I have a 98 Bravada with a heater problem. Let the car run up to temp for 20 minutes and still could get no heat from the heater or defroster. Scrapped the ice off the windsheild and started driving. As soon as I got to the end of the block it was blowing hot air. How can I fix this. I did notice the temp gauge fluxuating a lot while driving. Good temp but moving 20 degrees back and forth a lot. Thermostat?

Start by making sure it’s topped off with coolant. Then the thermostat is the next likely culprit. After that, I’d suspect water pump.

I agree with Josh. Likely it is one of the three. He also has the right order.

I’ll try those ideas and let you know.


I was low on coolant because the upper inlet is cracked and leaking. Correct me if I’m wrong but I’m assuming this can’t be fixed and the radiator needs to be replaced. I want to be sure I get a radiator that matches OEM standards (core thickness, number of rows, etc). How can I be sure? Where can I find the specs?

Any radiator shop or automotive parts house has a catalogue with your make and model. Make sure you tell them what powerplant your car has and that it has A/C. Also, if you have a trailer towing package factory installed. These items determine the size and configuration.

I’ve found plenty of radiators on line that will fit but one of the big discrpencies is core size. Everything from 16mm to 1.5 inches. I live in Texas so I need to make sure I have the proper core for the summer months. Is a thicker core size better?