my rig is a 1988 4x4 5 speed 22re with a/c. I have replaced the: water pump, fan clutch, thermostat and all hoses. as well as flush out the radiator, my 4 runner still runs at the top of the hot cold gauge. I am considering buying a new radiator, just not sure if I can get a bigger 1 and who you guys think is the best place to buy from.

 

Flushed the radiator with a hose or took it to a radiator shop? Yours is probably plugged, take it to a reputable radiator shop.

 

I bot the prestone radiator flush and followed the directions, somthing like drive the car for 10 hours then drain and fill a couple of times. the shop wants 110.00 to boil it out and I can buy new for 200.00, I would hate for the professional flush not to work then have to buy new anyways

 

are you using the heater????????????????????

 

yeah, I am using the heater. I think thats whats keeping it outta the red zone

 

Use a laser thermostat to make sure you're actually overheating, and it's not a faulty sensor, before you spend any more money.

 

the first thing I replaced was the sending unit. I forgot to list that. What is a laser thermostat and where do I get 1?

 

by laser, he meant infrared, point-and-shoot

 

does the a/c compressor run when the heater is off?
also, when do you notice it overheating most often: idling, stop and go traffic, freeway?

 

We use this model at work;



They are actually called "non-contact thermometers". We use them to measure catalytic converter temperatures, thermostat housings, and exhaust manifold temps. Great for diagnosing misfires (which exhaust runner is cold?) or a failing converter (inlet hotter than outlet).

In your case, you just point it at your t-stat housing and get a reading. Your expecting 90-95° C

Where ever you buy your tools should be able to get you one. At my shop, a ½ dozen coffee's get's you 10 mins with 6 mechanics. One of them usually has the tool you need to borrow

 

Did you check to see if your stat. is working properly, sometimes they dont work even new. Try running without the stat. and to test it, throw er on the stove in a pot of water and see at which temp it opens/closes.

 

One problem I've come across with running without a t-stat is that doing so can also cause an engine to overheat, particularly at prolonged high engine rpm conditions like on the freeway, since the coolant does not spend enough time in the radiator.
And if the t-stat is one of the 'fail-open' models, you have to pay close attention to it when you do the boiling water test because you can quite quickly push the t-stat into fail mode.

 

it only gets hot at freeway speeds. never while offroading, or around town in traffic.

 

Does it cool off when you slow down? Is it a fail safe t stat? Mine failed and the same thing happened, cool around town, hot on the interstate.

 

is the shroud in good shape? im leaning towards a radiator u can never get all the mineral deposits and crap out of the cares with that flush

 

it does cool down when you slow down. I dont think its a fail safe t-stat. its just 1 I got at autozone cause it was running hot, obviously didnt cure the prob.
and the shroud is in great shape

 

http://www.4crawler.com/4x4/CheapTri...tml#Thermostat

 

have you replaced the radiator cap?

a bad cap can cause overheat on the highway, but run fine at idle, not holding the necessary pressure.

every time i buy a different vehicle, it's one of the first things i replace. it's cheap insurance.

 

what is the temp rating on the thermostat?

 

yes I did replace the cap, and the t-stat is a 180*. I had the local shop do a flush. they said it was 40% plugged. I will test drive it today and let you guys know how it works.