I have an 86 sport that seems to be running hot. The temp gauge is exactly in the middle. From what Ive heard, S4s tend to run around 1/4. The thing that boggles me is that, although my coolant level is fine, it does not bubble over. I dont know anything about the cars previous history so I dont know if the thermostat or temp gauge sensor have been replaced with non-factory units. Any help would be much appreciated.

 

Most do run at 1/4, but the stock gauge isn't too accurate, depending on the state of the cooling system that might be as good as you'll get and it may not be a problem. OEM thermostats are the best way to go, and of course make sure your fan clutch is still tight and all the ducting is on-the bottom sheild is very important for airflow

 

You could get an aftermarket temperature gauge, which wouldn't be a bad investments. However, I would suggest replacing your thermostat. It probably hasn't been replaced in 100,000 miles (or whatever's on your car) and they're not very expensive. Be sure to get a gasket to go with it. When I replaced mine the gasket was shot.

 

Would it be best just to order a thermostat from Mazda. I want to make sure its OEM instead of stant or something like that. As for the aftermarket temp guage, I work at a parts store, so Ill be getting one soon.

 

my temp gauge always said half an i didnt have any problems with it

 

Half isn't particually bad, but normal is about 1/4th. 1/2 suggests to me something is messed up/half broken/on its way out.

Like I said, replacing the thermostat is probably something that you should do anyways.