Ok I have an 86 na when driving down the Highway stays about a quarter on the temp gauge but when i'm driving in like a 45 zone heats up to about 3\4 on the gauge has a new thermastat new caps and the heater works amazing what could be the problem?

 

Check the clutch on your engine fan.

 

It spins freely warm and cold all the way around I was thinking it was bad and can't find one anywhere

 

Have you tried posting a WTB ad in the classifieds on here? Plenty of those around...

 

It's available from your local Mazda dealership or from Mazdatrix.
Mazdatrix - Pulleys, Fan Clutches, Thermostats, Belts

 

The fan should have some resistance to it when the engine is cold.NOT ON..you can test it that way.If it feels like it will spin it freely then it is shot,or going to go.
Funny that you say that you can't find one anywhere but haven't posted any AD looking for one.

 

overheating at speed? is your undertray on?

 

for some reason I thought it just over heated at 45 and above, if you don't have an undertray you should but that's probably not it lol

 

Changed the fan clutch problem solved thanks for the inout guys tons of help

 

from not finding one to fixed in a day.. guess you weren't looking very hard.

 

I forgot about mazda nissan heaven in fort worth lol

 

Shhh!