my dad has a 98 cummins diesel quad cab 4x4 and it will never get hot! he has a winter bra on the front cardboard in front of the radator and plus but a 180 degree thermostat in and it still wont get warm at all! i have a 99 24 valve and about 5 mins its blowin hot air! just wanted to know what the difference is or what was going on thanks!

 

Change the thermostat.<br><br>--Justin

 

its a brand new thermostat!

 

What PourinDiesel said<br><br>some new ones are defective . <br>remove<br>Wash it clean for Moma <br>put in a pan on the stove<br>check opening temp with a candy thermometer.

 

should have know its a &quot;napa=junk&quot; thermostat! have to check it out first but probally is junk! everytime we go get anything at napa it is the wrong part and have to take it back or put it in and its junk! they never have anything for dodge period! i spent so much money and time there putting my 93 back together it was just a big waste of time! all there books say dont have it need to go somewhere else or they got 10 different parts u need to have a number! didnt have front and rear u-joints for it! its a 60 front and 70 rear come on!!!! and the king pin set up on the front needed the nylon bushings nope napa doesnt carry them ok how long has dodge been running that set up for more than 20 years in there truck!! grrrrrrrrrrrrrrrrrrrr!!!!!!!1 &gt;

 

so r u saying the one from the factory is junk to cause the truck from day one when he got it from the dealer never has gotton hot. i dont know it just sounds weird. thanks for the help guys!!

 

Hay check your hoses going to the heater core to see if there both about the same temp if the core is blocked up one hose will be hotter than the other an this tells you that your heater core is blocked shut. If so try back flushing it.<br> just a suggestion Bob

 

Just a suggestion-<br><br>If you determine the thermostat is bad, get one at a real truck store like Truck Pro or Fleet Pride, etc.