The temp. gauge runs at the halfway mark when driving around town. Once up on the freeway, it goes up to the 3/4 mark and as high as between 3/4 and H. When I pull off the freeway it drops down to the 1/2 mark within a minute or so. It has never reached H under any driving conditions. It hasn't overheated, and when using a laser temp gauge, evrything seems within specs. Any suggestions?
What year/model/ehgine?
Moved to the Hudson sub-forum (from the "Club and Forum, Suggestions and Comments" sub-forum)
The car is a 51 Hornet with a 308 twin H and dual range hydramatic.
That seems to be what I have experienced with other 308's. The high end actually was about 200-205 degrees. Measured at the radiator with a direct reading thermometer.I suppose a resistor could be put in series to make the guage function in a lower segment. I was concerened about a 262 that the needle went to the top at traffic lights (with A/C on) until i took a reading.. just normal
I suppose you could drain the radiator a bit (to lower the coolant level), then remove the sender from the block. Then heat some water in a pan (maybe on a portable hotplate, near the car) with a cooking thermometer in it, and immerse the sender (still wired to the car) in the pan of water. Turn the car's ignition on, and see how the dash gauge compares to the thermometer in the water.
Or, you could simply buy a replacement heat sender and test it the same way without removing the old one in the block (disconnect the dash gauge wire from the car's sender, and hook it to the replacement being tested). Then, if the reading is reasonable, replace the old sender with the new. (If it's "unreasonable", you can shop around for another, and another -- till you've found one that's accurate. This method saves you from installing a progression of bad senders in the block, which is time-consuming.)
In this way you'll know exactly how accurate the sender is, regardless of what the dash gauge says. And if the dash gauge gives an incorrect reading, you will always know by how much it is "off".
I've always distrusted the method of checking coolant temperature at the radiator. The water might be a completely different temperature in the vicinity of the sender, in the block.
I once had a Volvo whose temp gauge "read" high. I think I checked the temperature at the radiator and concluded that the dash gauge itself was incorrect. I believed that right up to the day that the block cracked from the excess heat.
Wouldn't aiming the infared temp gauge at the the thermostat housing or elsewhere on the block give a more accurate reading of the actual trunning temp.?
Rob, I would believe that the small voltage regulator that is mounted between the temp gauge and the fuel gauge behind the instrument cluster may be failing. BUT, first check that the lower radiator hose is not collapsing. There is a two piece lower hose with a metal tube in between the rubber, or at least a "spring" inserted in a one piece hose to assist custom single hoses from being pulled inward & collapsing. Another issue could be a failing water pump( impeller is worn) or a pressure cap is not holding pressure (7lb). A laser gauge is usually spot on if aimed at the thermostat housing. Then take aim at the lower hose. It should be cooler.
Rob, If you determine that the gauge regulator is at fault, I have one I removed from a '51 that you can have- for the postage-. Terry
I'd like to take you up on your offer. Let me know how much you need and I'll send it your way ASAP.
Rob, e-mail me at snowshoe90@aol.com Terry
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