Bypass or Not Bypass Heater In BB with A/C

[Jill G.]

I have a 67 BB 400 hp with A/C. I intend to flush the traditional coolant from the system and fill with the recommended Zerex G-O5 coolant. The car was frame off restored two years ago and a new heater core and radiator was installed. The car is rarely driven and a heater would not be used in Arizona. Consequently it was suggested that I should by pass the heater by disconnecting the heater hoses to the heater and evacuate the water from it. The reason for doing this is for the long term preservation of the heater from rust. As you know, it is a major project to replace the heater on a BB without removing the engine.

Will the A/C work properly if the heater is bypassed? Is there a need to bypass the heater to prevent rust over the long term if Zerex G-O5 is used? Your suggestions will be appreciated.

[Bill I.]

Re: Bypass or Not Bypass Heater In BB with A/C

Paul, sorry you're not getting any replies. It is my understanding that A/C cars have a heater by-pass valve already.When you pull A/C on dash, valve closes. Bill.

[Wayne W.]

Re: Bypass or Not Bypass Heater In BB with A/C

My guess is, the inside of the core would probably corrode more dry than with coolant in it. The AC will work equally either way assuming the cutoff valve is working correctly.

[Dick W.]

Re: Bypass or Not Bypass Heater In BB with A/C

From experiences learned in another life as a radiator shop owner, if you leave the core open with no coolant in it, you will experience corrosion faster than you will with coolant in it.

[Ken A.]

Re: Bypass or Not Bypass Heater In BB with A/C

Since you live in AZ, you should flush the system and fill w/ DISTILLED water and a rust inhibitor. Your car will run cooler & system will last longer.