My ED 4L GLi on duel fuel (bought it about 2 months ago) seemed not to register on the original temp gauge( poverty-pack instrument cluster )...then I changed to sports instrument cluster and still hardly registers on the temp gauge. Have checked and renewed temp sender on thermostat-housing & checked current continuity to dash OK, replaced the standard thermostat with the advised (shorter) type thermo for gas...still no joy. At cold start-up the gauge reads below zero (and the red water-temp light is on)....then after running for about 5-10 minutes the needle just moves up above zero (and the red jewel goes out). Needle never wants to move up to even quarter. COULD THIS HAVE ANYTHING TO DO WITH THE GAS-SPEC THERMOSTAT OR THE FACT THAT THERE'S A HOSE(COMING OFF THE THERMO-HOUSING) GOING OFF TO THE GAS MIXER?? Anyone with gas falcons seen a difference in the water temp readings compared to pre gas installation? or maybe it's just an earth-leak in the wiring (which I suppose would be pretty hard to trace!!). Any suggestions greatly appreciated. Thanks....Steve.

If the thermostat is allowing too much flow and the system isn't getting up to temp because of this, a test could be to run the motor in a manner that will get it to warm up regardless. Doing this may tell you something. But maybe you have another problem and this test could exascerbate it. I don't know. If the guage isn't reading properly then you have to tread carefully.