Inside Heater Issues

[miiller]

Hey I have an 2004 Chevy Silverado 5.3 with dual climate control. The engine warms up normally, but after about 15 mins the heat fades to cool air. After a little while it will usually turn back to heat. Sometimes you can adjust the temperature controls and get it to blow warm air. Its been doing this for about one year and a half. About six months ago my engine over heated twice and I found out that my coolant resivour was empty and it took a gallon to get the whole system back to full. Now I have noticed that my resivour is not as full as it was, so the system is taking a little bit more, and like I said I still have not seen any leaks. I'm not sure if these two are related but I wanted to make sure and give all the information I could. Have any idea what is going on with my truck? Thanks

[txab]

If you're low on coolant the heater core will exhibit low heat or no heat. You need to find out where you are losing coolant.

 

Check:

 

Water pump and gaskets

All hoses and connections

radiator.

 

Also look at this search on the subject of coolant loss with Castech heads. Your 2004 model year is one of suspect years.

 

Coolant loss Castech heads

 

You could also have a blend door problem. But I'd for sure figure out where your coolant is going and do it soon