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mk1collector

Member Since: 17 Sep 2009
Location: West Yorkshire
Posts: 6769

Air con fan

With the air con fan being on the front of the radiator should it pull air into the radiator (Towards the back of the car) Or away (to the front of the car) from the radiator?

Cheers
Ray Ray
My build thread
http://www.defender2.net/forum/topic17615.html

17th Aug 2020 5:00pm

Matt110

Member Since: 29 Jun 2014
Location: UK
Posts: 685

Into the engine bay

17th Aug 2020 5:22pm

mk1collector

Member Since: 17 Sep 2009
Location: West Yorkshire
Posts: 6769

So pushing the air through the air con rad and water rad? That’s what I thought it should be. Must have wired it back to front

Ray
My build thread
http://www.defender2.net/forum/topic17615.html

17th Aug 2020 7:24pm

Matt110

Member Since: 29 Jun 2014
Location: UK
Posts: 685

That's it. The idea is that the first heat panel to see the air flow is the condenser, so you blow through the condenser into the rad pack, though the thermoviscous fan "pulls" through the radiator from the other side too when the engine gets warm. Condenser fan is a pusher, the thermoviscous is a puller.

17th Aug 2020 7:55pm

mk1collector

Member Since: 17 Sep 2009
Location: West Yorkshire
Posts: 6769

Part two of my question then.... what determines if the air con fan is on or off? Reason I ask is, after driving about a fair bit today, I got home and about half an hour later I went back out to the car and the air con fan was running! I switched the ignition on and the fan went off, switched the ignition back off, the fan started up again. Went out for a drive and stopped at a shop, switched ignition off and fan came on again. This happened a few times as I made stops but the air con isn’t gassed up and the switches were off. I thought it might be temperature related but not sure. Ray
My build thread
http://www.defender2.net/forum/topic17615.html

17th Aug 2020 9:14pm

Matt110

Member Since: 29 Jun 2014
Location: UK
Posts: 685

Top hose temperature.

When you key off the water pump stops with the engine. That means that the radiator top hose gets very much hotter than it normally would due to the circulation having stopped but the heat still soaking out of the engine block into the coolant.

Most cars have run-on functionality whereby they'll monitor the top hose temperature (or work it out by algorithm based on atmospheric temp plus block temp) and run the fans on once you've keyed off to avoid the top hose from experiencing such high temperatures.

The complexity in that is when you've got a thermoviscous fan not a "normal car" approach of having electric fans that do both condenser pack and the main radiator. I.e. a defender.

On a defender to do the same thing the only tool available would be the air conditioning condenser fan which would push air through the rad pack, albeit rather inefficiently due to the relative heights and the air gap between them.

Not had mine do it... Even in very hot weather and towing.

.....so having spouted all that, it could we'll not have that functionality and actually just be a different issue!

17th Aug 2020 9:23pm

mk1collector

Member Since: 17 Sep 2009
Location: West Yorkshire
Posts: 6769

I’ll switch the wires around on the fan and see if it cools better and maybe only kicks in for a while. Thanks for the reply’s

Ray
My build thread
http://www.defender2.net/forum/topic17615.html

17th Aug 2020 9:26pm

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