I have a '97 F150 with 50K miles on it, It just started to leak coolant from under the truck. It seems to only leak after it's been driven and shut off. It will not leak when it's running. I know i'm not the only one who's got this problem, someone out there has to have had this problem with their truck too. I've traced the leak up from the bottom and it seems to be coming from between the firewall and the engine area, but I couldn't get that far in there. Can anyone give me a hand here? the truck runs fine, idles fine, no check engine lights or anything.

Any help would be great.. thanks,
Larry

 

Check the heater hose connections on the firewall. It'll be just above the pass side valve cover. If that's the source of the leak, you should check out your # 4 spark plug. If you have the 4.6, the plug hole may be full of coolant. If you have the 5.4, the same thing, but your coil may be short lived.

 

Most vehicles that I have owned that only leaked coolant when running or very hot turned out to be the water pump shaft seal.

 

If you do a search on this topic, you will find a library of information of the leak that MitchF150 is referring to.

 

I will check it when I have time today. I have a 5.4L and I've read every article under "engine" section back to '90 and have done a search and doesn't seem to find anything related to this. The problem only exists when It's turned off after running, it runs fine and there's no over heating either. So I'm still kinda confused on what could be leaking. I guess I"ll have to get more time to check into it.

Larry

 

With the water pump shaft seal, this is the exact symptom that occurs. No leakage until the engine is shut off and the water pump cools down. Then at some temp between hot and ambient, the seal leaks what fluid is currently in the pump chamber above the seal down the front of the motor.

Where is fluid leaking from, front of engine? Back of engine? Right? Left?

Also, I have had vehicles the got a pinhead leak in a radiator hose that resulted in a very fine stream of fluid escaping. So fine that it was not noticable until the vehicle was parked and the stream would eventually cool whatever it was hitting enough to drain to the bottom and drip. Obviously, this would only leak when hot and stop with system pressure was gone (cool).

Hope this helps..............

 

It seems to be leaking from behind the engine, between the firewall and the engine maybe and somewhere near either the pass side and the middle. It's leaking on the tranny from up top, so it's actually dripping down on the ground from right under the tranny fluid tank onto the crossbrace that goes from side to side at around the middle of the cab area. I took off the heatshield of the exhaust to follow the trail, and it seems to be on the wireloom that goes from the tranny all the way up into the engine bay. I'm just trying to figure where it is coming from around the rear of the engine. I'd like to fix this thing myself cause I like doing this grease monkey stuff, and also i'll save a bit of money too. any help would be appreciated. thanks,
Larry

 

Can't explain why it only does it when shut off, but the only coolant lines on the firewall that I know of is for the heater. You usually just have to tighten up the clamps on the hose directly above the #4 cylinder.

I did a search for "heater hose" and came up with about 66 posts. All it really boils down to is tightening or replacing the clamp on the hose(s).

Good Luck!!

 

I'll definately have to go through and recheck the leak, and most definately check that heater hose you're talking about though. Thanks,
Larry

 

intake manifold gasket on passenger side - replace both of them as they may look as if they can be reused but don't - don't mix them up either as they should be specific (lt or rt)

p.s have fun and dont let any little rocks or any thing else get into the intake ports (heads)

o yeah its always a good idea to pressure test the system to make sure but i am just going by what u describe, just double check all the heater hoses and the water pump feed tube wich runs under the intake (steel tube) and bolts to the pass side head (rear) and then rubber from there to heater core. You may also want ford to fix it aswell depending on your ability and tools

 

The reason that it only does it on shut off is likely because the internal engine temperature is much hotter than the coolant temperature (the fan cools the coolant). When the engine is at operating temperature and you shut it off, the entire system temperature rises which means an increase in pressure which means you may have a high (higher than operating pressure) pressure leak. It will only leak until either the system temperature drops or the leak bleeds off enough of the excess pressure.......

Hope this helps... back of the engine sounds like your heater hose clamp.... I would check that first.

 

try looking under the intake manifold with a flashlight at the engine block, under the intake manifold the block is like a big valley, if you have coolant in that valley it could be the intake manifold gaskets, or the heater tube, also check at the back of the engine, on the passenger side cylinder heaad, there is a heater hose there, that could be leaking, good luck.

 

I've fixed this problem, but I just want to post here the solution I found.

Somehow the idiots at ford designed a drainplug for coolant right above the passengerside plugs (the back two). The engine is slanted a little towards the rear also, as the coolant leaked from this plastic drainplug, it got into the third coilpack and as that hole filled, it overflowed to the coilpack right behind it. I had to replace all the plugs because of those two. The plugs were rusted to heck too, i'm glad I cought this proablem earlier because the plug #4 could have rusted so that I wouldn't be able to get it out.

anyways, I hope this helps out somebody.

Larry

 

yeah I'm in the same boat right now but I diagnosed it to the line going underneath the intake manifold if you pull your alternator you'll be able to see the lines pretty easily but can't see it without it it will leave right from their travels to the valley cut it down and leaks right out the side of the engine block between the block and bell housing sometimes right down into the transmission where yours is I'll bet that's what's wrong with yours.

 

You quoted a 20 year old post, and the issue was fixed 18 years ago.