Overheating on track

ivan · Postby **ivan** » Sat Dec 27, 2008 7:02 pm

Thanks for the replies. Stan, the car is a NA6, and I do tend to keep the revs up quite high...and temp was around 26 i think. The thing that bugs me is that there was another MX5, practically identical to mine and there was no heating issues. He didnt keep the revs up as high as I did though (off track...no pun intended, but when I turn into the fish hook at Wakefield I blip it into 2nd and it goes to around 6500, am I being a bit too harsh on a stock car??)

The car didnt have any symptons of over heating other than the needle moving up.

I've just flushed the radiator and it didnt seem like anything was blocking it. The number plate does hand done a little, but not too much. I'll take it off next time i go out on track and see if it makes any diff.

The radiator only has one fan covering half of it..is that correct? The fan does work though.

How do I know if there is any thing wrong with the thermostat?

Also, what is the point of changing the radiator cap (it looks like the original one)? It didnt release any coolant when the gauge went high...

fattima · Postby **fattima** » Sat Dec 27, 2008 10:15 pm

ivan wrote:Thanks for the replies. Stan, the car is a NA6, and I do tend to keep the revs up quite high...and temp was around 26 i think. The thing that bugs me is that there was another MX5, practically identical to mine and there was no heating issues. He didnt keep the revs up as high as I did though (off track...no pun intended, but when I turn into the fish hook at Wakefield I blip it into 2nd and it goes to around 6500, am I being a bit too harsh on a stock car??)

I run my NA6 (car is stock) on the track and I have no over heating problems. At the Winton six hour it was on the track for an hour on a day that was about 28-30 degrees. The car spends a lot of time over 6500. Before taking my car on the tack I fitted a new radiator (Koyo brand from an auto), new thermostat (from Mazda), new hoses and rad cap. I run Redline water wetter and de mineralised water.

ivan wrote:The radiator only has one fan covering half of it..is that correct?

For a non aircon car it is, my car only has one fan.

ivan wrote:How do I know if there is any thing wrong with the thermostat?

http://www.focushacks.com/printable.php?modid=60

ivan wrote:Also, what is the point of changing the radiator cap (it looks like the original one)? It didnt release any coolant when the gauge went high...

If it is not holding pressure the temp will go up. The pressure in the cooling system helps prevent the coolant from boiling.

It is cheap and easy to replace the thermostat and radiator cap so probably worth doing.

CT · Postby CT » Sun Dec 28, 2008 8:04 am

ivan wrote:, but when I turn into the fish hook at Wakefield I blip it into 2nd and it goes to around 6500, am I being a bit too harsh on a stock car??)

Can I suggest enhancing your driving by using the brakes to stop you first and perhaps try using 3rd in the fish-hook instead. I know the NA6s are pretty gutless down low but reving the sh*t out of them isn't always ideal either. As for cooling, even if your radiator runs clean water, it can be half clogged. Either, remove it and get it re-cored by a pro or replace with a 1.8 NA auto one which uses a heavier core. Then, replace your thermostat with a Mazda one, replace all hoses with new rubber (not that silicone sh*t) ones, and replace with a quality coolant, ie Radicool from Castrol has always been a good one. make sure your fan works and stick on a new rad cap.

Then if your car still overheats, ensure the airflow is not blocked by grills or number plates and fit a decent oil cooler with a thermostat. Contrary to much knowledge on this forum, the MX5 really benefits from an extra oil cooler. All of my track cars have always run oil coolers - even the na ones.

Of course, constant overheating can also suggest a head gasket issue if it continues to persist.