At What Temperature electric fan designed to cut in?

[GazCaff]

As you know I am doing the 24V conversion and I had a viscous fan on my old 12v engine, but 2 electric fans on the new 24V lump which had aircon, I am going to use the electric fans in the conversion but what type is better??

A viscous fan will always sap a (small) amount of engine power. Electric fans only put additional load on the engine (via alternator) while they are operating.

I personally believe though that a viscous fan allows better heat regulation than an electric fan - when done right and MB seem to be better than most which is bourne out by the fact that they have persevered with a viscous fan long after most marques dropped this cooling method.

 

[W L Ow]

To GazCalf, I certainly see and agree with you with regards to electric cooling fan. I would also like to thank Siverarrow for the idea of installing a modified fan relay. I have not heard of such modified relay in Malaysia.

Having experienced overheating problem and replacement of the air-con compressor very recently which burned a hole in my pocket, I am now thinking of modifying the wiring to the electric cooling fan by adding a relay just outside the fan such that whenever the air con compressor kicks in, the cooling fan will be connected directly to the 12V supply from the battery so that it will, I believe run at maximum speed. When the air con compressor is at rest, the normal variable speed as controled by the fan controller remains.

Any advise how this could be done and any "side effect" on such modification? Note that I only have very basic knowledge of electricity and electronic.

PS. Sorry for the bad pictures in my last post because I had to crop the pictures to size in order to fit into the size limited by the Forum.

Thank you in advance.

 

[grober]

Before you modify your wiring think on the following facts. Before the overheating incident, did your car run OK temperature wise. If it did previously then it should run OK now IF you have solved all the cooling problems. I would still advocate a partially choked radiator as a potential problem. You could try back flushing as it would not cost much to do. Before that you should try to identify the mystery plug since it might just be the cause of your problems. Its not your inlet air temperature sensor is it ? ? as it has a similar shape. I dont dont know where its located on your model.