1994 Sea Breeze Automotive Air Issue

[CBRES]

Automotive AC runs super cold until 454 comes to operating temperature, then it is cool at best. Mechanic had previously replaced bad compressor, clutch and various valving. He now say that the hot water continues to cycle through the heater even after the Heater Valve is closed. He suggests an isolation valve to not allow any hot water to circulate in the heater core and that would cure the problem. Any thoughts if we are on the right track

Russ

[BFlinn181]

It's very common to have that heater control valve not shut down 100%. Putting in a ball valve to stop coolant flow through the heater core is something done on almost every school bus I ever drove. Go ahead, it will stop the heat. If you want to be clever, try to install it in a place you can access from inside so you can turn it on when you need heated defroster.

[Rook]

When I owned a GMC Suburban 454 V8 tow vehicle, I had the same problem. The fix......a simple inexpensive "manual" on-off valve installed in the water supply to the heater core.....works GREAT! Rook

[CBRES]

Bob & Rook ---
Put the 1/2" ball valve in on Sunday and I got a nice cold even temperature at all engine temps. Thanks for the easy, inexpensive fix

Russ