I have a 92 F250 with a 5.0 and I've noticed the coolant gets low, needing refilled about every month. This never happens when it's hot outside. I've been crawling all around and can't figure out where it's coming from. I thought I seen some below the radiator but it think it's was from some that I've spilled. Now, my reservoir hose, it needs a clamp where it connects to the tank. If I pour any in it, it'll leak out. Is it possible that the radiator pushes it into the reservoir and could suck it back in but obviously can't since it leaks? Any other suggestions???

 

That is but it would do it when its hot out. Got me stumped. Bump to the top.

See any stain's from the cap down the driver side on the inside edge ?

 

I had a coolant leak in my 5.0 that drove me nuts for years. I finally figured out it was leaking from the weep hole in the water pump. Another Napa water pump story.

I've also seen one leak from the rubber cap supplied with replacement radiators to cap off a coolant port below the port going to the coolant bottle. The caps supplied with the replacement radiators develop a small crack that leaks coolant slowly.

There was no trace of coolant coming from my water pump weep hole until I did an engine change. The donor motor had been filled with tap water and the rust colored the coolant; it left a trace when it escaped the pump. Once I changed the pump, no more problem.

 

I haven't noticed any stains. But that hole on the water pump deal could be it. I know it's a cheap one from advance auto parts. I was thinking that maybe the pump gasket is leaking and it flexes different in the cold?

 

I was ruling out the main cap..

 

You may be right! I know they're cheap so I might go pick one up. I do know there are a few stains on the side of the radiator but they've been there forever and I don't think they've gotten worse. The stains are there from me overfilling

 

Every now and again mine would puke from the cap. More so just after I checked it. Took a while for me to catch on to what was going on (not seating right anymore). Think the new one was 7 bucks and I have saved it back in coolant by now.

I dont think thats it if there is no new staining but hell, as you said, they are cheap enough. I'd see if that weap hole is dripping while its running if your seeing significant loss for sure (also I know you'll check- just saying). GL on the issue!

Just popped into my head - EDIT:
I also had a leak at the top of the oil cooler tube that ran down the back and was hard to see till I got up close and personal with the drop light. That didn't drip down to the ground to be seen also.

 

Just popped into my head - EDIT:
I also had a leak at the top of the oil cooler tube that ran down the back and was hard to see till I got up close and personal with the drop light. That didn't drip down to the ground to be seen also.[/quote]


Is that the transmission oil cooler you're speaking of?

 

No, engine oil. IDK if your truck has one or not.

 

I don't think mine does but I'll check anyway

 

Its a sandwich type. Between the block and the oil filter Two 1/2 ~ 5/8ths coolant lines run off it to a odd looking T into the 2 inch main line... ugly mess. Cant miss it.

 

When it is cold the rubber hoses are not as soft and do not conform to where they fit, can contract and leak or weep in such small amounts you may not see the leak. If the hoses are over a few years old, replace them. At least tighten all your clamps. Been there, had the problem.