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Fitting modern hvac unit to old car

Posted: Sun Aug 24, 2025 3:33 am
by Benzina
Hi all,

newbie here. Got an old 70's Jaguar and instead of reconditioning the tired hvac unit I thought about fitting a unit from something modern like a Mazda. I'd want to use the Mazda control panel but wonder how simple this whole exercise might be in practice. Not worried about fitting, can make that work and will be rejigging the dash to accomodate.
Has anyone done something like this?
Thanks, Dave

Re: Fitting modern hvac unit to old car

Posted: Sun Aug 24, 2025 8:39 am
by Tim
You will need to make a mounting bracket for the compressor in any case. Just get a unit from Old Air Products, Nostalgic AC Parts, or Vintage Air and start your fabrication from there. I've been involved with many custom systems back in the day. Nothing magical about it. Just fabrication with the items you're using.

Re: Fitting modern hvac unit to old car

Posted: Tue Aug 26, 2025 4:31 am
by Benzina
Hi Tim,

thanks for your input. I have fitted Vintage Air to a few cars but wanted to get away from that "old style" set up and use a more modern system. Compressor bracket is no problem as that is being moved anyway. Might get on to Denso and see if they can help.
Thanks again.

Re: Fitting modern hvac unit to old car

Posted: Tue Aug 26, 2025 7:18 am
by Tim
What's so modern about a Mazda A/C system?

Re: Fitting modern hvac unit to old car

Posted: Wed Aug 27, 2025 12:35 am
by Benzina
The Mazda was just an example but is a system I'm a little familiar with. Not sure if they are a self contained unit or run through the ecu. I find the Vintage Air units ok but the controllers are quite lo-fi and not what I'm after. Trying to bring this car into the 21st century.

Re: Fitting modern hvac unit to old car

Posted: Wed Sep 03, 2025 9:46 am
by JohnHere
If you can locate a complete Mazda A/C system from about 10 or 12 years ago, it will be a *self contained* system using a fixed-displacement compressor that is not ECU/BCU controlled. Anything later than around model year 2016 will have a variable-displacement compressor and ECU/BCU control.

The latter system will be virtually impossible to install in your 1970's Jaguar because cars of that vintage were not computer controlled to begin with. Even if you did attempt to install an A/C system and an ECU from a late-model Mazda, it wouldn't work for reasons too numerous to post here.

I recommend taking Tim's advice and use a non-computer-controlled custom aftermarket system that will simplify your project considerably.

Re: Fitting modern hvac unit to old car

Posted: Sat Sep 06, 2025 7:38 pm
by Benzina
Hi JohnHere,

thought I'd replied to this. Thanks for your input, that is the answer I was hoping for. The vintage air unit itself is fine but want a more hi tech control panel. The car does run an ecu which will be updated but a self contained system would be easy to work with.
Thanks again.