I have a 2004 Ranger with 4.0 V6. I've had to replace the thermostat o-ring a few times, and the housing once. It's started leaking again, so last night I bought a new o-ring and after putting it in it leaks worse. What would make it worse? I can't for the life of me figure out how to just get this thing put together and running without leaking.

 

Could it be the oring wasn't the issue and the housing has expanded/worn? I love my truck, this is the only thing that drives me crazy about it. I've got over 300k miles on it and this is the only issue Ive had with the engine

 

Welcome to the forum

Good thread to read on that here: https://www.explorerforum.com/forums...arison.472522/

Rangers and Explorers used the same 4.0l SOHC engines, so had the same issues with that housing

 

I'd love to order one of those metal housings and just do everything right. But I need to get this thing fixed quickly. I think I'll buy another outlet piece tonight and see if I can get it to seal.

 

I wonder if using some RTV around the outlet would help.

 

That would be fine to do

But long term you know whats coming from looking at the past
"I've had to replace the thermostat o-ring a few times, and the housing once. It's started leaking again......................"

One definition of insanity is "repeating the same thing over and over, and expecting different results" - Albert Einstein

If you want different results than what you’re getting, you have to try different approaches.

 

Yeah I think I will order the metal housing. But I have to get on the road tomorrow and can't get it here that quick. Not sure if the RTV around the base would do anything, don't know why the damn brand new oring still leaked. But the housing isn't leaking, it's just coming out where the cap meets the housing,

 

Once you get to it you should see why its leaking

 

I took a good look this morning. Can't see at all why, it's put together as should be

 

Well that was it. The new export cap was a tight fit, the old one slid on and off more easily. I had to tap the new one down, but it doesn't leak at all now. The leak I had developed over the course of several weeks, so I guess that part just changed shape being hot and cold or something, but it's fixed for now. I will at some point buy a whole new metal housing so next time I have issues I can fix it for good. Damn truck has 320k miles on it, so I am kind of at a point where I am not planning years ahead, although I'd be happy if it last, I don't like newer trucks the same.

 

Good work