I have a 88 Chevy K2500. Thermostat is working fine and system builds up adequate pressure. Coolant levels are right on target.

The heater is supplying warm air, not hot air to the cab. The intake hoseto the heater core is very hot and the return line to the radiator is considerably cooler. I understand that this is the way it is supposed to be.

However...I feel the return line is cooler then what it should be. Is it possible that I have a restriction or low coolant flow to the heater core? I just replaced the heater core as the old one 'blew', but I had the same problem with the previous heater core...just NOT enough heat to the Cab.

Any thoughts would be greatly appreciated. Thanks!

 

Carter56,

Maybe a heater control valve, it controls how much hot water passes thru the heater core. I think it's inside the cab above the passengers floor area. I'm no mechanic but that's where I'd look.

Dennis

 

is the core secure in the box?...I've seen em sag,letting cool air behind them

 

It could be the blend door in the heater box not switching all the way to hot.. They are adjustable to a certain point.

 

should be a cable driven vent.