Ive been chasing what appears to be an overheating issue for a while now but haven’t nailed it down yet. I have a ‘92 5.0 and for several years now have had intermittent heater issues(goes cold) and the temperature gauge seems to move around a lot...but mostly sits on the high side of the range. Sometimes I’ll get a whif of antifreeze when i turn the engine off...but haven’t had any steam or leaks. Had a local shop dye test the system and it came back normal. I can hear the coolant flowing through the heater core when i start it up...not sure if that’s normal.

What I’ve tried:
Thermostat replacement
Burped the system
New heater core

Sometimes the temp will read pretty steady with just a little movement on the gauge...other times it’ll start to warm up then start falling off cold again...then come up and hover in the normal range...then shoot way up to the HOT side and then come back down again. Ive also been adding about half a gallon of 50/50 to the radiator about once a month. The truck isn’t a daily driver...more just a bad weather and weekend truck.

Any suggestions are appreciated...getting pretty frustrated with it now.

thanks!

 

still running the fan shroud? perhaps the fan clutch is failing and needs replaced. is the radiator cap new? the stock temp gauges suck in our rigs so you might consider going to a manual or electric aftermarket gauge.

Perhaps you have a headgasket leak. do you notice any coolant smell at the tailpipe? the fluid is going somewhere if your having to add that much.

also what temp tStat did you install? should have been a 195*. and hopefully you installed in correctly.

 

Thanks for the advice! I installed the OEM 195 thermostat...the one that wqs in it already was actually in backwards so ive fixed that problem. Not seeing any leaks anywhere and the exhaust is perfect...no smoke or steam of any kind. Had a shop block test everything and it came back showing no leaks with the dye test.

Havent tried the radiator cap yet. Would the fan clutch have any symptoms or make any noise? Still have the original fan shrouding as well; as far as i can tell pretty much everything is still original.

 

the fan noise tends to be loud, almost like the fan is engaged all the time. or perhaps in your case its not engaging enough causing this issue.

I would consider and aftermarket gauge then.

 

does it have a overflow bottle and are you using it to keep the system full.

 

check around the front and rear of the lower intake to the cylinder heads. they can leak there and not be easily noticed unless you look sometimes.