Rob Bowie

88' yota 4banger, overheating issue. Replaced cap/them stat/flushed- parked on slight incline to burp but still seems to be overheating. Only thing Left is the pump but no leaks or squeaks, and with cap off and revved up the fluid moves. I'm lost please turn on the light I need her up and running to salvage the rest of my hunting season!!

DemonRunner

Radiator plugged , head gasket going bad, whats the gauge reading?Fan have good flow

Rob Bowie

The radiator is old but I removed it and cleaned it inside and out everything's clear and operable. fan good, shroud etc., gauge climbs up to red after warm up

wyoming9

iTrader: (1)

If the radiator is blocked unless it was taken to the radiator shop and taken apart .Which with labor costs most don`t want to touch small automotive radiators

No amount of flushing is going to remove the blockages.

Infrared Heat gun is great for seeing blocked radiators.

You don`t mention any coolant loss

Your not having temperature overshoot caused by poor aftermarket thermostats??

Rob Bowie

No coolant loss, three different stats ending with a fail safe thermostat. Could it be and air pocket?

mct75

I have always have had luck squeezing the upper rad hose with my hand. The squeeze is not what does it, but the release. When I let go it will suck the bubble past whatever obstacle and it siphons coolant up into wherever it needs to go. I do this with the rad cap off. Pump the crap out of that upper hose and eventually it gurgles and the coolant level drops in the rad below the core, so a bunch of air got displaced with coolant.

wyoming9

iTrader: (1)

All my 22R series engines have a tee in the heater hose.

I fill the system with the cap off it pushes all the air out.

Has been working for years no more air pockets.

RAD4Runner

Fan Clutch may LOOK like it's working but it may not engage as much when needed.
Liquid Couping/Fan Clutch senses temp or air blowing from radiator to fan clutch

When air blowing from radiator to fan clutch is cold, fan clutch has little engagement.
When engine has warmed up and air blowing from radiator to fan clutch is hot, fan clutch should engage more; Meaning fan speed would follow speed of pulley more closely.

Feel resistance to turning by hand with engine cold. Compare with resistance to turning by hand when engine is hot. Do second test after parking for a few minutes to make sure there is no more cold air from highway speed blowing from radiator to fan clutch.

You can also try this:

Start cold engine. After a few seconds (still cold) Turn IG off. Count number of seconds before fan stops turning. Call this Time 1

After stopping from a drive with engine hot, park for a few minutes so you know only fan air is cooling radiator and not cold highway air. Turn Off ignition. Count number of seconds before fan stops turning. Call this Time 2

Time 2 should be shorter than Time 1 because former follows pulley speed closer than latter, because of more engagement when fan clutch senses hotter air.

Odin

You put it right after the heater control valve up on the firewall right?

wyoming9

iTrader: (1)

I put it to the left of the heater control valve.

toward that brake thingy !!

Rob Bowie

I cut in an inline tee and got all the air out now overheats when at idle but cools down when revved up, radiator blockage? Even though I removed it and flushed it out vigorously getting out some brown crap. Thanks for the help guys!