Questioni have a 1998 chevy tahoe, replaced cracked radiator two days ago. since then after adding coolant, when you turn heat on it never gets warm, you can run for hour or so still no difference. when i added water should i have had heater on, or would this make that big a difference? don't know what to check next, vehicle was run to about 240 a couple of times.no leaks out exhaust or underneath.
AnswerHello David,
It is more than likely going to be a pocket of air trapped in the heater core.
Probably the most positive way to bleed it out, is remove the heater hose from the radiator, where it returns coolant from heater to radiator.
Hold the removed hose end above the level of the heater core, or like above the lower edge of the windshield...then you are sure.
Connect a garden hose to the little nipple on the radiator where the heater hose was removed.
Slowly add water till just coolant flows from the raised heater hose. You can catch it in a bucket.
Reconnect the heater hose to the radiator.
If you don't want to dilute your coolant with water, use a radiator pressure tester to force the coolant through the system, but you will need to plug the hose nipple on the radiator where the heater hose goes, with a cork, a thumb, or a rag.
After reconnection the heater hose, top off the radiator with coolant mix.
Van
