Strange cooling question-motor won't warm up in winter.

[Yukonboy2014]

Howdy y'all,

I have an '01 Yukon with the 5.3. 255k miles. She burns a little oil and coolant and needs a rebuild..but that's beside the point. My situation is that in the winter, when its about below 50* out, it will never get warmer than the next bold mark between 160* and 210* on the gauge and I have no heat in the cab. I replaced the thermostat this summer, hoping that would fix the issue for this winter. But I've noticed it still takes about 8 to 10 or so miles to come up to 210* even in the summer, 105 out. And our 05 suburban is already almost to 210 before we drive out the neighborhood, about a mile from the house. It only has done this the last winter. Besides suggesting to flush the heater core and change the fan clutch(changed bout 45k ago, it's not locked up), what else could possibly be the culprit to this problem? any help would be greatly appreciated!

Hollis

 

[loaner2]

Check to see if you are building pressure in the radiator overflow tank. Had a similar problem with no cabin heat, didn't apper to be building much pressure in the system. Flushed the heater core and had no apparent blockage, refilled and replaced the overflow tank cap, had noticeable pressure and had instant heat.

 

[OR VietVet]

X2. For every lb of pressure the rad cap holds the coolant boiling point raises 3 degrees and having a sealed system is important. Flushing the system now will likely not do anything. Flush is for maintenance, not repair. Besides the engine coolant needs to be hot enough, if your readings are correct, to get the hot air from the heater core. If your temp is that low then try a partial blockage in front of the radiator, cardboard, and then drive to see if the temp gets better.