Working with a '95 F150 4x4 5.0L auto, 89,000 miles. I am seeing coolant leak off the oil pan. I don't think its the freeze plugs because I reached down and they all feel dry and the ones I can see don't look rusted out. The seam between the head and block appears dry also. It usually does it after the truck is run and then parked over night. While cold, I hooked a coolant pressure tester up to it and pressurized the system to 30 PSI. It held the pressure and I did not see or hear anything leaking. I have checked all around the front of the engine and on top and can not figure this out. I did a search and some people say something in front can leak, run down the oil pan rail, and then drip. The water pump is not leaking out of the hole. I don't see anything leaking up front although that area is most suspect. One time I saw coolant coming off the driver's side oil pan rail but today it was coming off the passenger's side. Radiator is bone dry and overflow tank and hose are not leaking. I do have a mild coolant smell after driving the truck and I do have to add coolant fairly frequently. Maybe try running the truck for a while and then pressurize the system and check again?? I don't want to add coolant system stop leak. Would like to find and correct what ever is leaking. Any advice greatly appreciated, thanks.

 

On my Suburban with a 350, I had a similar leak. It was the lower intake manifold gasket. Not sure if the Fords have a similar design or not.

 

My '88 4x4 with the 5.0 has had a leak at the intake manifold on the driver's side at the back. One time I left a little puddle but couldn't figure out where it was coming from. I later saw water/coolant staining where intake manifold meets the driver's cylinder head on the back of the engine (I was looking from underneath the truck). I used some alumiseal to fix it temporarily, I plan on changing the intake manifold gaskets soon. While I am in there I will change the valve cover gaskets and thermostat too.

 

There is a second weep hole on the bottom front side of the water pump. If coolant leaks from there it will drip down and coat everything below it.

This leak can be tough to find but if you look at the lower weep hole and find that it is wet, you just located the leak.


Lou Braun

 

Thanks guys. I looked at that weep hole on the bottom of the water pump and didn't see anything. I'll keep looking. Thanks again for all the tips so far.

 

have your system pressure tested if you want the answer to where it is leaking.

 

I bought a coolant pressure tester, hooked it up, and pressurized the system to 30 PSI. It held the pressure and I did not see or hear anything leaking. This was with the engine cold. When I get some time I'm going to warm it up and then pressurized it and see what happens.

 

heater core?

 

I don't smell anything inside the truck. I get a mild coolant smell from under the hood after driving. No smell at all inside the truck.

 

the plastic on the side of the radiator is the secret place i always find a hard to find leak.

it opens and closes wih the fluctuating temps.

also hard to find is a very small leak in the heater hoses.

 

Do this and check back: When you turn the car on for a while, or go somewhere a little bit up the road turn the heater on and do a smell test. You say there is not a smell of any coolant in the cab but that may be because your heater is not engaged. Engage your heater and let it run for a bit while your truck is on. If you smell that radiator smell, there is a possible leak in your heater core.

Motorhead26

 

Next time I take it out I'll try turning on the heater.

 

yeah man, check it out and turn that heater on. It is not to hard of a fix because it is right behind your glove box, but it is a b*tch trying to find leaks. I have coolant and Transmission leaks on my truck. Mostly from poor maintenance and old worn hoses that need replacing. Hope you find it.

Motorhead26

 

I was in Autozone the other day and they have dye you can toss in your coolant system. Throw it in let it get good and warmed up and then pull 'er in the garage, shut the door and get out the kids black-light

They also have dye for the oil and AC system.

 

One more question: Do you hear any water driping noises? Do yourself a favor and inspect all your hoses. Also check around the seal on your water pump, as well as the seal around your intake manifold. High engine tempertures cause engine gaskets to fail and this may become a problem for those tune ups that you may miss every now and again. Be sure to flush your radiator regulalry and replace your thermostat and refill system.

Motorhead26