New member as of today. Have always read threads and used much of the knowledge passed around on site. I have always owned and driven Rams. Just purchased a 1998 Ram 1500 4x4 with the 5.9. Truck came from cold country, Utah and I live in warm country, Las Vegas NV. Some days the truck will run about 150 degrees. Temp does not fluctuate at all whether i am in stop and go traffic or on the freeway. On other days the truck will run from a starting temp of 150 and rise to just below the white line on the hot side. It will then rapidly drop down to 150.....and the process repeats, again it makes no difference if i am in stop and go traffic or on the freeway. So yesterday i took of cap from radiator to check and add fluid and as usual for every couple days i am 3/4 to a gallon low. While waiting for fluid to drop, i start engine and instead of dropping to flow past thermostat, it burps fluid out. Then this morning i fill overflow and drive to work. Truck runs cool for 5 min and then does the up and down fluctuation. Arrive at destination and truck is pushing fluid out of radiator and completely empties overflow on ground. As an added note some days you hear water running through the heater core in cab and other days you do not. Truck has never actually overheated, just spits fluid and fluctuates. I do all my work myself and am hoping that i can get some of the solid advice that i have relied on from all you fellow dodge owners! Ambient air temperature in all cases is around 80 deg. Thanks for reading.

 

I'd start by installing a new 195 t-stat and go from there. Stant super stat.

And welcome to DF !

 

Have the thermostat and will be replacing this evening. Thanks for response!

 

I don't know what brand you bought, but if you have a candy thermometer in the kitchen, check the t-stat.

 

make sure you get all the air out of the system too, as you probably know. Maybe even get the front of the truck pointed up a hill. Don't want air trapped right around the thermostat.

 

Again thanks for the responses. As an added note, just drove for about 10 minutes and temp was still fluctuating and turned the heater on and it only blew hot air while under power. Heater core flush?

 

Ya a heater core flush wouldn't hurt anything. Go for it.

 

Well that might be a different problem, fix the original one first. You say "temp was still fluctuating " Is that after replacing t-stat?

 

No Zman I have not replaced the thermostat yet.

 

Your baby needs burping...