Well add me to the list.
I tracked my car for 2 years and the guage never went above 50%.
(ask anyone who has ever seen me run, and they will agree that it is hard to find anyone who pushes the NSX harder than I do)
Then all of a sudden one day at the gas station, I left it idle for 2 minutes and it went into the red!
A few weeks later I did a 2.0 mile road course in 90+ degrees and mine for the first time was creeping up, but only after back to back sessions at the end of the day. Steves went into the red, and Seans was creeping up a bit more than mine.
It was 100% fine for street driving, as long as no idling.
So yesterday I let it idle in the driveway and it went into the red, and blew steam out of the dump tube (Dali tank).
Enough was enough. For 2 years now I have been helping Steve diagnose is overheating issues. I have said to do just about everything mentioned in this thread but forgot the oil-cooler idea.
Ok back to mine.....
I checked for air (We did this a thousand times on Steves car, but never on mine. I had no air pressure at all!!!!!! Not even a drop of fluid came out of the front 2 spots!!!!! (skipped the rear at this time) I looked in the tank, and it was about 2/5th full. I got pissed and filled it to the top. I then started it up for 10 sec, and burped the front 2. I got some pressure but no fluid. I started it again for 10 sec, and now got air and fluid from the rubber one, but only air from the white one. I repeated about 2 more times and got all air out and good fluid pressure from all 4 spots. I looked at the tank, and it only dropped down to about 3/4. I then started it up and let it idle for 30 minutes. Wallah!!!!! Guage never moved from 1 tick below 50% and the fans went on/off/on/off/on/off etc etc. EXACTLY what it should do.
Conclusion. I think even a few "cups" low on coolant, makes the difference of running correct, and completely overheating, thus blowing the dump tube, adding air into the system from lower coolant levels, and higher engine temps, thus possible slight gasket leakage etc etc. This is just a downward spiral.
I am going to try to run a higher level of fluid, run the dump tube to a catch can that has the end of the hose submerged to reduce backwards air introduction, and run a higher pressure tank cap (22) and possibly a drilled thermostat, or absence of one. I am also going to add an oil cooler, and look into a higher volume oil pan.
I used to think that the thermostat was not allowing the hot fluid to circulate until it was too late, but now it looks as if the low volume (for some reason) was doing a combination of the following.
1) low volume= higher fluid temp
2) higher fluid temp= 16lb tank cap blowing steam
3) cap blowing steam= reduced volume even more and possibly introduced air
into the tank/system
4) air in system caused poor circulation, which raised temps even more, thus
blowing more steam, and possibly having the gaskets start to leak some air
into the fluid.
on and on..........
I am going to try the higher volume of coolant at the next event, followed immediately (if still an issue) the 22lb cap, low temp or no themostat, and fan on a toggle switch.
If that does not work, then I will try the distilled H20 and Redline Wetter.
Lastly a FAL fan (toggled) with a ducted shroud and hood.
I am also hooking the engine compartment fan to a toggle as well.
