Every once in a while, when we start up the 2003 Discovery II it seems to leak oil very acutely. This has happened several times. I keep clean cardboard under the truck at all times to monitor the various fluid leaks.


From time to time, right after start up, the motor seams to leak at either the front or rear seal. It leaks for a couple days, in decreasing amounts, and then stops. It has done this from both the front and back of the engine. It appears to be at the front or rear seals. It is not chronic. It always stops for days, sometimes weeks at a time. I have 2000 miles on my last oil change and it is barely below the full mark.


Is there something, say for example crank case pressure, that would cause this engine to leak, then stop, occasionally. It is not a consistent leak at all. It's more annoying than anything else. I've managed to get all of the coolant leaks sealed up, and this is the last oil leak I have to wrap up before I will consider the truck to be confidently reliable.


Suggestions?

 

What oil weight do you use?

Very small, come-and-go leaks can be halted with a different oil weight. 15-40 is common. I don't leak so much, so I go a bit lighter for cold start up.

I know it sounds odd. If it's leaking it's leaking, and it shouldn't.

As it leaks at start up sounds like something is getting up to operating temperature, and sealing something up.
If you really wanted to track it down, you could get some uv dye. And give the engine a really good degreasing.

 

Up front I can see exactly where it's coming from. Front cover seal. Back end it is leaking at the bell housing. I'm think RMS, but cannot see for sure, and dye wouldn't help.


I'm just wondering why it leaks once in a while, but never consistently.

 

Ah, fair enough.

If you arnt using 15-40 Dino oil, try it.

As I say, sounds like things are expanding at operating temperature and sealing little gaps, or just pushing that gasket enough to stop the flow. Although usually, as things warm up the oil thins and that's when drips start.

Answer - dunno....

 

Rank guess here.

Your oil pressure release valves are not perfectly sealed so as it sits the column of oil above the oil pump and filter slowly leaks back to the oil pump, and seeps past the front seal.

Rank guess.

 

Have you checked the rear manifold seal? Sometimes leaks and flows down to main seal area, same in front.

 

I cannot get great look at the back, but from what I can see. it's not leaking down from the manifold. It looks like it's coming from the rear main seal. I can clearly see the front leak. It's from the front cover seal. No oil above that.

Just seems strange that it comes and goes.

 

I haven't seen oil touch the ground since I went to Rotella 15W-40. Worth a shot.

 

Changed over to Rotella 5w-40 full synthetic on my last change. I love the way the engine runs, but I may go to the thicker oil for the warmer weather on my next change. Is the 15W-40 that you use the dino oil, a blend, or full synthetic?

 

If it's the front crankshaft "seal", it's an easy fix. If it's the front cover "gasket", it's a little more involved. You need to clean/degrease your motor and watch daily by looking under and all over your motor with a flash light and see where your leaks are coming from. Right now it seems you are guessing. Changing oil weight isn't going to fix oil leaks, maybe slow them if your lucky I guess....MO