Heater

[Chrispbrown36]

The heat in my 1987, like many others, is great....maybe a little too great. There is no middle ground with it....it's either hot enough I could broil chicken or blowing cold air. I have tried just barely bumping the hot/cold switch over until it cools off but the temp never drops til it switches to cold air.....anyone else have this issue?

[Chrispbrown36]

One more question.
Monday morning woke up to 11 degrees outside. Started the truck up let it run for 15 minutes (more than enough time to get it up to temp every other time) went out to check and windows still frozen up and no heat. Ran 15 minutes more while I got the wife's car started....still iced up and no heat. Broke out the ice scraper got it cleaned up enough to see. Started down the road and less than I mile later the temp had shot up to nearly 260, so I headed home. Later that day I drained the radiator, put in a new thermostat, and filled it back up with anti-freeze. Before the temp held solid at 195 with no fluctuation in the gauge, now I can actually see the thermostat kick in....the temp will climb to the 210 mark and then drop back to 195. The temp also doesn't start to rise until I start to drive...just sitting and warming up it won't climb much at all.
Any ideas?

[tucsonjwt]

I don't know what your problems are, but:

I have found that removing the heater control from the dash and fiddling with it (jiggling cables and connections) while in use often will detect problems intermittently -meaning you have a wire/connector/cable problem.

One possibility on your overheat problem is that your radiator is clogged. I had this problem on my old Cavalier recently. The temperature would rise up at highway speeds, and creep up in stop and go city driving. Even though the coolant was flowing through the radiator, there was not enough flow to cool the engine down when it got very hot.

You might have a bad water pump, but you should be able to see a rusty trail at the weep hole on the bottom side of the pump if that is the case.

Like all of us with old vehicles, you may find that you have more than one problem.

[Chrispbrown36]

I ran fresh water through the radiator before I put fresh antifreeze in it until it came out clear. A lot of rust colored water came out but no major chunks. I am fairly certain that the radiator was replaced when the previous owner put in the new motor...it just looks too clean to be the original radiator.
I love how the water pumps on these trucks have weep holes on them....that way you at least have a little bit of a heads up when it is going out. No weeping so far.....one of the first things I looked for. I am fairly certain that the thermostat needed to be replaced and really I need to flushed the whole system, but right now that isn't going to happen. I am going to try a different thermostat to see if I can the temp needle to stop bouncing.

[Chrispbrown36]

Well, I swapped out the thermostat, again. Now the truck is warming up faster and is holding a solid temp, though it is not at 195 like it was before. As long as it holds solid, I guess I can live with 210.

[86c20]

what one did you use? got a part number? i have a 205 tstate and it takes for ever to get to temp after the first open. seems to close at to a real low temp like 160 so no damn heat lol

[Chrispbrown36]

This is the one I put in....http://shop.advanceautoparts.com/p/s...erm=thermostat

[tucsonjwt]

I sprung for the expensive "fail safe" style thermostat the last time I installed one - not relevant to your problem, just a thought on not having a thermostat fail closed rather than fail open.