Howdy all! I have a 98 expy 5.4 and I have been losing water from the coolant resevoir. I have noticed none on the ground and the dipstick looks good other than needing to change my oil. Anyone have any clue? Going to have a hydrocarbon test done on the coolant on Tuesday to check. Could this be from either wtr pump, hoses, thermostat or a combination of it all? Motor is dry on the outside for sure. Thanks to all!

 

That sound like a heater core problem.Do you get a sweet smell coming out of you vents when the heat is on?You'll be able to taste it if it is real bad.Also lift you carpet back uder the front of your dash if you can and see if it is wet.If so you need a heater core.I've had this problem before and it wasn't fun.I hope this is not your problem but that would be better than internal engine problems.

Bob

 

No I have not noticed any htr core problems. No wet floors no antifreeze smell w/ the htr on thru any of the vents. The truck is not running hot either! That is what confuses me more than anything. If the head gasket was blown I would think that I would be having a boat load of problems! Correct me if I am wrong!

 

Come to think of it a friend of mine has a 99 F150 and he actually had to have the cylinder head replaced when it was fairly new because of the coolant leaking through the head and he didn't notice it because there weren't any symptoms besides coolant disappearing.Thank God his warranty covered it then.Do you have the 5.4?I have heard this was a problem in quite a few of those engines in the 98-99's.

Bob

 

Yes i have the 5.4. I think it is an early 98 though. I have a lot of 97 type stuff. Hopefully it will all work out! Thanks for the info!