I have a Kenlowe fan on my 4.6 P38 & the instructions say that the fan should cut in when the temp gauge is between 1/2 and 3/4. I have noticed that when doing a steady 70ish on the motorway the temp gauge does start to climb up and the fan cuts in and drops the temp back down to 1/2 way or so.
Before I had the Kenlowe the gauge never moved over 1/2 and to be honest I don't really like it getting up towards 3/4 because we all know how sensitive the 4.6 & 4.0 are to overheating & slipped liners. Also, the engine book I have (How to Power Tune Rover V8 Engines for Road and Track) says that V8 should be run as cool as possible & that engines in P38s run extremely (too) hot for emissions purposes. Does bhp also drop as temperature increases?
I am surprised that the temp climbs so much at speed rather than at idle (in this weather it can idle without the fan cutting in), as I would have thought that sufficient cooling would have been provided by ram effect? The water pump is new & I removed & flushed the rad when I fitted the Kenlow. As I changed the pump and fan at the same time I can't be sure that the problem isn't something like water pump cavitation though. I am thinking of taking the Kenlowe off and replacing it with a new viscous coupling on my old fan to see what happens. IMHO I have found the Kenlowe to be a waste of time & the claims about MPG / performance increases are based on static fans (or those with seized viscous couplings), in fact I am concerened that the kenlowe is having a detrimental impact by having the engine running so hot.
Comments / suggestions?