i am thinking of puting one in. i know it will make me run rich but is it worth it? to make the engine run cooler? i put it in my 87 na and the needle barly went above the bottom slash but it gave me a sence of security. and how will it affect performance? oh btw i have a 90 t2

 

why do you want to do this???

A rotary does not usually benifit from cooler engine temps like a piston engine does.

 

right now my normal operating temp. is just a tiny bit above the middle and i get scared lookin at the gauge. is that normal? i know the gauges changes slightly between the s4 and s5

 

if the engine is running hot, why don't you fix the car, instead of masking the problem with a lower temp thermostat?

 

i think its running normal, but to my eyes it kinda looks like the slash is above the middle...tiny bit

 

mine is just over half way

 

ok so it is normal then....phew

 

wowo! over hlaf way? what climate do you guys live in? mine almost never even reaches halfway, only tiime it did i had air in the rad.

 

That is because you have a S4, where the normal operating temp is 1/3-1/4 of the way up the gauge. On a S5 normal is located right at 1/2way.

 

As stated above it's normal, however would like to add. If you ever do experience an overheating condition, a lower thermosat will only open sooner, not control the high coolant temps. As Icemark stated you'll need to fix the problem.
Bottom line, keep the Mazda thermostat.

 

Just for future reference, swapping in a colder thermostat will not even mask an overheating problem, let alone fix it. Overheating is caused by either increasing the engine's output beyond the capacity of the cooling system or by some problem that causes the cooling system heat removal capacity to be reduced (low air or water flow for example). It's safe to assume that the thermostat will be fully open when the engine gets hotter than normal (unless it has failed and is actually the causing the problem), so simply opening it earlier will not stop that fact that the engine is still producing heat faster than the cooling system can remove it.

 

The most common temp creep cause is a fan clutch that's starting to wear out.

The fan clutch uses a silicon oil viscous fluid in two chambers inside.
The Bi-metal strip on the front bends outward as it warms and opens the valve from the reservoir side to the clutch side.
Centripetal force provides the pumping action to move the fluid.
After 100,000 miles the bearing seals wear, and the bearing lube weakens the clutch fluid's grip.
Both the S4 & S5 clutch freewheel when cold.
The s4 clutch increases it's bite gradually with temperature rise.
The s5 clutch & some aftermarket S4's are more on-off. (It just coasts until is gets warm)
Once they are warm, the fan speed goes up with engine speed to about 4000 RPM.
As the engine revs higher the fan stays at ~4K.
If your warmed up fan only revs up to ~2500 RPM, it's bad.