toyota over heating problem

[91yotaprerunner]

i am having problems with my toyota overheating real bad. I have been trying every thing that i think could be the problem. my friend suggested that i run a lower temp thermostat, so i put a 180 t-stat in there. didnt help. the radiator is only a month old being i destroyed my other new one at ROR. the radiator got messed up due to the way the fan was mounted with nylon bolts through the radiator, learned my lesson on that one. So now i am running an aluminum fanshroud with the fan mounted to that. still not helping. driving my truck at 75mph in 5th gear puts my truck to almost the redline on the temp gauge. i dont think the electric fan is the problem because i have run that same fan for about 7 months, and i used to have no problem doing 90mph in 3rd gear pinned through the silt bed and my truck would never go higher than abuot a 1/4 of the temp gauge. i pulled the thermostat out which was also only a month old, and it still runs the same. do any of u have any suggestions or similar experiences. its driving me crazy having to drive 35 miles to work everyday with the heater on full blast in the summer time. oh and my water pump appears to be working also. any help or advice would be greatly appreciated.
matthew

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[BlueCoyote]

Make sure your thermostat is installed correctly, and do run one. . And make sure the electric fan is pulling not pushing - seen lots of cases were they are hooked up backwards. Any water in the oil?
There was a thread on PBB about this - something to do with a 2 stage thermostat on some RE motors. Symptoms were running hot, but let it warm up, shut it down for 10 minutes and restart and the truck would not overheat. Will look for it to ya,

[91yotaprerunner]

the thermostat was installed correctly, but i had one that had a safety feature so when it goes bad it locks itself open, well after a month of using it, it was already locked open. the fan is pulling and not pushing, i did the dollar bill test to check, lol.

[fooddude]

Doulblecheck your water pump again. Why not just remove the waterpump and check if it spins properly, easily and smoothly. It aint that hard to reinstall anyways.

[farmboy]

Are you still running the stock gauge? I have seen those get way out of wack on serveral trucks. On my old 81, it worked fine for several years then one day it started reading way hot. Went through the entire cooling system, still nothing. Then I put a mechanical gauge on it just to see, and it was fine the whole time. The sending unit just crapped out.

Also, a V6 radiator should fit in there with a few small modifications.

[BigAaron]

Is it using coolant or idling funny? If so you may have a blown head gasket, and that will overheat your engine real quick. Overheating at idle or low speed could be your fan, but not at 75mph, that would probably be a cooling system problem like a leak, bad waterpump, coolant restriction, blown head gasket, etc... See if you have any coolant in the oil, pressure test the system, and check for emissions in the coolant. Is it pushing coolant past the cap into the overflow bottle? Change the cap and thermostat? Take the water pump belt off and make sure it is spinning freely.

Start there and see what you find. BTW, next time you see that guage hit the red, you should already be pulled over with the engine off calling a tow truck. Overheating a Toyota engine will warp the head and blow the headgasket.

[ACID_RAIN28]

Same motor, same problem, same city, etc. I had a blown head gasket, with the same simptoms, once it hit the red once it was done for and became an exponitial problem from that point on till it ran no more. Tried everything you did and that was the end result.

[91yotaprerunner]

ya its weird but im suspecting that it is the gauge, today it was running really hot, so i stopped to check things out, found out the wire feeding power to my fan was fried, but i had an idea to feel the radiator cap, cause if it was as hot as the gauge was showing, it should have burnt really bad, i was able to hold my hand on the cap as if the truck was cool. it was warm, but not hot at all. i always get stupid problems with my truck, charging system did the same thing.

[btshannon]

If the radiator feels cool to the the touch, but the temp gauge is still too hot, you may have a problem getting the hot water out of the engine and through the radiator to cool it off. I have seen aftermarket water pumps with an incorrect impeller blade count cause problems like this. I have also seen badly corroded impellers and even detatched impellers. I think that you should make sure that your system is circulating coolant properly.

How is your heater working? Does it feel as hot as the engine is?