C1 overheating revisited

[Don Izzo]

I am assuming that I am overheating B/C the temp gauge says so and the radiator pukes coolant out of the cap overflow ( I have filled the radiator to the top). I understand that the heat and pressure will displace some coolant after the car heats up but it pukes up a lot of coolant! I recently purchased a new (used) temp sender from Maryjo for my 60. When driving, The temp gauge will rise to about 180 and hold for a while before climbing up to 220-230. I had The car idle in the driveway for 20 min or more without going over the 180 mark. Is there a quick sure way I can test the sender to be certain it is correct for the C1? I am no electronic whiz kid so I dont own meters to test resistance at the sender etc. Should I purchase a remote temp gauge with sender and take the car out for a test ride? OR does this sound like I am actually overheating to you guys.

Don

Don

[Jack H.]

Re: C1 overheating revisited

(1) You MUST leave space in the radiator for coolant expansion. Most competent mechanics INTENTIONALLY overfill the cooling system to compensate for air trapped in the block/heater core that will 'burp' when the engine is first started and driven. It's natural for an overfilled cooling system to 'puke' coolant. With each sucessive engine shutdown, the amount of coolant expelled decreases and the system reaches it's own steady state equilibrium after 3-4 heat cycle events.

(2) Yes there is a way to test the temp sender, but you need to check resistance readings across the temp sender's dynamic range (100-240F) to really know what you've got and then, that's only half the story.... Not only does the sender need to be accurate, the dash gauge has to be accurate as well and there will be normal fluxuation due to voltage supply rail changes associated with the generator/voltage regulator (generator doesn't really 'kick in' until you're underway with the engine running up around 2000 RPM).

(3) MUCH has been written on this subject (my Corvette runs 'hot') and you can search the archieves for the gist of the matter.

(4) Do NOT think your car is running hot just because the dash gauge says so! Put science to work. You don't have to be a rocket scientist to take duct tape and affix an oven meat thermometer to the upper rad hose (safely out of reach of the fan) and go get a 'second opinion' as to what your actual engine coolant temperatue is! A better way is 'shoot' the rad hose with an IR gun thermometer, but these run about $100. If you don't have one (or can borrow one), the old oven meat thermometer and duct tape trick will get you close to the actual coolant temp (say within 10F)....

[Steve Westphal]

Re: C1 overheating revisited

Don, My '56 shows 220 degrees on the guage but runs a tad bit under 200 degrees with an IR gun which works for me. I am sure your mechanic has an IR gun. Go to him and have him shoot it and you will get an accurate read on actual temp. If your mechanic doesn't have an IR temp gun, better get a new 21st century mechanic.

[Doug Flaten]

Re: C1 overheating revisited

If after several cycles it is still puking coolant, you may want to check the radiator cap or replace it if old.