yukon 5.7 luke warm heat and low temp gauge

I have 97 GMC yukon 5.7L 4dr 4wd 1GKEK13R5VJ761161

It has alwasy leaked coolant around the block heater for the last 60k and i top it off every few months, maybe 3/4 of a gallon occasionly i forget about this and it gets to the point of no heat in the cabin and the temp gauge bouncing around. I know this isnt the best thing for the car, anyways i filled it up about 1.5 gallons and have been driving it for about 3 day now 50 miles a day. The first issue i noticed was my temp gauge will barely move above 100 now and prior to filling it, it would jump to 200 before kicking back down. The second issue is that i have luke warm heat in the cabin. I havent really used the heat since last winter but it normally cooks you out of the car.

Modifications to the Cooling system are Dual 13" electric fans, they do not come on right now though. I even pulled the fuse to be sure they werent the cause.

Any help is appreciated as its starting to get really chilly out.

DR

Sounds like your t-stat is stuck open.

thanks, i was thinking the same but thought it odd since i just replaced it 2k ago when i had to replace the intake gaskets, i did not use any RTV silicone. but its probable its faulty too.

Do you think this would cause the engine to never get to operating temp assuming the temp gauge is working still even after driving 20 miles? doing 75mph or sitting in the fornt yeard idling for 30 min after driving it?

yup, On a cold start you can look into the radiator and see if there is coolant flowing. You might have to rev it up a little to see it. If there is the stat is stuck open.

yup sure can, thanks for the help, ill be taking that t stat back.