C1 running cold?

[Mike Tess]

My 1960 283/270 used to run hot, > 200 degrees acc'd to the temp gauge. Upon troubleshooting, I decided that the problem was the leaky radiator. After replacing it with a correct DeWitt's toptank model, the car now runs cold, acc'd to the temp gauge! Of course I was happy the car wasn't running hot anymore, but now the gauge barely gets to the first mark to the right of the 100 degree mark (I'm guessing that mark is about 120 degrees). I installed a new fail-safe 180 degree thermostat when doing the radiator job, and I know the engine is getting to that temp because the top hose is hot. The last time I ran the car before changing out the old radiator I let it idle a while in the garage, until the temp gauge almost reached 220. After shutting the car off, I could hear the coolant in the radiator starting to boil so I was pretty sure the temp reading was accurate. I can't verify the originality of the temp sender, but I recall from previous experience that the incorrect calibration senders would peg out the temp gauge. Radiator cap is the original 13# type. I don't know if the temp sender is bad, or the gauge is bad. Any ideas?

Thanks,

Mike Tess

[Terry D.]

Re: C1 running cold?

Mike

Easiest way to test gauge is with an IR gun at the top radiator hose. Let the car warm up and check it then. If you don't have access to an IR gun use a good digital meat thermometer, about $15 at a kitchen store, tape it to bottom of top radiator hose and let car warm up. A good tep sending unit is a Wells TU-5, sold at Auto-Zone.
Terry

[Terry D.]

Running Cold, Also

You should check the themostt to make sure it is not stuck open. Put it in boiling water to open it, then remoe it and make sure it closes.
Terry

[Ed Jennings]

Re: C1 running cold?

Assuming the car is actually operating at thermostate temp, the most likely causes of a false low reading are (a)poor connection at the sending unit, or (b)sending unit not properly grounded to the manifold (ie thread sealer interfering with electrical conducitivity).