[firebiz16]

Ive had overheat problems as some of you have probably read from a previous thread.

Today I removed the thermostat and my 95 3.0 ran at almost normal temp, just a little below. This was at idle and driving for about 30 minutes at diffent speeds. Never attempted to overheat.

Let it cool down and put the T-Stat back in, refilled with coolant and the dang thing starts overheating when I drive it less than three minutes. It will not overheat while just sitting and idling.

I replaced the STANT T-stat with the TOYOTA T-stat this morning and it made no difference.

ANY IDEAS???

It is running rough and the timing seems to be off, but I'm pretty sure this is due to the knock sensor code I'm getting.

Thanks
Chris

[DC runner]

Your truck is running hot and probably has some bad hot spots.


If your truck is running "normal" with out a thermostat, then it is running hot. Usually, with thermostat in, an effective cooling system will keep the engine at temp once it opens.

Without a thermostat, the engine struggles ( or should) to get up to heat.


That your truck heats up quickly without a thermostat leads me to believe you have an issue in your cooling system that isn't thermostat related.

[firebiz16]

The only thing left is to take it to have the block blown out I guess, to see if there is a blockage, the entire cooling system as been replace.

T-Stat, Radiator, Cap, water pump, belts, hoses, valve covers and flushed three times. With the T-Stat out, you see water rushing through the RAD. Not much movement when t-stat is in, actually spurts out when it gets warm.

If it was a blown HG, wouldn't it overheat to some extent even with the T-Stat out?

[DC runner]

That is odd. You could have pockets of over heating already without the Tstat out.

You are getting a knock sensor error? Is there any knocking?

[firebiz16]

I dont hear any knocking to speak of, It is skipping though. From what I've read a bad knock sensor or knock sensor wire will cause the timing to be off.

[firebiz16]

Just took the thermostat out again, put everything back together, drove about 15 miles and it runs like it should normally with a T-stat IN. This makes no sense. It reaches normal operating temp and I have good heat in the cab.

Maybe a severe blockage down in the block, doesn't seem to be hurting anything though.

What the heck. Any more suggestions....

[DC runner]

Well. A severe blockage IN the block will damage your block if it is creating an uneven hot spot.

If you don't have a block.. and whatever gremlin devil has left your truck. YEA!

[mikedks]

Wave the white flag and bring it in to a pro.

[Bad_Vision]

my local radiator shop offers a boric acid flush you should check out local shops to see if that may be something they offer.

in the mean time take your radiator out get some duct tape and garden hose tape one inlet with the hose real tight and crank up the water see if anything comes out the radiator.

[the_dingman]

I would suspect a bad water pump, radiator or fan clutch (is the 3VZE a belt-driven fan engine?)

There may not be a blockage, but something else is likely causing inefficient cooling. The intermittent issue may be caused by differences in local temperature. (I ran my 86' through a winter with no coolant, and it was cold enough outside that I didn't damage the engine... But I wouldn't do that again).

Fan clutches tend to do strange things when they go, where that will intermittently engage and disengage causing odd overheating and overcooling issues.

[4runner15]

I just did my head gasket and started up the engine. Runs good but havin the same exact issues as you. The top hose gets hot but the lower hose is cold. The thermostat is obviously not opening. Whats stranger for me is that it only gets hotter on the temP guage if i put the car in gear. I changed the heater adjuster, does this have to do with it?

[hoe_nah]

Are you guys burping the system? Did u try and put the thermostat in boiling water to see if it even opens?

[Hyde802]

^ This.

Could be a trapped air bubble in the system.

(is the 3VZE a belt-driven fan engine?)

Yes it is. But the timing belt drives the water pump.

[Quatre Coureur]

Had the same problem with my 85 p/u. Had my rad rodded out and that solved it. Did the whole runaround with the t-stat. If it has high miles yank it n have it recored or rodded out. Rodding pretty cheap (i paid $35). When refilling ur rad park it on a slope facing uphill and make sure ur get all the air bubbles out. Good luck.

[JakeInGrayTacoma]

Originally Posted by 4runner15

I just did my head gasket and started up the engine. Runs good but havin the same exact issues as you. The top hose gets hot but the lower hose is cold. The thermostat is obviously not opening. Whats stranger for me is that it only gets hotter on the temP guage if i put the car in gear. I changed the heater adjuster, does this have to do with it?

I've had these problems too! Had a head gasket job, new radiator, t'stat, opens; and it still runs HOT! I'm so frustrated. What can I do next? Is there a blockage? I haven't driven it much cuz I don't want to overheat and do more damage, I can't pay anymore. When I had the problems before the HG job it never ran hot!
Help!