I bought my 99 Blazer w/130k mile on it several months ago.

I was having issues with the heater back then and had the Thermostat replaced with a new 190 degree unit. I also did a reverse flush of the heat core as well.

After that, the heater worked ok.

Recently, it's been in the single digits here and my Blazer is now NOT throwing out heat like it should.

After driving for 1/2hr on the highway today, I pulled over and felt the hoses to see how hot the were. Both heater core hoses were luke warm. The top radiator hose was NOT very hot either.

The water temp guage runs a couple lines below the 210 mark. I'm guessing around the 180 degree range.

I thought about putting a piece of cardboard in front of the grille, but it would be a PITA to do so.

How do I get this truck to heat up ???

 

Dude clamp on the 2 heater hose on the firewall remove both hose's and blow air inside the heater core or put a garden hose on it to flush it clean,i live in laval quebec and i ave to do this every winter or else i dont get good heat and freeze inside the truck

 

It's worth a try. Most heating issues stem from a clogged heater core as not all of that hot coolant is getting through due to a clogged passage.

Push water both ways through it to get most of the gunk out. Make sure you get the air out of the cooling system when your done.

 

Try flushing out the heater core like said above, hopefully you dont have a bad heater core because those are a pain to change!!(mine went out a month ago). But as long as you have no antifreeze smell in the cabin or a foggy windshield you should be fine.

 

check your radiator cap if it holds pressure if not replace cap ,if theres no pressure in your cooling system it will not circulate properly