I just drained my radiator and put some radiator cleaner in. I was headed to the store to get some wood and my rpm's went up to 1500 to 2000 while idleing. I anticipated that the radiator may need more water so I brought a gallon with me. I opened the cap and the level was full so was the overflow tank. The top hose was hot and the bottom was not even warm. Started the truck up again and headed home, turned the heater on full blast and cool air came out. I heard some gurlging noises and then the air out of the vents got very hot like it should be. The water temp guage started to go down after the noises and the hot air coming out. I got home and checked the levels again the overfill tank had lowered, but the bottom hose was still much cooler than the top. Is my thermostat bad? There is a sticker that says the timing belt was replaced and I am not sure if the water pump was done as well. How much is a thermostat?

 

Thermostats are like $300-$400. Sounds like you had air in the system and caused the thermostat to stick....in which case you'll need a new one. Probably a valve job, too.

Okay...sorry, I'm bs'ing you. But, it does sound like air in the system. Thermo's are cheap...like $8 at NAPA. Twice that at Toyota. If you're water pump is bad you'll feel some play in the bearing and possibley hear some noise.

Do a search using some of these as keywords and you should turn up a fair amount of info. It's been covered a lot.

 

Bleed your Coolant first, after that, if its still overheating, you will need to change your therostat. the reason the top is hot, and the bottms cold is becuase the thermostat is stuck shut, therefore not flowing rright and overheating

 

Just change it, why take a chance. It is a cheep fix if that is what it is.

 

Air in the system could cause the same scenario even with a new thermostat.

Yours is probably still good if you had no problems before the flush. However, they are cheap like he said. So, if it hasn't been changed in a while and it's all nasty lookin'....and considering you just had to flush the system....it's probably not a bad idea. I would, anyway.

 

Thanks for the replies. I did not have any probs before the flush. I went and inspected the overfill tank again after the truck was sitting for a couple hours. It was completely empty. I added some more water in the overfill and went to the store, everything was fine. I think Thook was right about the air bubble, after I heard the gurgling sound everything went back to normal. Kinda weird I went ahead and bought a new thermostat anyway just in case. Cheap insurance. I'm kind of jumpy with the head gasket issues on these 3.0 motors. I do not want anything to overheat. I did a search and found a fella who bought an all aluminum radiator from Summit for $180. The scale and deposits in mine are bad, hence the reason for the flush cleaner I added that caused this problem. A cool motor is a happy motor

 

Unless you really have the money and don't mind spending it....and you like a bit of bling...the aluminum radiator is kind of overkill where you live. On the other hand, I suppose they are less prone to corrosion. So, whatever you want to do, but a standard radiator would be just fine for a good while. Just remember to use distilled water to mix if don't get the premix. And burp/bleed the system as he said, but before you go driving it. Just take the cap off and run the motor until the thermostat opens and all the bubbles come out. The coolant will start flowing.... as you'll see...and get all hot and steamy. Then, make sure there are no leaks at the radiator, heater, and bypass hoses. More air will get into the system that way.

If the radiator is real bad as you say, get the block and heater core flushed, too. Made a big difference when I had it done. My brand new coolant didn't get all rusty shortly after putting it in.

Oh yeah, another thing I've found. Pulling things like the coolant temp sensor, the sending unit, and the cold start timing switch and cleaning them up made for a happier motor.

 

I have changed hundreds of radiators and thermostats over the years and i have never heard of burping the system until i started reading this forum.. I'm not disputing it but i have never had too.. I just do whatever work need to be done, fill it with water , crank it and let heat up to temp,top it off , put the cap on and done...

 

Well, essentially that's what you're doing there. You've refilled it, the coolant circulates, any "possible" air is displaced..provided you have the cap removed, and you top off.

I have to say this is a standard procedure and pretty common knowledge, though. And it's not even particular to this forum. Hell, I'm fairly certain it's even in the service manual.

Here's instructions on a google search...
http://www.ehow.com/how_7369_burp-cars-cooling.html

 

Ok i get it, there are people who fill it and then not let it warm to temp and top off.. Ok i thought that was common knowledge to anyone that COULD change a radiator or thermostat ...my bad

 

i had an overheating problem not to long ago.. i changed the thermo and flushed the radiator and it still overheated.. turnes out the cap was faulty..

ttyl