Hey guys I recently installed a new aluminum radiator and was really pleased with its cooling abilities. Last week I topped off the radiator drove 20 miles to the track, ran 5 strong passes, drove back home, and about a mile from my house after running 180 degs all the way home my temp shot up to 230 and then climbed to 150 for a few seconds and right back down to 220. I checked the radiator the next morning and I had lost over half a gallon of water. I check for leaks (none), watched videos of my runs (no white smoke), checked my oil (perfectly clean), checked the plugs (no sign of water), filled the radiator back up, drove around and the car stayed at 180 degs. Where is my radiator water going? My car is usually only driven to the track and back, so it is not a problem topping the radiator off before I drive back home from the track, but what is happening to my water?
Any ideas?
Thanks,
Danny

It sounds like your thermostat might be sticking now and then if the temps run up that high and fall back to 180 again. Is it maybe turning to steam when that hot and evaporating out of your overflow tank?

Water pump? That's the usual "mystery" water leak. It seeps out the bearing vent, and gets slung into a mist by the pulley so you never see it.

pressure test the system.
david

Could have been an air bubble(s)trapped in the system that got worked out. If it keeps up then I would do a pressure check.

If you run straight water you should check your water level more often - I've noticed that straight water seems to evaporate more readily than a mix.

An air bubble in the cooling system would not have waited five drag passes and almost 40 miles before manifesting itself.

What kind of a recovery tank do you have set up? It may be burping off water before the thermostat opens, and then not recovering it later.

You may have a hard to detect leak or fracture somewhere, radiator caps can be bad and still look good. Some head gaskets won't leak water when they are cold, but when they get hot they do. Most all shops have an analyzer that you run in place of the radiator cap to see if exhaust gasses are getting into the cooling system. You can also attatch an air fitting into each respective spark plug hole, pressurize, and look to see if the radiator starts bubbling up.

A half gallon lost in a 40 mile drive with 5 drag passes s a sereious loss. Something is way wrong, but is not yet obvious.

Thomas

I had a similar problem in a street car but it was the heater core leaking. Couldn't spot it at first brcause it was leaking under the carpet. Since yours is a drag car you probably don't have a heater core.

Thanks for the advice. It looks like I will have to do some detective work, LOL! I rechecked my plugs today and found one to have a slight greenish tint to the strap in cylinder #3. I am not running coolant other than Water Wetter, but these plugs were in the engine when I was running a coolant/water mix. Radiator water may be entering this cylinder. I have a typical catch can, yet no water has ever been deposited into it by the radiator. I am using a 20lb cap and am going to switch to a 16 lb, just to see if it makes a difference.
Thanks again,
Daniel