I’ve got a 2010 4.0 sport with just over 220k kms on it.

It has a slight rear main seal leak. It has never dripped on my driveway or gone low on the dipstick. I just noticed it when I was working on something else.

I really love this truck, so I’ve been learning to do my own maintenance. I want to keep it on the road for as long as possible. The rear main seal is really out of my wheel house though. I could afford to get it fixed, but I is still expect a hefty price tag. This has me flip flopping on pulling the trigger. Some people say leave it alone, some people say just use a stop leak. What does the ranger forum say? In terms of engine longevity, should this be a priority?

Knock on wood, there’s nothing wrong with my truck, except for this little leak. It runs great. What should I do?

 

Not sure if this helps you but I've been chasing an oil leak on my 01 4.0. I had it evaluated and was told it was valve cover gaskets, had them replaced and still leaking. My suspicion was and still is the rear main seal but I don't want to drop the trans unless I need to have the trans replaced or motor pulled for whatever reason. The cost of valve cover gaskets replaced was a wash, I paid $625 in case you wanna know

 

Interesting. Experiences like yours are why I’m leaning towards just leaving it. Some guy on reddit said he had a rear main seal leak fixed and it started leaking again within a year. I think i’ll continue to keep an eye on it. If it gets worse, I’ll take it to a shops but the general consensus seems to be that it is no big deal.

 

Throw a bottle of AT-205 in your oil crankcase.

 

AT 205 is bullet proof. I used it on a valve cover leak on my LS430 lexus and a year later, still no leak. My SC430 with 200K is just starting to "smell;" and I will be doing it to that one also.

 

I've used AT 205 in the past and had luck with it. I'm not stirring the pot on this but I put a whole bottle in the crankcase on this round a week before the valve cover gasket job and i still got a leak. The stuff works but whatever is causing my leak has it outgunned. I'm still chasing the source...

 

If your oil leak is as minimal as you describe and you are not having to add oil I would leave it alone until it gets worse.