Temperature control

[Cobra72]

Had the ECU/engine re-mapped on the dyno last week and found electronic water pump controller faulty so replaced with new Davies Craig lcd unit. Engine is running sweet, but temperature gauge rises above 100 degrees after about 20mins driving, water pump and thermo fan appear to kick in around 90' but engine still consistently above 100' (and as high as 120') in traffic. I also note the gauge can fluctuate rapidly between 95' & 120' (ie, 30secs to 1 minute)

1. Could this be a faulty thermostat?
2. If so, what thermostat should I replace it with (160' or 180') (302 Windsor)

Appreciate your thoughts.

[dhs.buckley]

Sound more like the gauge, temp sender or wiring, I would check the earths, the other way to check is buy a laser temp gauge and point it to the thermostat housing, heads, pipes and radiator to find the hot spot.

[renovationinnov]

cobra 72
I had a similar problem , I checked the gauge then the thermostat so last was the sender found out that I had fitted to much sealer to the threads & caused not enough earth
have you done any checks , try removing the thermostat & dropping it into boiling water to see how long it takes to open , or if it does , then try I different sender unit as these are the cheapest to replace, than the gauge

rob

[Cobra72]

Thanks gents.....will start with laser temp gauge to find hotspots and see if I can isolate problem. Both the dash gauge and new LCD water pump controller showing >100 so suspect gauge is ok. Will check the sensor though. Cheers.

[Trickycoupe]

I believe if you use the davies craig pump controller, you do not use a thermostat. The controller cycles coolant at a rate that allows correct warm up and cooling functions.

If the thermostat is fitted it will cause both a restriction and the controller to fight against it when trying to control coolant flow.