Landseer

Have you got viscous fan on that car? If so, refilling the silicone fluid can help. Sometimes people lay them down and they drain out. Makes a big difference in traffic when it works.

vze2jshn

Thanks, did silicone routine on fan prior to IR gun checks with no change in temp gauge readings.

jpitman2

My temp gauge jumps up nearly 1/8" when sidelights go on also. I put it down to a bad contact somewhere (probably an earth), or the instrument voltage regulator is off. Lights off, the gauge makes sense - cruising at a steady 60mph,cool weather, reads very close to centre scale. Using electric fans, in stop start driving, it cycles up to just under second mark , and back to just above centre. If your gauge doesnt correlate with reality, first suspect would be electrical connections. Speaking of which , something above prompts me to clean the 14 pin connector up front and see if that improves anything.
jp 83 Euro S AT 52k

vze2jshn

Problem solved? recently replaced pod back lights (2), temp gauge light and alternator light with wedge LEDS. Had to take out alternator gauge LED and reinstall old bulb because LED did not let or pull enough current to excite alternator at start- up. To the temp. gauge point-- since installing LED wedge bulb in Temp. gauge light socket, temp. gauge is now behaving normally, to my great relief. Carl Fausett had suggested that the new wiring harness had less impedance and therefore temp. gauge was reading inaccurately too high and that I either ignore it (tough to do) or experiment with inserting a resistor in the circuit to get gauge behaving properly. It seems the LED bulb has served that purpose. I have been looking at WSM wiring diagrams and can not determine if the temp. gauge bulb could affect the needle gauge circuit in such a manner. Any comments are greatly appreciated.

karl ruiter

Having the same problem on my '79. Just finished a build and install of a fresh motor and huge electrical clean up and I'm seeing the temp gauge reading quite high. My sense is that the gauge is simply wrong, because then electrical fan does not come on until the gauge is near red and then it does cool down a bit. But it is quite unnerving and I want to fix it, and I suspect it could also be the thermostat keeping the engine hotter than the radiator. It is absolutly not that the two temp wires on the sensor are switched. I have tried swapping them and that makes the temp light come on and the gauge read dead cold in all situations. I have a fresh 12 pin connectors, so I don't think it is that. A few questions:
-Does anybody know what sensor resistance should look like v.s. gauge position? If I had a number for, say the 2nd white line, I could throw that resistance in where the sensor is and see if the gauge was working right.
-Does anybody have a plot for what the sensor should do v.s. temp? That would allow me the check the sensor. At least at room temp.
-What IR gun is everyone using? I seem them for as little as $20, and would be more than happy to invest that to be sure my motor is acutally running at the right temp, but I suspect you have to pay more to get something useful. Any tips would be great.

fraggle

Head to towerhobbies.com. I use the thumb size temp gun designed for tuning nitro RC engines. I thin it was $25 or less. May not be as fancy, but it fits in the glovebox and stays there.