4.0 SOHC still leaking coolant! Any ideas? | Ford Explorer Forums - Serious Explorations

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4.0 SOHC still leaking coolant! Any ideas?


Well-Known Member
August 24, 2002
Reaction score
City, State
Clayton, IN
Year, Model & Trim Level
199 Explorer Sport
I have a 2004 Ranger 4.0 in my Explorer, last weekend I replaced the entire thermostat housing and sensors. It is not leaking nearly as bad as it was, there used to be a puddle of coolant in the valley. Now the valley is dry so I don't think any coolant is leaking from the housing or sensors. However I am still leaking coolant from somewhere. I can see the passenger side rear of the block behind the oil filter is still wet with coolant. I don't see any leaks from the heater hoses. I can't see anything that could be causing this. Any ideas??

Thanks in advance.

I know how hard that is to diagnose, buried in there like that. By the time you get enough put back on to get it running, can't see in there worth anything. I had to do the R&R so many times due to having defective replacement housings. I should have borrowed a pressure tester to check with before putting the plenum etc. back on. Four times... Leaking worse than before, til I put a Dorman on it.