Temperature gauge reading 220

[John O.]

Hi All

I posted this question before about my 1962 250hp, fresh build 327 overheating, a couple weeks ago. You gave me good answers. I lowered the level in the expansion tank and I don't get the spewing out the overflow no more. There is no steam or gurgling so I don't believe the engine is overheating, but the Temperature gauge goes up to the 220 mark after it warms up and stays there during my driving. The gauge has been rebuilt and the sending unit on the intake is new.Is there any way to test the sending unit or should I just try replacing it to see if thats the problem? Also is there a way to test the gauge? I can't remember if there is a ground wire connected to the gauge but could that even be the problem?

Thanks very much.....John

[Harry Sadlock]

Re: Temperature gage reading 220

John, Anything can happen during a rebuild. My belief is that the sending unit and the gage act in unison. Saying that, they can be tuned together. Unfortunately it means taking the gage out of the car. There are a few shops that will perform the service. Joe Ray Parts is one I used for my 63. He has a WEB site.

What he does is heat the sending unit, then physically move the needle on the gage till it indicates the temperature of the unit. Then reinstall both back in the car.

Harry

[Don Izzo]

Re: Temperature gauge reading 220

John, I had the same problem with a NEW temp sender which was found to be not calibrated properly for the early gauges (C1 also). I remedied the problem by contacting Maryjo Rohner and buying an original temp sender. Also found that my car ran a bit hot after the engine rebuild until I reached about 2,000 miles then all settled down to normal temps.

Don

[Mark B.]

Re: Temperature gauge reading 220

John,

My 62 327-340 HP car does the same thing. I have a separate ground from the fuel sender and all of the wiring on the engine harness is new. However, when I drive it, it seems perfectly normal and doesn't overheat. I rebuilt the engine less than 6 months ago and thought the same as you about the tight clearances. I used a sending unit from Zip and installed it to find my gauge pegged at 220 degrees, also. However, I rebuilt the 283 in my 59 and used a Wells TU-5 sending unit from Auto Zone this time. The temp gauge reads dead on at 180 degrees. I plan on changing out the sending unit in the 62 with one from Auto Zone and hope that fixes the problem. You might try the same thing. Good luck.

[John H.]

Re: Temperature gauge reading 220

Shoot the radiator hose just above the thermostat housing with an I.R. gun and compare that reading vs. the gauge indication at the same time so you know what the gauge is really telling you; hardly any of them read correctly (too high), especially if the sending unit has been replaced.

[Jack W.]

Re: Temperature gauge reading 220

try a Wells TU-5 sender, you m-i-g-h-t have some success getting the sender and guage to provide you with advice that is close to what the IR gun tells you is the case. I tried two (senders) to get to one that worked . . .

[John O.]

Re: Temperature gauge reading 220

Thanks Mark

I think i'll go out now and buy a Wells TU-5 and try that. I have nothing to lose. Thanks to everyone else..If the new sending unit does not work and the gauge and sending unit need to be matched, what is that guys name and phone number and website that does that?
Thanks again to all..............John

[Greg S.]

Re: Temperature gauge reading 220

You mention a new rebuild. I have always heard that you should not use sealer on the temp sender as it may cause a false reading because of increased resistance. Maybe your original sender was reinstalled with sealer causing a falsly high reading after the rebuild.

[Gerard F.]

Re: Temperature gauge reading 220

John,

You could also try a meat thermometer taped to the radiator hose. It should read within 10 degrees of the gauge, but a little inconvenient to stop and read the gauge. At least you will know whether it's the engine or the gauge system.
Don't use the wife's, use a dedicated one (unless she doesn't know).

Jerry Fuccillo
#42179

[Les Jacobs]

Re: Temperature gauge reading 220

If you wife won't let you use the meat thermometer, you might try a visit to a Harbor Freight brick and mortar store (if you're lucky to live close enough). I picked up an IR thermometer(clock stopwatch etc) for about 9$ (on sale, but normal price was less than 20$). I originally got it for a kid, but tested it against my 100$ gun and found it surprisingly accurate. So the kid got a lollipop instead. Its not a laser type, and the acceptance angle is fairly broad, but if you can get the gun to within a few inches of the target, it works great. Les