My engine's going to be rebuilt (side seals going) and the temps have also been running a little high (1/2- 3/4), so instead of troubleshooting the temp problem, it was suggested that I just replace the radiator and thermistat and start off new altogether.

This seems to make sense to me, but if my overheating problem isn't fixed by this, then my new engine's at risk and I bought a new radiator/thermistat for nothing. I guess my question is, what other possible causes might there be for overheating? and how likely are these, compared to the radiator or thermistat? Or maybe just a new thermistat might fix it. How long does a radiator last anyway?

Just wondering if I'm wasting money or not.

Kevin

 

Kevin,

When I replaced my engine, the 6 month warrenty was void if I DIDN'T replace the radiator.

Other sources of over heating is ANY fluid leak. Mine kept having a problem until I noticed a dripping coming from the back of my Dynamic Air Chamber of all places. Fixed that, and my over heating problem went way. Leaks like this is easy to locate as there should be fluid staining where ever the leak is happening.

Over heating could also be from a bad water pump or cracked water jackets allowing exhaust to blow into the cooling system.

Anyone else know of other causes of over heating??

 

If the radiator is original to the car, then I would definately replace it. Odds are that it has not been maintained as per the FSM if you are not the original owner. Most people don't change their coolant every year. They aren't that much when you consider that it is probably 13years old I would probably try to get ahold of one of the fluidyne AL radiators. They bolt in stock, and have all of the fittings for the stock sensors. At least, get a new stock radiator and a Mazda OEM thermostat. The aftermarket ones are known for sticking closed, or not opening up all the way. That could also be a source for overheating. Might want to look into a new fan clutch as well, or at least check yours for proper operation per FSM.

 

Damn, only a 6 month warranty and you had to replace the radiator? Atkins Rotary gives you a 2 year warranty and you just have to have your radiator flow-tested by a radiator shop and follow the recommendations, if any.

So in answer to the question, just get your radiator tested by a radiator shop, they will let you know if it is bad or not. But I would only replace it with a Mazda radiator or better if it needs it, don't use some lesser aftermarket brand.