<!--[if gte mso 9]><xml> <o:OfficeDocumentSettings> <o:AllowPNG/> </o:OfficeDocumentSettings> </xml><![endif]--> Dave,
It is with some relief that I came across your thread today as I have been trying to get my head around an over-cooling phenomenon. I just got my build on the road in time for July heat. A Gardner Douglas T70 with GM LS6 and a Davies Craig water pump and controller.
In a half hour traffic jam at 35C ambient, the dash gauge indicated the continuous cycling of block temperature increasing to the DC fan switching point, fans coming on and temperature reducing until fans turned off. The indicated range was from 75C to 90C. However, as soon as the jam cleared and air passed through the rad, the gauge temperature fell to 45 / 50C, matched on the DC controller.
I too contacted DC to be advised to fit a stat with two 5mm dia. holes but I have formed the view that my pump (150 litres per min) just flows too much even at 6 volts pulsing 10 seconds on / 10 off. I have been considering fitting a smaller DC pump but I notice that you use the 115 litre version, so maybe this would not be the answer.
Following your data gathering last year, do you have anything to add that may help understand what the heck is going on?
Hi John, I showed that the temperature maintained at the thermostatic bypass valve near the radiator matched the stated opening temperature of the valve, I just moved on, and I think that the operating temperature of the engine before I put the DC in must have been a lot higher than indicated. I've forgotten the details, but I will check and let you know.