Modified Cooling system arrangement.

[John Morrison]

23 minutes ago, John Mellor said:

Never been able to understand why so much trouble from overheating. My Police tr4 has factory standard system and never overheats even crossing central Spain in the ferocious  Spanish summer.

Clogged waterways, engine set up, lack of airducting in front of rad thermostat plus other causes wtf. Still as long as overheating i suppose that's all that counts

Jon M

 

+1 efficient, maintained original system works fine.

John

[Chilliman]

Interesting views expressed here. I personally use alloy rads but that is purely for the benefit of the weight reduction they give at the very front of the car not for the cooling benefits which I suspect are no better (and possibly not as good) as the original system if it is well maintained....Hard hat on - prove me wrong.....

[Drewmotty]

Sounds about right John. 
Modern cars use aluminium rads for two reasons, weight saving and cost. Nothing to do with efficiency. 

[Andy Moltu]

On 2/13/2026 at 7:42 PM, Drewmotty said:

Sounds about right John. 
Modern cars use aluminium rads for two reasons, weight saving and cost. Nothing to do with efficiency. 

Add to that you can more easily produce more complicated shapes cheaply in aluminium to increase the surface area for heat transfer which does go some way to mitigating its lower thermal conductivity. Copper conducts heat at roughly twice the rate of aluminium, however that may not apply to the specific alloys use. If we assume this is the case, the other consideration is how thin the radiator can be constructed. 

Of course this all assumes that the rate limiting step is the transfer of heat from the water in the rad to the air outside.

 

[Drewmotty]

My TRs tend to overcool anyway so in real terms the rate of heat transfer probably makes no difference. 

[Hamish]

1 hour ago, Drewmotty said:

My TRs tend to overcool anyway ……

Now you are just showing off !! 😉 🤣

[iain]

9 hours ago, Drewmotty said:

My TRs tend to overcool anyway so in real terms the rate of heat transfer probably makes no difference. 

Agree, even on very long days in France Spain and Italy where it’s tends to be pretty warm.

In the 3 I can see from the action of the temperature gauge needle, when the thermostat opens and closes whilst driving. Not just from cold start up.

Edited February 16 by iain