Hello, I have a 2002 Ram 2500 with the 5.9 v8 that is not will not get above 130 degrees unless i fully block it off with cardboard, but when i cover it it goes to 215 degrees. I replaced the thermostat, and it still doesn't get above 130 at all. I drove it 4 hours and it will not heat up. I did replace the radiator this summer and it ran just slightly cooler. Does anyone know if it could be the radiator is cooling too good? The CEL is on for code 1281.

 

Code is for "engine cold too long." How old is the pump? If the radiator is new, did you burb all the air properly by jacking it way up on the passenger side? Have you checked the temp of the upper hose? How about the heater core hoses?

Even at 0 deg F it should warm up eventually, especially with a winterfront. I put one on my grille to heat up quicker with my 180 stat but it never really gets that cold here in the PNW.

 

What thermostat did you install? Wasn't a 'safety stat' by any chance was it?

 

The upper radiator hose was at about 110 By the radiator, and 122 by the engine side. Both heater hoses were at 125, and the lower radiator hose was at 90 by the radiator and 70 by the engine. I didn't burp it by jacking it up on the passenger side, I only had jacked up the front. The water pump is only about a year old.

 

It was an auto zone failsafe brand thermostat

 

It has failed then. Replace it with a stant superstat. Skip the failsafe fellers, they fail WAY to quickly.

 

Thanks for the great answers. Everything seems to be working expect the stat. Yep, I agree with HeyYou. Get a Stant or nothing.

 

+1 on using a Stant… they don’t cost much more, but the time and money you save by not having to replace it again (and again) is a win.

As a guess, I’d say the thermostat price difference is less than the cost of a second thermostat housing gasket, so even if you consider your time free, it’s a win.

 

I'd certainly opt for a 195 degree Stant Superstat, being in Illinois. I don't tend to purchase budget thermostats, so I have extremely good fortune using these, as they are very good and highly accurate -

 

I just ordered that one from the link you sent