Club 80-90 Forums

Hi All,
For a late WBX DG engine the heater Matrix runs in parallel with the radiator feed and return from the engine to the front of the vehicle.
The feed to both the radiator and heater come from the coolant distribution block,
The returns both head towards the thermostat housing. (Although I'm not 100% where the heater return went!!)

This might be a dumb question but has anyone ever just tapped off the radiator Pipework to avoid the need to run the additional pipes from the rear of the car to the front.

In my mind the heater Matrix is basically a radiator, albeit you have the choice to turn it on or off with the valve and the air is forced across the matrix via the fan to remove the heat into the cabin.

Am I missing anything obvious which prevents this from working?
Thanks.

If you were to follow this theory , you would have no heater un till the thermostat opened , and would not be Able to switch the heat off at all .

The heater pipes feed direct not via the thermostat and return to the cold side of the system

To put it another way, the heater is a full-flow thermostatic bypass system, allowing heat to be available in the cabin as soon as possible and while the engine is still getting up to full operating temperature (thermostat closed, no flow to main radiator)

VW and every other post-war automotive manufacturer using watercooled engines have already thoroughly developed this means of cabin heating. It works.

BigBlueVan wrote: ↑23 Dec 2022, 23:26 ...has anyone ever just tapped off the radiator Pipework to avoid the need to run the additional pipes from the rear of the car to the front (?)...

I had the same thought years ago and used one of the special radiator feed hoses with molded-in tee for the autotrans oil Hx. Of course the heater must have its own separate return, coming in past the t-stat so heater flow is always dispatchable by the heater valve. So you can only eliminate one hose run.

What I found was puzzling. The heater would never get nearly as hot as before, in fact in very cold weather it became inadequate. And we have lots of extreme cold weather here, so...

Pondered possible reasons, no conclusions, and since it offered little other benefit except one less hoses run, I put it back.