Thermostat Question

[paccool]

Just finished doing the KDP fix and a new seal. Had the radiator cleaned and added some "water wetter" to the coolant. I put a new Cummins thermostat in last fall and it was working fine.



Since I put the truck back together, the temp doesn't get up to normal, stays at the bottom mark. Not sure why. My question is - when the thermostat fails in our trucks, does it fail to the open position as a fail safe against overheating? I'm wondering if there may be some crap in it from disturbing the system or if it failed. Guess I'll order another one, seems to be a little soon for a failure of the thermostat.



Truck is turned up and smokes pretty good till the temp gets up to normal, need to get this fixed.

 

[tugboatphil]

Stan,



I had to change a water pump a few years back. Decided to put in a new thermo while I was there. There was a small piece of paper that said to orient the housing a certain way, to prevent cavitation, or something like that. Naturally I didn't pay it much attention. How could the designers know more than ME!!



I had the opposite problem. It seemed like it took forever for it to open. Ran much hotter uphill than it had previously. Took it off the road before I ever had a chance to go back in and check it.

 

[Paychk]

I think the water wetter improves the heat transfer from the coolant to the radiator and the air. Check the water wetter and I think it will state that, if so then your system is just cooling better.



PS cleaning the rad, will have the same affect, & between the two your system is just running cooler.

 

[paccool]

But the thermostat should stay closed until the temp comes up to normal even if the wetter and clean radiator help it to run cooler. I don't think the truck will run so cool that the thermostat won't even open up, would it?



The water wetter said temps could be lowered as much as 20 degrees but that was when towing. Heck, the damned stuff may actually work!



Me thinks it is time to pull the thermostat and throw in a pan of water and boil it to see what temp it opens at!

 

[1stgen4evr]

Thermostats

You can bet your * that a thermo will stick in the closed position. You can kill an engine with a bad thermo. Some larger engines have two for that reason. I wish there was a housing that would accomodate two for the 6bt. I am running the original thermostat in my trucks but I think there is an upgrade that is supposed to help with the cycling up and back on the heat. I belive there was a post about it a while back. If you have any doubt, check it out. Luckily, you are not overheating.



What is water wetter. I never heard of it. I need to check that out.



1stgen4evr

James

 

[Tim1]

You know, I don't think Fail Safe makes a thermostat for our trucks. It would be good if they did. For the 50% more initial cost, I think its worth it. Would rather have no heat from heater than a boiling motor. Used the fail safes in toyota and they do fail in the open position like they claim. I think you have a problem there, as the thermostat will not allow and flow unless at temp, regardless of how clean or wetter water. Remember the job of the thermostst is to hold the water in the radiator so it can cool and not just run thru the system,likewise warming block to 192 degrees. Tim

 

[paccool]

James,



I've had thermostat's stick in the closed position and it aint pretty! That's not the problem I'm having though. I think mine is stuck in the open position as the truck is not warming up.



"Water Wetter" is basically a surfactant. It changes the surface tension of the water so it makes better contact with the metal and is supposed to increase heat transfer. The radiator shop told me I should try it. I know that it is used by some racers to help cool the engines, most tracks will allow only water, no antifreeze or other coolants so they put a little of this in to help.



Stan