John747

Hi all!

I am brand new to forum and I have bought a F-150 in great condition. But lately, it is leaking coolant from the back of the engine. I filled the coolant tank last night and it seems to be gravity draining from this area. It is not leaking from the water pump at all (bone dry!). The engine temp always seems to read right at the "N" in NORMAL on the engine gauge. Except if the a/c is on and then it goes as high as the "O". When the coolant tank empty's, the leak stops. Oh, I suspect the engine has around 200K plus and probably never rebuilt. Thanks for any thoughts you may have.

JJ

BareBonesXL

That implies that the leak is high on the engine. I don't know Ford engines in detail but many engines have core plugs (aka, incorrectly, "freeze" plugs) in the heads. Could also be the head gasket. Check the back(s) of the head(s). Use a mirror.

And tell people what engine you're working with.

John747

OK, thanks! It is a 1990 F-150 XLT Lariat 302 V8 Auto. I'll check with mirror as you suggested.

JJ

John747

As a follow-up, the problem turned out to be my heater core. I isolated it by cutting both inlet and outlet hoses and installed a Dorman 5/8" 90 degree elbow with two hose clamps. I found a new heater core for $27.00 at O'Reily's Auto Parts. The coolant leak stopped almost immediately. Thanks to BareBonesXL!