Do you guys have an extractor of any type in your hood? It worked absolute wonders for me both stopped and at speed- all in the cooper scooper thread.

get some good ducting in there, get the radiator cover up top, put an undertray in (OEM undertray not only protects the moving parts up front, it is also designed for, and is VERY effective at forcing more air through your radiator while moving) and make sure that both of your radiator fans are quality pieces and are working properly.

I don't know in the case of the Miata but in her car it was right behind the a/c buttons. I think your case is totally different because your blows air on the 3 & 4 positions. If I had to guess I would say your a/c is somehow disconnected when in those positions. It sure is weird.

Rob, I haven't been able to check what you asked (I'm waiting for a spare spal set).

I spoke to a local drifter who races a Sylvia and he told me his car used to overheat and the hood scoop he installed has made all the difference in the world. He even told me he's going to install the thermostat back because his temps are too low.

One thing I'm noticing is that temps (even with 1 fan working only) are low. The only thing we did was take all the coolant out and put some coolant in and bleed the system thoroughly. I'm starting to think that part of my problem was air in the system.

I can't try the a/c yet but as soon as I put in the new fan I'll try it and get back to you.

Many thanks again for your assistance :bigtu:

I love my flex-a-lite fans. They've made all the difference in the world. BTW, those are the 3rd set of fans I try in my car.

I've tuned my car for coolant temps. What I mean is that even my spark map has been tuned for the lowest coolant temps possible and not for the most hp.

In my particular case, the undertray would be as expensive (maybe more) as a hood scoop. I'd rather try the hood scoop but thanks for your input.

BTW, I found out I do have the radiator cover on :bang:

Ok Rob, I just went out and tested it. It overheats at speed (the Autometer gauge will climb and read 210) and it goes down to 195 when stopped and idling for 3 or 4 minutes. It won't go down any further.

I think I have to try the hood scoop.

Then I think it's airflow/pressure. You need to make sure that the mouth is sealed up good and install a belly pan- which will reduce the underhood pressure at speed.

Sorry to ask but; you don't think the hood scoop would have the same effect?

BTW, as usual many thanks for your help :bigtu:

I owe you

The hood EXTRACTOR would- it would reduce pressure at speed AND vent the heat under the hood whether the fans were running or not. That's what I've seen. But I wouldn't start messing with a hood until you've addressed the sealing of the mouth and the undertray - if only in the interest of time/money. You might find that those two things fix the problem. The undertray is a BIG component in effective cooling at speed. I ran a stock Miata w/o it and at 100mph the started to look like it was ballooning. That's a lot of pressure on the wrong side of the exchangers, not to mention a big boat anchor to drag.

Got it.

Thanks Rob.

Running without a thermostat will cause the coolant to cavitate under high rpms. I bet you'll see steadier temps if you atleast run a gutted thermostat.

O RLY?

Define cavitation, then after you've looked it up you'll know why what you said doesn't make sense.

(hint, it has to do with speed of impellers, not water)

Edit: Granted, I'm certainly not saying that removing the thermostat is a good idea. I don't think it is. I just highly doubt the water pump is spinning fast enough to cause cavitation.

Hey, I could be wrong too.

A dentist can fix that cavitation.

So Rafa should just see his dentist and it should work itself out? :laugh:

I guess I should :laugh:

I'm not really sure what you don't understand about my statement but it sounds like the OP is having trouble with high temps at higher rpms and not at idle when the water pump is spinning relatively slowly. He could try gutting a $7 thermostat... or not. I'm not sure if it'll help, just trying to knock out the simple stuff first. I'm sure sealing every seam in the nose or getting a new hood/fabricating a scoop is easier though.

I would never run without a thermostat. A properly functioning thermostat will not cause a car to overheat.

An unsealed bumper mouth will contribute to overheating much more quickly. The sealing helps to keep the hot air from circling back around through the radiator again and again. It only allows cooler air from out in front of the car to enter the radiator and not hot air from under the car. The sealing also promotes a lower pressure area behind the radiator than in front of it which aids in airflow through the radiator when moving. Mazda didn't spend all of the money and time designing, building, and installing all of that plastic for no reason. They are far too cheap than to waste resources on something that wasn't necessary.

Sorry man; I think I did not make it very clear. I'm facing high temps issues not at higher rpms but at higher speeds and only when I have the a/c on. If I turn the a/c off temps won't go past 180 degrees at speed.

Thanks for your input anyways.

Shooter, you know I like your advice and usually follow it but in this case these past 4 months have been hassle free when it comes to coolant temps without a thermostat. Care to expand on the reasons for not running without a thermostat?

I hear what you say about sealing the front bumper of the car but I've read some threads about it and I'm not sure I could do a good job and I think the hood scoop will be easier to do (at least down here).

Thermostat keeps the water from passing through the radiator too quickly. Better cooling.