A.C. Heat Exchanger as Additional Heater Core?

[Logical1]

My 720 has the A.C. heat exchanger still in place even though I deleted the pump. I don't ever want A.C. however, the blower motor does blow past the heat exchanger on its way to the heater core. I could use more heat! Rather than removing it and fabbing up some ducting to get directly to the heater core, I was thinking it could be possible to route coolant through the heat exchanger and get a double dose of heat! I don't know shit about A.C. systems as I always delete them. Can the heat exchanger take the coolant running through it? I'm sure it can take the minimal pressure of the cooling system just not sure about hot glycol running through it. Thoughts? 

[RetroRocket]

On 3/15/2022 at 11:21 AM, Logical1 said:

My 720 has the A.C. heat exchanger still in place even though I deleted the pump. I don't ever want A.C. however, the blower motor does blow past the heat exchanger on its way to the heater core. I could use more heat! Rather than removing it and fabbing up some ducting to get directly to the heater core, I was thinking it could be possible to route coolant through the heat exchanger and get a double dose of heat! I don't know shit about A.C. systems as I always delete them. Can the heat exchanger take the coolant running through it? I'm sure it can take the minimal pressure of the cooling system just not sure about hot glycol running through it. Thoughts? 

It is an aluminum core unit as are modern radiators. So why not?

On the other hand, you shouldn't have to supplement your own oem heater core. You could end up with less heat delivered, more absorbed by materials. Why is your coolant either too low or not warm enough?

[datzenmike]

Many years ago I used a home air con condenser for a heater core on my 521. It REALLY put out the heat!!!!!!

 

Replace the thermostat with a 180-185 F

 

Pull the hoses off in the engine compartment and turn heater to full hot. Put a garden hose to one hose and blow the crap and sediment out the other hose. Now reverse the flow. Keep going back and forth till only clean water runs out.

 

Be sure the flap gate and all linkages are adjusted and working. The levers may be 'all the way' but internally not. Check that the heater core is not blocked with pine needles and maple keys, and mice like to nest in there too. Same in the plenum where the wiper linkages are... be sure the air can get in.

[SWFL]

My almost 100% original $150 1987 Honda CRX with 175,000 miles ( I bought it in 2002, needing a clutch and head gasket ), had almost no heat, when I went to use it in the winter. I remembered that it wouldn't pass SMOG ( Thanks POS Deukmejian! ) initially because the original copper/brass radiator was clogged up with aluminum oxidation, from the engine and was causing high enough NOx numbers to fail.

 

I figured out a way to clean out the heater core without removing it from the car. I got some long heater hoses and a clean oil drain pan. I rigged up the hoses to the open hood and attached one to each side of the heater core. I used both CLR and Lime Away separately. I would fill up the core and let it sit over night, then use my mouth to blow it out from one side into the drain pan. I'd water flush and refill the core with the other product and let sit overnight. Then I'd blow it out the opposite direction the next morning. I'd recover the products and filter them with coffee filters. I did this for a week and collected an amazing amount of oxidation crud. The heater core & radiator were acting like filters, as they both had very narrow flattened oval/rectangular tubes, that trapped the oxidation.

 

After cleaning the heater core, the heater could easily roast you out of the car without the fan being turned on high, even in the winter in the Sierra Nevadas. The heater core is tiny on those cars. Amazing how efficient they are when everything is working as it should.

Edited February 19, 2023 by SWFL

[datzenmike]

Always use an anti freeze coolant mix and distilled water.