Stag cooling

I installed an electrical fan in lieu of the mechanical one on my T-Bird and it did not work at all causing it to over heat in a big way, I put the mechanical one back on and left the electrical one on as well and it was fine, The electrical fans on older cars are great in city traffic as a back up, but my Dollie only has an electrical fan and it works fine

Dave M.: The flow rates quoted by aftermarket look good - but are almost always "zero pressure drop" flow rates, ie, how much air is shifted with nothing in front and nothing behind the fan. In a car of course, the radiator is there - and this can drop the flow rate to 1/2 or 1/3 of the quoted figure or even more. For example, a Revotec 10" fan has 738 cfm at zero pressure, 500 cfm at 0.015 psi, and 230 cfm at .03psi. Most radiators have a lot more than .03psi pressure drop....and it draws 9 amps at this low flow rate as well as the high flow rate. I know a 10" fan is too small for a stag, I merely use this as an example of the flow rate reduction with pressure drop. An electric fan for a modern 3 litre engine is typically 400w - that is, 30 amps running current at 14v nominal, probably protected by a 60 amp circuit breaker. A "very high power" 15.2 inch Revotec fan draws 20 amps - about 2/3 of that of an OEM fan. A good test for an electric fan is to hold the mounting bracket in your hand, and start it up. If it breaks your wrist and flies away because it's so powerful, it's a good fan. PS I don't recommend this test !! Personally, I have kept the OE fan and viscous clutch and factory shroud on my Stag.

Richard B.: About a year ago I had completed the mechanical side restoration of my 1974 mk2 manual Stag and have been driving it ever since. Earlier this year during summer here in Perth temperatures on one weekend went up to 39-41 degree. I had the Stag out for a 45 minute drive to lunch and the same after lunch. From cold and on the drive to lunch the temperature guage went up to below the half way mark and settled there (outside temp 39°). Two hours later started Stag after lunch and quite quickly temp settled just past the small mark on the gauge at the centre and slowly moved back to the centre mark for the rest of the journey. I was pleased. During the restoration I took the radiator to a radiator specialist to have it tested and it looked old and original so I was expecting to have to replace it. Iwas suprised when I collected it that it was fully cleaned and cored and painted. The mechanic said that after pressure testing it was 100% but when he pulled it apart it was only at 40% efficiency. I have the standard fan and shroud on my Stag and so the outcome of my experience is that the radiator is the key and should be made efficient in the first instance. The clean and recore cost $135 only.