I had no problems whatsoever with overheating. Now, occasionally, after dropping in a fresh mazda rebuild, new water pump, thermostat, and collant level sensor, i do...

pertinnent mods:

ast removed
fluidyne al. radiator
coolant fan mod.


Help....

 

Make sure and purge all the air out of the cooling system

 

Do the radiator, and maybe consider the Evans coolant. My car used to have a dancing temp gauge, but after putting on a Fluidyne, and Evans coolant it ran fine. Evans probably isnt necessary, but I dont really know since I put it in with my radiator install, so I dont know for sure.

 

Make sure both fans work. I had 1 which burnt out.

 

I suspect air in coolant, epecially bc you removed AST. AST is designed for a reason. I don't think it's wise to get rid of it. Those aluminum ones don't have the stock shape which is supposed to help trapping air somehow according to my rotary specialist. The Japanese spec AST is made of a durable plastic and that would be the best replacement.

If it's not air trapped inside and you're overheating only when your are in traffic, I would look at fan operations. The fan relays/thermoswitch maybe bad, not turning fans on or full speed when needed.

Did you put in a new thermostat? That's another place I would look.

Good luck and get this fixed soon before you bust that engine.

 

the ast, fluidyne rad, and fan mod (both working) were done before I bought the car and before putting the engine in.......