engine temp switch

[beastie_3]

There is no reason to run without a Tstat.

[74chev4x4]

OK so I just got  a new fail safe tstat and put it in tried to keep the  rad cap off for as long as possible then put it back on. The temp gauge said the truck was hot but I let it go for a few min longer cause it was just idling in the driveway.  The hoses pressurized so the tstat must have opened.  The only thing is its still saying the truck is running hot.  If i start to drive at all it says hot, stop and it goes down a bit, truck showed no sign of getting hot rad cap did not blow( brand new cap also).  I did notice that the top rad hose was really hot and the bottom was not really hot at all?  So do I have an air bubble or what?  Not gonna drive it till I get some feedback.  thanks

[beastie_3]

If the top hose is hot, and the lower hose is cooler, then your radiator is working.

I might go to your parts store and buy a cheap 25 dollar temp gauge and use that. Or buy a laser style temp reader and read how hot the radiator is.

[Irish_Alley]

There is no reason to run without a Tstat.

not saying its a bad ideal but when winter hits it will be bad since it wont warm up as much on newer cars its a can cause it to run rich but on ours right now theres no problem

OK so I just got  a new fail safe tstat and put it in tried to keep the  rad cap off for as long as possible then put it back on. The temp gauge said the truck was hot but I let it go for a few min longer cause it was just idling in the driveway.  The hoses pressurized so the tstat must have opened.  The only thing is its still saying the truck is running hot.  If i start to drive at all it says hot, stop and it goes down a bit, truck showed no sign of getting hot rad cap did not blow( brand new cap also).  I did notice that the top rad hose was really hot and the bottom was not really hot at all?  So do I have an air bubble or what?  Not gonna drive it till I get some feedback.  thanks

whats hot to you and your gauge?

[74chev4x4]

the radiator should be fine it was working great when I ran it today without the tstat, not sure how hot is hot its on the factory gauge in the truck and the sender is brand new.  It just gets into the red but if you shut it down or let it just idle it will go down a bit.

[Irish_Alley]

with the rad cap off does the coolent just flow or are there allot of bubbles?

[74chev4x4]

I didn't look when I just did it with the tstat in, but this morning when I ran it without the tstat it was moving through the radiatior really well had a nice flow to it.

[Irish_Alley]

are you using strait water?

[Irish_Alley]

also you ran it at highway speeds with no tstat with no problem?

[74chev4x4]

got it up to 45 mph, this is the same rad I used with my 454 and never had any problems. No using a 50/50 mix of coolant and water.

[Irish_Alley]

and what spped with the stat in till it over heats?

[74chev4x4]

It is almost hot just sitting in the driveway, take it out on the road maybe 20mph and the gauge says its hot?  I dunno why its such a difference with the tstat in, the thing ran super cool without it, didnt even get up halfway on the gauge without the tstat.

[Donut]

Thermostat is to maintain temp. (basically)
How's the fan and shroud?   How accurate is the gauge? 

[Irish_Alley]

Ok here's what I think. Your Rad is restricted or the water pumps fan blades are worn causing inadequate flow its enough flow with out the thermostat. But the thermostat it self restricts flow so. Red that's flow is restricted + thermostat = over heat or worn water pump blades +thermostat = over heating. I would say flush the system try it then or flush it and add a new water pump. Does that make any sense what ever the problem is its not bad enough to cause over heating unless its restricted with the thermostat and when you idling you engine doesn't require allot of water and your probably flowing just enough to keep it cool

[74chev4x4]

Its a brand new water pump actually the second brand new one I have put on it in a week just to be sure.  I almost think its an air bubble in the system, but how do I get it out?  The coolant is ready to come out the fill hole on the rad by the time its hot enough to start circulating through and I cant really get the air out if its not circulating.  God this truck stumps me all the time, I seriously think it likes to be in the driveway with the hood up more than it likes to be driven.