Okay I've been having a problem with my truck where when I start my truck and drive it doesn't get warm and the temperature gauge doesn't move till after like 15 min of driving and doesn't shift into overdrive. And when it does get warm it just cools all the way back down and the temp gauge reads completely cold and it shifts out of overdrive. I have flushed the truck 3 times and put 2 thermostats in it in 2weeks and the problem has yet to go away. My question is there a sensor that tells the thermostat to open and close because i don't know what to do? thanks for any input- zach

 

Is it getting up to temperature, and the gauge just isn't reading it? Or is it really running that cold?

First you need to find out. Run it awhile then take a temperature reading on the engine, see what you get.

If it's actually hot, you probably have a bad sensor or gauge.

 

If it was hot wouldn't i have heat. Because when the temp gauge is cool i have no heat at all its like the a/c is on. When the temp gauge goes up i have heat and the truck shifts into o/d like it should. Also when the temp gauge is down it idles at like 1000 as if you just started it and when the temp gauge goes up it idles normal like it should at about 600, and the top hose isn't warm at all. I'm thinking its something electrical but I'm stumped

 

Bump

 

I am having the same problem. How many gallons of liquid did your cooling system hold after you flushed it?

 

It took two containers of Prestone 50/50 green antifreeze.

 

I believe that the problem is that the radiator is not able to hold its intended capacity. Mine only held 2 gallons I believe a full cooling system is 4.5 gallons. I also temp gunned my truck ill post the results tonight when I get home amd ill check that capacity.

 

I don't know the exact amount I put in but if there wasn't enough coolant to circulate I would expect it to get hot, not run cold and every time I have flushed it it normally took about 2 containers so I'm not sure.

 

Yes that's what I thought too little coolant, engines gonna get hot. There was another post in the maintenance forum and it was suggested. Ill have to look up the capacity when I get home. This problem seems to be common. I have replaced the tstat 2 times first was a 195° and now I'm running a 210° no difference. When I temp gunned it this morning I got these temps. 44° outside air, 158° top aluminum structure of radiator. 153° top radiator hose. 151° lower intake manifold. 101° throttle body. 127° top of radiator cap". 155° thermostat housing. 459° driverside exhaust manifold about 3" away from the head. Temps taken after truck was warmed up for 10 minutes, driven 26 miles, then idled for 5 minutes. Truck was off for about 2 minutes then temps were taken within 3 minutes. Clearly this is not a normal operating temp. And I know that it is running cold.

 

when you are draining the anit freeze not all of it comes out of the drain plug...if you want it all out you have to disconnect the hose that connects to the bottom of the radiator..