I have a 2005 Ford Ranger FX4 4.0. I can smell burning oil after I've been driving awhile and then stop. Mechanic said it is a rear main seal leak. This has been going on for 5 years. There is no oil dripping on the driveway and I go 5000 miles between oil changes and it burns about 1 quart in that time. It is not getting worse. How can I check to see for myself that the rear main seal is leaking? Is it something to be concerned about? What will be the approx cost to replace? Many thanks from the Big Island of Hawaii.

 

Rear Main Seal is on the crank shaft between flywheel/flexplate and block(engine)
So to get to it you need to remove transmission, take off flywheel/flexplate and then pull out the old one, inspect the crank for damage, scratches, and then replace with new seal, if scratched then you need to use a sleeved seal kit, new seal or kit is not expensive, under $20
Getting to it is the hard part, lol, which is why you repacae the rear main seal anytime transmission is out for any reason

Failing Rear Main seals leak QUARTS, there is a rear crank bearing just inside of the seal and it PUMPS OUT oil like crazy, seal holds this oil inside the engine, same for Front Main seal
You would need to add oil constantly and there WOULD BE oil under the truck if you parked for even 1 minute, constant drip of oil

So if this has been going on 5 years it ain't a main seal leak, if you can look inside bell housing it should be coated in oil, if you pull out starter it's nose and gear would be full of oil

Picture of rear main seal here: https://www.ranger-forums.com/4-0l-o...4-4-0l-128006/


If you go here and then to Post #13 you will see picture of the jackshaft plug on the back of the 4.0l SOHC engine, its being removed: https://www.explorerforum.com/forums...cedure.316471/

This plug could be leaking, it wouldn't leak much at all, and never heard of these leaking, but it would leak into the bell housing area so mechanic could mistake that for rear main seal since on ANY other engine main seal is the only place oil could come from when found inside bell housing

 

I, as well, was told that I may have a rear main seal leak or an oil pan leak. Not enough oil loss to be a rear mail seal issue. Thanks!


Wiped clean this area and a week later this is the oil that has collected at the back of the motor.

Different view.

 

We to the forum thing. Hoping to find part numbers for good rear main seal and torque converter seal for my 05 Ford ranger 4.0. Thanks in advance

 

Welcome to the forum

Go here: https://www.ranger-forums.com/genera...discussion-15/

On the left you will see "+ New Thread", click on that, then you can ask your question in your own thread
Do as you did above, include Year And Engine model, 2005 4.0l

Posting a new question someone else's thread is consider "bad manners", lol
There are no "manner police" but most people will not answer a new question unless it was from the original poster of the thread

Forums are set up that way so you can find answers to common questions easier, if every post about rear main seal was in one thread there would be 10,000+ posts you would have to go thru to "maybe" find an answer for 2005 4.0l
So more practical than "manners" but sold as a "manners" thing