I bought a '99 Zr2 a few weeks ago and have driven very little. Today however while driving the heater was luke warm but not warm enough. I don't know what the increments on the temp gauge represent in degrees. I've read that they are 14 degrees left of center and 6 right of center. From 100 it reads 5 and a half ticks. That would be 177? That's not very warm. I was thinking maybe it was the heater control but when turning it back from max heat it get colder fast.
So am I right on what the gauge is reading and is the thermostat what's causing the heater to not be hot? I have an '86 Blazer with a 180 degree thermostat in it and it gets plenty warm, but it runs about 190 normal.

Thanks

 

Heater core bunged up, not circulating fully. Very common, not fun to replace though. I've done it in all three S-series vehicles I've owned. Get a proper flush done when installing a new one so you aren't circulating garbage through your new heater core.

 

Thank you for the reply. The heater "works" it just doesn't seem to get as hot as my other cars. What temperature do you think it's running at?

 

First step should be to connect a scan tool and check the ECT, (Engine Coolant Temperature) sensor live data stream. Normal coolant operating temp for your 1999 should be 195F to 200F.

 

I would still do a flush of the heater core. Low flow will result in low heat output.

Flush is an easy thing to do...a bit messy, but easy. Just do not use high pressure or you might find the passenger footwell to be full of water. The heater core has small passages...just use a gentle flow of water.

 

" I've read that they are 14 degrees for each tick left of center and 6 right of center. From 100 it reads 5 and a half ticks. That would be 177?" The numbers on the gauge certainly don't look like 195-200 then. So maybe the thermostat is stuck open. (grasping at straws). Also if the heater core was plugged wouldn't that cause the engine to run hotter?

 

Heater core has really nothing to do with engine cooling....yeah....with the heater going full blast the engine coolant will get a cooler...for awhile; doubt the temp gauge would show much difference though.

 

Raysrh who says your temp gauge is working perfect??? Please listen to the advise your being given.

 

Thank you for all the replies. It appears there is nothing wrong with my heater, thermostat or gauge. It was just me. It just didn't seem as hot as my other rigs and since I haven't had it long I was not secure with the way it felt. After checking everything it turned out it was my imagination!


Nevermind

 

You sure your thermostat is good? I literally just had this happen on my '99 ZR2. Grabbed a $10 195 degree Stant thermostat and temperature gauge rose to what my '01 used to run at, lots of heat now.