Is this a 4.0 engine?

[AndyG]

Let me say this as a TJ owner and as a person that works with physical products.

there are some things that are just inherent with some designs .

Rms leaks go with 4.0 engines .

Most of the ones I've seen just aren't that bad.

Things don't have to be perfect to be great.

I've seen people go after that issue and create bigger problems.

It will leak, but it will do it while it's running 250 to 300 thousand plus miles.

They typically don't leak enough to even require additional oil in between service intervals.

I would not stress over that and I wouldn't let that prevent me from buying one.. one thing if something leaks oil that means that it's been running and it has some in it..that's a good thing .

 

[AndyG]

Every engine made has quirks . Ford's legendary 7.3 powestroke eats cam position sensors up.

Even some Ferraris burn oil.

I run high mileage oil occasionally as it has seal conditioners , and leave rear main leaks alone .

The 4.0 has way more good than bad.

The rarest thread on here is "my 4.0 died".

 

[JDS123]

My RMS is leaking again. It stopped leaking for about 2.5 months after I had the engine out and completely resealed (including a new RMS). I've learned to live with it. Just can't win with these things...

 

[mrblaine]

My RMS is leaking again. It stopped leaking for about 2.5 months after I had the engine out and completely resealed (including a new RMS). I've learned to live with it. Just can't win with these things...

Precisely why I give a here to the street warranty on them when I do them. I have no problem doing good work. I have a giant problem when I can't do anything better to prevent a predictable outcome. Some last, some don't and there is nothing I can do to change that and I won't be punished for it.