levi_v

Hello all, I recently had some overheating problems that would only occur when under strenuous conditions like going uphill for any length of time. Also I have noticed that while going uphill for any length of time while keeping my foot on the pedal the blower fans in the cockpit will shut off and sounds like they transfer over to defrost mode?

Since my last incident here is what I have changed out in hopes of solving my temperature issues:

Radiator
Water pump (flowkooler)
Lower rad hose (dealership one with spring)
Upper rad hose
Fan clutch
Thermostat (195deg)
Thermostat housing
Temp sensor
Radiator cap
50/50 fluid
Serpentine belt

I took it out for a drive uphill on pavement at about 60-65mph and it sounded like the valves were starting to ping after a while. My temp was around 220 when that was happening and I didn't want to push it anymore uphill for fear of overheating again. I don't seem to be loosing any coolant, except for when I overheat obviously. I am also not seeing any contamination in the radiator fluid which makes me believe the head gasket is okay. I can drive it around all day long on the road and it will stay between 200-215, but when I get to the hills is when I start to have a problem. Anyone have any ideas?

s346k

did you flush the engine and heater core when everything was out?

hellmouth19d

Sometimes a blown head gasket isn't super obvious. You might want to go to local auto parts store and rent a compression tester. It wouldn't hurt.

levi_v

Yes, I flushed everything. I guess I'll have to check the compression and see what's happening. Not sure what else to check.

cruiser54

I've had new radiator caps not clamp down tight enough on the radiator. No pressure held in the system =overheating.

Roler

To address this first issue: defrost is the default setting. IIRC, this could mean you're losing vacuum...

Roler

In addition the already mentioned things to checg, regarding your overheating:
You pretty much replaced ALL cooling system parts and still run hot on a hill. Cruiser's rad cap is def worth checking, since the pressure might be ok going around town, but not in engine stress situations like towing and climbing. Check if you're not losing coolant.
Makes me think about added heat, or poor heat transfer, like in my case occured from ATF which was old and needed replacing. It made a significant difference in temp during climbs and even the floor between the front seats became remarkably cooler after the (full ) ATF change.

levi_v

Okay, I did a compression check and I was between 144psi and 151psi on all the cylinders.

Is there any way to check to see if the radiator cap is working okay? I will have pressure on the system when it is warm (very slowly loosening the cap). I wouldn't think that the ATF would cause the system to overheat like this, but I could be wrong. I am tempted to take out the thermostat and just run it without it to see how it does.

cruiser54

Have the cap tested or just get a new one. Get a 16 lb cap even though it calls for a 13 lb cap.

Roler

Black, old ATF will contribute to the heat, and be just enough to cause that overheating. It will not cause the overheating itself, but adds up.

You can test your thermostat, watching it opening in water as you heat it up on the stove. My new Gates didn't open half as much as the OEM I purchased after that, when checked this way.

Since you replaced all parts, is will likely not be a major malfunction that you are trying to chase, but all small things add up in a system overheating under strain, that doesn't overheat when just driving around town.

Turbo X_J

Probably never warm up, thermostat only provides for a minimum temperature not a maximum.

levi_v

With a vacuum leak it would run the system somewhat leaner, could that cause an overheat problem?

cruiser54

No, as the fuel injection system would compensate for the leanness. Besides, you have to run something awfully lean to cause coolant overheating.

levi_v

Hmmm, I'm running out of ideas. I have been in almost triple digit weather here, but I would think that it should handle it. Would I possibly get any better results from running a 180deg thermostat?

Slimgoaty

Might be a dumb and obvious question, but you dont have a big old winch mounted in front of the grill do you? Or an aftermarket bumper that might be deflecting the air going threw the radiator?