1959VetteJan

Ok, more issues with my recent acquisition. The temp gauges rises steadily and makes it all the way to the 220 line. It stays there, independent of how I drive the car. The probe is new and does seem to work, since the temp gauge starts from the 100 line when cold and makes it steadily up to 220 when hot. Is this a water pump issue? The radiator is full of fluid. The upper radiator hose is very hot and so is the upper heater connection. The lower hose is not quite as hot, perhaps only warm and so is the lower heater hose.

Thanks for any insights you can provide.

Jan

62Jeff

First, confirm the car is actually running at 220 with an IR gun on the upper radiator hose.

Most temp sending units are calibrated wrong these days.

Frankie the Fink

ABSOLUTELY ! The replacement temp senders are notoriously wrong in 95%+ cases. As much as 20* or more off. Get an IR gun (Harbor Freight has some cheap versions) and point it at the thermostat housing with the car warmed up and compare it to the dash gauge before panicking. If you aren't "puking" water out the overflow from the expansion tank your gauge is probably reading incorrectly.

1959VetteJan

Thanks for the help. It did release excess water but then again i added quite a bit of fluid yesterday to address the perceived overheating issue. I had not done this previously.

Jan

vette61

If in fact your gauge is reading incorrectly after checking the hose at the thermostat with an IR gun you can add a resistor in line with the temp sender wire (can't recall what ohm size). This will bring the gauge within +/- 5 deg of the actual temperature. Somewhere in the archives it talks about dong this which I did on my 61.

1959VetteJan

Closure! Your were all correct. It is the temp sender. The heat gun shows between 125-180 degrees tops.

Thanks again for your help. One down.

Jan

1959VetteJan

Hi,

Just wanted to follow up and report that my vette appears to heat up to 178 after having been driven for 30 minutes. My second reading after another test drive was closer to 190F. This still looks high to me. What do you think? I used a heat gun pointed at the
thermostat housing to check the temp.

Thanks folks,

Jan

62Jeff

Sounds perfect, don't mess with it.

OldKarz

I think I would not mess nor worry about it!

Dan Hampton

How old is the radiator and when was it last flushed out? Twenty year old, unconditioned units like the one you have can be running 60% efficient.

John S 1961

I had this same issue, It would climb-stabilize, stop in traffic, climb more-stabilize, I pulled the therm housing and the therm was stuck (just a small amount of corrosion stuck it), I cleaned it up, added some bleed holes around the periphery. It runs good now, about 190 on a 85 degree day. These cars are under cooled

1959VetteJan

Thanks everyone. I would be lost without you!!!

Jan

1959VetteJan

The latest temp reading was closer to 210 after 15 minutes of driving with outside temps around 55. Still normal?

Thanks,

Jan

Frankie the Fink

My original 283ci never gets over 190* even in Orlando summer heat.

jim lockwood

Looks high to me. My '60, equipped with a 160* thermostat and an aluminum DeWitt radiator would struggle to maintain a temp as high as 160 on a 55* day.

Jim

Geralds57

That's not normal on a cool day. Is it actually steaming or making a whining noise when you shut it off? Is it running rough at that temp? If so, two main things to look at would be if the timing is way off or the carb is running too lean. Both will make it run hotter. Your distributor advance may not be working also. Check the weights and springs on top of the distributor shaft. Look for stuck weights and broken springs. Pull on them, see if they are free and then swing back.

1959VetteJan

Well, turns out that the radiator cap was not fully closed. I wonder if that played a role in this. I have been driving it today for an hour with 75 f outside temperature. When I came back home the temp gun reading was 195, this time with the cap fully closed. Still a bit high?

Thanks,

Jan

BobT59

Still seems high to me. My 59 was always a hot engine ever since I bought it 48 years ago.... radiator flushes helped alittle but as time went on, it got almost almost undriveable... even replaced the core once but that didn't solve the problem.

Finally, 2 years ago I broke down and spent the $$$ for a Dewitts aluminum.... gave the car and me a new lease on life... I don't have a thermostat in it right now but it runs at alittle over 140 on a 60 degree day.... during the summer, it will hit 180 on a 85-90 degree day but the electric fan brings it down another 10-15 degrees, even in traffic.

One of the best investments I ever made....