2000taco

ok so my 3.0 is over heating on me. does it on the freeway and it did it going up the mountain today. the thermostat is new. i can smell antifreeze burning off right before my gauge skyrockets to high. my cap is bad but what has me confused is my lower hose is always cold.. with in 5 min of running my truck is nice and toasty in the cab in 40 degree weather. what could it be? water pump im assuming? i dont wanna do the whole trial and error thing and just guess lol.
thanks for the help.

TNRabbit

So it only overheats at speed or up a grade? Your radiator is clogged. Replace it.

2000taco

Don't think its the water pump? And yes it over heats at high rpms basically. Should I try to flush it first or just put a new one in?

cracker_1

X2 on the radiator. Open the cap and watch the fluid, see if it moves when the engine starts to warm up. You can try to back flush it, wouldn't hurt...

2000taco

I can't tell if its moving. How do I do a back flush?

Cam72SS

2000taco, does your temp spike and then go back to normal for a bit, then spike again? or does it only go up when you speed up?

2000taco

Well the radiator is fine water flows threw it great. What else could it be

2000taco

It spikes than when I turn on the heater it goes down. And my thermostat is opening at 195 but I got it from napa and I'm not seeing a "jiggle valve" on mine?

What about the cap its self? mine does have cracks in the rubber seal so it could be sucking in air and if my thermostat doesnt have a jiggle valve it could have air pockets in the system?

What if i was to drill a little hole in the thermostat to act as a jiggle valve? just throwin out some thoughts...

TNRabbit

I doubt flushing is going to work. You can get an all metal radiator like mine from CSF, practically just like OEM, for around $200--it requires a tiny amount of pounding to shape the bottom edge to fit in between the rails, but it's 1/3 the price of OEM:

https://www.yotatech.com/forums/f116...d-pics-193478/





Be sure you get the THREE ROW model.

2000taco

The water ran threw the radiator great I hooked a hose to the top hose and it ran out the bottom hose just as fast as it went in.

TNRabbit

I'm telling you, it's not hitting all the cooling fins. It's not about how fast it goes in/out, it's about having fins clogged up. Trust me on this; there nothing else that will cause your symptoms....

2000taco

well that makes sense. than i think ill get a radiator from a buddy of mine just to make sure its that before i buy one. dont think it could be just the cap? and i have heard of ppl gettin there radiators dipped in acid and rinsed back out. think i should try that?

TNRabbit

It depends on how much the acid bath costs.

If the cap were bad, you would have excess coolant going into the overflow.

calvinh

My Runner was doing the same thing. I had the radiator flushed 3 times and it still did it. New radiator and the problem was gone.

2000taco

well the cap is bad i can squeeze my upper hose and hear a hissing sound from my cap. im going to try a new cap and see if that works first. any thoughts that it will? if not i guess ill be gettin a new radiator.

fork

my 87 had mud compacted in the fins. i soaked it in water overnight and applied pressurized water from the inside->out first, then out->in, put it back on and it's been flawless ever since.

also replace the cap if it's obviously bad. it'll cost you the price of a beer

Da_Beast74

Again, a subcriber. I have a BAD over heating problem. The problem is mine is a whole lot worse. My engine will over heat no matter what i do. Idling, running low rpms in the city, 5th gear on a cold day doing 65 on the freeway. I have flushed the radiator, switched the coolant, and changed the oil.

The fins are not looking too good, but this has never happened to me before. It was fine, temp was perfect until one day it started over heating while on the freeway, and then eventually it started over heating no matter what within a week or two.

Any thoughts? This is killing me. I am about to rebuild the motor as well. I spun a main bearing pretty bad and basically drove it knocking until it basically was too much. I dont think this bad bearing would have caused this over heating problem though. HELP!

TNRabbit

@ Da_ Beast74:

Which engine? If you spun a bearing, that's a sure sign you've had water in the oil. The bearings are the first to get the short end of the stick when water gets in the oil.

Is the coolant level dropping without signs of a leak?
Are you getting any white, steamy smoke at start up?
Could be one of two things; a head gasket leak OR the idle control valve o-ring is bad & allowing coolant to leak into the throttle body.

Da_Beast74

Um.. 22r engine, carburated, stock everything im sure. uhh, if i remember correctly, the coolant level was usually fine. It was the oil i was loosing about a quart a week about with out signs of a leak. No black smoke out of the exhaust though. white or grey smoke recently when cold.