Mysterious coolant leak!!!...can't pinpoint...please help, pics available

[taf789]

So I recently purchased a 1999 Ford explorer sport, its the OHV model 4.0. After driving regularly for a month or so i started smelling coolant while driving one day. I went home and parked it, got under the car and found that my radiator had a half inch slit in the bottom end. So i replaced the radiator with a brand new one and drove it for another few weeks, didn't see any leaks or smells, the reservoir seemed to be holding coolant fine. Until last night driving home from work, i smelled coolant again. So i parked it and let it sit overnight to check it this morning.

I first looked in the reservoir to see how much coolant i lost and its nearly empty!! I let the engine warm up and get nice and hot before looking. The radiator is clean, along with all the hoses and therm. housing, reservoir has no cracks. After looking further i found the area where the coolant is leaking but can't pinpoint it. If your under the car, directly under the oil filter area, its soaked with coolant. Seems to only leak under pressure when the car is running. I'm not the biggest gearhead so I figured i'd get some opinions from the forum. Thank you very much!!

 

[taf789]

I'm having trouble attaching the pics. But right where the oil filter is, it seems like the leak is coming from above that. The transmission cooling lines pass right by it, not sure if this has something to do with it. Thanks.

 

[Jstcruz]

Maybe the connections at the heater core is leaking? Also, check for cracks in the tanks on the rad very carefully. I had a leak I couldnt find untill i noticed a coolant puddle on my rad support. The tank had cracked and was spraying the coolant on my rad support and just running down. It wasnt even leaking on the ground, took me forever to realize where it was coming from.

 

[Maniak]

There is a heater control bypass valve over there. Follow the heater hoses from the engine to the firewall. That does go bad over time.

Other than that, the only other not too bad of a thing would be a leaking freeze plug.

If its not one of those two all I can think of is something really bad like head or intake crack/leak.

~Mark

 

[shadowless127]

There is a heater control bypass valve over there. Follow the heater hoses from the engine to the firewall. That does go bad over time.

Other than that, the only other not too bad of a thing would be a leaking freeze plug.

If its not one of those two all I can think of is something really bad like head or intake crack/leak.

~Mark

Bad heater core could be added to that list.

 

[RomeovilleIL]

Rent a pressure tester from autozone or advanced. Looks like a small pump connected by a hose to a radiator cap. Once you pressurize the system you should be able to see the leak and work from there.