour of shutting down after driving it. Although it still leaks some while just sitting idle in the garage, the amount of oil on the floor is not as significant as occurs just after driving.

I've placed newspapers under the rear of the car to get an idea of where the oil may be coming from. The oil spots on the paper are located directly under the center of the engine, and also to the right of center, in-line with the right rear wheel.

Before taking it to my mechanic for a reseal, I'd like to hear opinions on the likely source(s) of the leak(s).

Thanks,

[M491]

I have the same problem, and am very interested in hearing the advice you get. Thanks for asking this question!

[FL-Frank]

Possibles:

Thermostat and/or oil return tube. Oil line leak from the case. Check your drain plate/crush washers.
The thermostat is at the back of the engine and does require a bit of work to get at but it's not a hard job.
Hopefully it's not the front seal.

That's all the guesses I have. Good luck!

Tom

Thanks Tom!

[Neunelfer]

My thermostat is leaking and basically exhibiting the same signs. Hard to detect as the oil runs down the spine of the engine and then drops.

[911pcars]

The oil pressure sending unit is next to the engine thermostat. Another source. Take a look.

Sherwood

[kentf14]

I was once told by someone that a leaky oil return tube can be fixed (sometimes) by rotating it a little. This must re-seat the O-ring?
Does anyone have input on this technique? I've also been told never to rotate the tubes....:-)
What does practical wisdom say regarding this?

Cheers
Kent

[304065]

Here's what I would check, in order of priority

If your 72 is MFI, check the MFI oil supply hose, this has a banjo fitting on one end and a straight fitting on the other. These often crack and leak like a monster, over the back of the engine and around the gearbox.

Oil pressure sender threads through the banjo fitting and into the case with a couple of aluminum crush washers to seal it up, that's an easy place to check.

Even if not MFI, you should still have a pressure sender up there to check.

Engine oil thermostat seal could be leaking, harder to remove it but possible with engine in the car.

Cam oil lines, inboard and outboard end. If you have Carrera tensioners check those too.

Down below, S-hose connection on the oil cooler.

Scavenge port connection in the side of the case, hard to check it because the port heat exchanger is in the way, but you can do it.

Finally, the case parting line.

A good way to check for leaks is with a flashlight, you should see visible drops in various places. Once you have logged in the location and number of those drops, wipe everything clean. Don't use Simple Green, I would use something like denatured mineral spirits on a clean rag. Then get yourself one of those travel bottles of baby powder and use it to create a FINE mist of powder droplets in the places you inspected. Let the car sit for a couple days and see where the powder is displaced, there's your leak. Then clean it off again.

A few hours of searching is worth the time vs. taking it to a professional, I would exhaust my own remedies before incurring the expense and risk of taking my car anywhere.

Good luck!

[Zithlord]

Could also be one or more of the 3 O-rings that seals the oil cooler to the engine.

John

[bliebler]

I thought my oil cooler was leaking. It turned out to be warped intake valve cover. there is allot of air blowing around this area and it blows oil off a clean case deposits it somewhere else. Also, check rocker shafts. I had to crank mine pretty tight even with using the rubber O rings. don't panic yet!