Bad Thermostat?

[rboltz]

The truck is back on her feet and today I rolled her out for some testing and to reverse it in the shop. Wiring finished and tested and new plumbing under the hood. The truck had no thermostat in it from the PO so we put a new one in there. Now it overheats. No water flow to the radiator. Radiator and hoses are cool while the temp gage is pegged. Can it be a new thermostat that is defective or since the system was drained can it be air bound? The thermostat housing seems hot but it isn't opening. What temperature thermostat should be in here? I put a 180 in but we ran hotter then that!!

[airborne]

Once it cools down, I'd crank it up with the cap off and see if the water starts to flow when it opens. Also with the cap off, any air that might be in there can get out. (Also if you have a heater, place it on warm/hot, that can help get rid of air trapped there as well). If the water starts to flow at around 180 deg's, it could have been trapped air. If at around 180 deg's, you don't see any flow, it could well be a bad thermostat, or bad water pump. If you pull the thermostat, just drop it in some boiling water on the stove, it should open right up. My,.02.

[rboltz]

Good thought on testing the thermostat in water. I sure hope it's not the pump as it's a new one and was working fine without the thermostat in there. I did get water flow without the thermostat but none with. I'll take it apart again and test it in hot water.

[brute4c]

I always check the thermostats on the stove with a thermometer before install...ither one of the digital cooking thermometers or a glass candy thermometer.

Is it possible the gasket or something got in the way? Probably not but...

The gauge shouldnt peg and of course there should be flow.

Might want to try randycycles trick and open the thermostat, like when its hot, and put a couple aspirin in the opening. This will give flow to start and help get rid of any air bubble AND will disolve away harmlessly after that.

At least you would know if it is the thermostat not opening or something else...like the water pump...

[george walker]

Just for the info. the 230 uses a 190 therm., and the cap is rated at 13psi.

[rboltz]

Yes, it is a 190. Typo on the 180. It's a NAPA TM183.

[brute4c]

I run a 195 with a 15 lb cap and a 60/40 mix due to my climate...helps get a little more heat.

[george walker]

On a related note here is an interesting article about modern coolant types, an the confusion about what is the right type for your car, it is a bit long though. Also you shouldnt use more than 70% antifreeze in the mix as it will begin to lower your boiling point.
http://www.geocities.com/dtmcbride/h...ntifreeze.html

[brute4c]

I try to get 60-65%......usually 3 quarts coolant to 2 quarts water....never to exceed 4 quarts coolant to 2 quarts water.

Of course, it can get -25 or better here and I have seen it below 0 for over 100 straight hours more than once....in fact, we almost broke a record a few years ago because we had so much below 0 weather straight...in a whole week, 168 hours, we had 1 hour where it warmed up to 0...that was over 140 hours into the week...it then dropped back to subzero for almost 72 hours. Had it not "warmed up", we would have broken the previous record by more than 25 hours.

Bottom line, "toy" antifreeze dont cut it.

[randyscycle]

I know this may sound like an obvious thing, but did you install the thermostat correctly? The copper "pellet" should be on the engine side.....Just a thought.