I had to replace a component on the car which, in the process, drained some coolant. I left the radiator cap atop the radiator that evening (hood up) with the intentions of topping off the system in the morning.

Next morning comes and I forget about the coolant, close the hood, and drive off. About 2 miles from home I see my temp rise to 235F, stop, and find what I did wrong. The radiator cap is still sitting next to the radiator, so naturally I fasten it on, and slowly drive home, keeping revs as low as possible. Water temp gauge never saw the high side of 240F, but I am wondering if the coolant sensor was actually reading the temperature of pressurized water vapor instead of coolant itself (water vapor or water/coolant vapor, under pressure, has a higher boiling point than 212F).

Not even cracking open the service manual, I top off the system and head out again............... temp rather rapidly rises to 230F, I realize I am not getting any heat, so I return home like before. Popped the hood, and even though the temp gauge was reading 230F, the cooling fans were not running. This time I bring the car back, break out the manual, find the location of the bleed fittings, and properly fill the system so there is not trapped air in it. Gave the car a thorough floggin, and temps are now running normal (195F-205F).

It's water under the bridge, but it's been bothering me: was the motor (especially the head) not getting coolant pushed through it during those times when air was trapped in the system? Would there have been any indications, by the way the car ran, that lack of coolant did some unseen damage? What about the water pump? I suppose it does not like to pump air, that is uses coolant to lubricate itself.

I ran the car hard, once I got my head on straight and properly filled the coolant. I had to add about 1 gallon, when all was said and done.......... but I also have an intercooler in the loop, so I don't know the total coolant capacity of the system - stock it's only about 2 gallons. Coolant temps now staying normal. But can there be unseen damage?

Thoughts/comments welcome (other than posting that I'm an idiot for forgetting to top off the system, and an idiot yet again for not consulting the manual to top off).

thanks,
Kleecker

 

You dun't need to trip.

 

if there was pressurized air in the system, wouldn't the water pump be pumping nothing (air?) for periods of time, or would it always be moving water because of how low it is situated?

 

Even following the procedure in the manual, you could still have air in the system and overheat 20 MILES LATER. This condition is particular to the S2000.

Usually when you have heat you're good, but I would check it again in the AM and top it off once again.

 

[quote name='kleecker' date='Mar 19 2007, 03:48 AM']I had to replace a component on the car which, in the process, drained some coolant.

 

It would be wise to keep an eye on the reservoir, mebbie keep the reservoir on the high side, that way as the system is burping the rest of the air out of the system, the reservoir won't run dry and re-introduce air back into the system.