help diagnosing overheating problem

[Four0Sport]

week or so back I was on my way to a trail run and noticed the engine temp was running warmer than normal. on the trails the engine temp continued to rise along with the trans temp. got home and the overflow tank was boiling over so i changed the thermostat and filled/purged the coolant system. the truck sat until yesterday, took it to gas it up for a big trail ride today and the same thing happens. when I left my house the overflow was empty, get home and the overflow is filling up to the brim and bubbling violently.

talked to a few friends with shops and knowledge yesterday, a couple mentioned a plugged radiator or bad water pump. well the water pump isnt leaking or making noise, neither is the fan clutch.

several poeple mentioned a cracked head gasket.. with compression blow by forcing the coolant back through the system. sounds possible, i just have a hard time believing that since the truck never went out of the normal range. will be doing a compression check as soon as i fully wake up.

any feedback? ideas? things for me to check? let me know, cause i am ticked lol first big trail run of the year, i have a full tank of gas, but cant go!

 

[MrShorty]

If it seems worse at slower speeds, I'd check the fan clutch. Best test I've found for the fan clutch was in a Mitchell manual. They recommended 1) pull fan clutch, 2) locate thermostatic spring on front face of clutch 3) disengage outer end from notch and rotate spring 1/4 thrun CCW 4) reinstall and test drive to see if overheating is resolved. If yes, then fan clutch is bad. If not, then something else is the problem.

 

[Four0Sport]

just got done with a compression test.. nothing too out of the ordinary, read as follows:

115 110
130 125
115 110

did hear the fan clutch come on shortly after re-start, going to pull the radiator and hose it out, lots of mud in between the fins. hopefully its something simple and stupid and not anything major.

thanks for the feedback mrshorty!

 

[Four0Sport]

pulled the drain **** on the radiator, couple squirts of thick muddy water and then coolant/water. bottom fins of the radiator were caked in mud.. took more than 10 mins with a water hose to get most of it out. ran water through the radiator, lots of brown muck coming out. also noticed some gunk in the trans cooler ports. regardless, im picking up a new radiator. gonna get a second opinion on the fan clutch when my dad comes over. i can spin the fan blade fine w/out force though the fan doesnt stay spinning. thermal spring on the front of the clutch is caked in grease/mud/water

 

[Wrench]

Sad numbers for compression. Did you do it with throttle wide open and engine at operating temp?
Sludge at the trans cooler ftgs on the rad is not a good sign. When did the trans last get a complete oil change & filter?
What color is the engine oil?

 

[Four0Sport]

those numbers are well w/in normal range according to the repair manual i have and were done with the engine at operating temp. a pan drop and filter change was done on the trans last summer, with a drain plug added to the pan and I have drained and refilled twice since the pan drop. oil has been maintained well and is not an unusual color or a high level.

replaced the radiator, hoses, and cap.. cleaned out the overflow (lots of mud inside) and filled/purged the system. let the truck run for ~45 mins, have great heat, no white smoke out the exhaust, idling temp is back to normal. got dark on me and I had some things out so once I get that cleaned up in the morning I'll take it for a test drive, wish me luck!