Is there not an argument that in over cooled systems, such as a 200TDi than blanking off some of the radiator with a cowl will assist in getting the coolant up to temperature more quickly? It is generally accepted that those who have electric fans fitted, find they rarely switch on. That to me shows that the theoretical differences between mounting a fan in front or behind the radiator, are not relevant in a practical situation. Since this discussion has taken place, I have found a couple of sites that have said that mounting a ducted fan behind a rad can be up to 30% more efficient, however in an overcooled system, that would mean that the engine may never reach its most efficient operating temperature and the gains in cooling efficiency are outweighed by the loss of engine efficiency, the build up of sludge and the lack of heating (dig at tratta drivers ). As stated above - if it works, whether in front or behind, then it is fine.
My argument was not with which is the most efficient method, but with the statement " Do Not EVER fit a 'push fan' to any rad."

The reason the fans are normally mounted behind is because it is the most efficient as through the use of the duct it ensures the full surfaces of the radiator is being cooled and the fan is doing its job properly than wasting a lot of its airflow and power that would be required to over come the air loss from mounting it to the front. having a fan fitted to the front would be no different to running without your fan shroud on. It will still cool but just not as well.
The cooling system setup on a vehicle is built to cool not only through heat absorption into coolant but also act almost in the same way as a air con system by having areas where pressure is reduced in order to cool.
Diesels will run cooler than petrol and even when i think back to my old training days at Mitsubishi they warned of running their diesel vehicles for prolonged periods at idle as it would cool the motor too much

The Mad Hat Man said:

... My argument was not with which is the most efficient method, but with the statement " Do Not EVER fit a 'push fan' to any rad."

Click to expand...

A personal statement based upon a year or two's experience!

OSD