Overheating. CONSTANTLY!

Hey there. I just recently bought an 89 b2200 carbd. First few times i drove it i noticed it was smoking like a mofo from under the hood once the engine heated up. finally figured out that it was the bypass hose from the intake to the block. after that was fixed the next problem came. so i replaced both upper and lower rad hoses. again (keep in mind that this is all within a week) i noticed that the waterpump looked like it was wet on the outside so i said to hell with it and spent $240 on a timing kit. new waterpump tensioner belt the whole 9 yards. Finally it stopped smoking no more leaks all seemed fine. for 2 days until it got about 10 minutes of driving on it and the temp guage rises about 3/4 of the way up and stays there. fan works. relay is fine. im boggled for ideas on why its doing this. faulty guage? rad? i dont have a clue.

If you haven't yet replaced the thermostat and cap, I'd do that first. After that, would look like a radiator (as long as you haven't overheated yours yet a blew out a head gasket).

Many of us have installed replacement radiators as these trucks age and deposits lessen their capacity to shed heat. Quite a few of us have installed 2-row radiators as well, even on our manual shift trucks.

That's what I have, and I don't overheat in Arizona summers, Cab Plus, AC on full time, going up mountains.

Mine ran like that for awhile did a new therma stat and left the cap off and let it run and got a air bubble out of it. It now runs just under half all the time.

Good point - when filling the radiator, must bleed out all the air. You can jack up the front of the truck and run the engine to top it off and bleed out the air, or just check it after driving (when it cools down) several times in the first week after filling, and top off.

Also: make sure your fan clutch is operating correctly. And that the fan belt is correct tension.

And do you have an intact fan shroud on your engine?

i forgot i replaced that aswell the thermostat that is. and it does work. its been about 4 or so days since the last bit of maintenance on it and everyday i check the rad level and it has been a bit low but nothing to worry about either way i top it up. i do have a fan shroud and the fan clutch does infact work. The belt seems to be at the proper tension and the only thing i cant understand is why it keeps happening and where that little loss of fluid has gone. there is absolutly no leaks and there is no coolant in the oil. this is worrying me simply because the last few days its happened while its -15 to -20 degrees celcius out still temp. then who knows how cold the air hitting the rad is. so if its going hot now what happens by summer time when the road temp is 50 degrees.

Still think you have a air bubble in the system some where

is it the original radiator? also is it original heater core?

If the level of coolant continues to drop, that's a big deal.

There are only three choices:
1. External leak (hose, water pump, heater core under dash)
2. Internal leak (crack or bad head gasket) into combustion chamber or into oil
3. Overflow through the cap/overflow

So I'd track down that first. If you're in Ontario California you might be able to bypass the heater core if that's leaking. But not if it's Ontario Canada.

Do you have your cat's hooked up still? It might be smokin but the silicate's are building up on the cat's. You could get a block checker from autozone and use that, I forget the technical name of it but it's used to check for the presence of combustion gases. That could help rule out or confirm a hg. Is it bubbling into the over flow when running and t-stat open? Don't always trust the gauge for a good reading, you could use a non-contact thermometer.

As Cusser said it's very important to find that leak. Overheating these trucks WILL ruin your head - guaranteed.

I recommend this radiator if you end up going down that road...



I talk a bit about it here...

Dan