QuestionI Just had the water pump, thermostat, timing belt, valve cover gasket, radiator cap, cam seal, and crankshaft seal replaced because the car started over heating. It would steam from the front. After all of those things were replaced, 5 days and 300 miles later it starting to do the same thing, including the over heating and steaming from the front. What do I do?
AnswerCooling issues are either;
air flow related or fluid flow related.
Air Flow:
Check inside the mouth (grille) make sure there are no obstructions. Miatas have a tendancy to suck up trash like grocery bags. A blockage of air will cause an overheat.
Next turn your AC on and check that both fans are spinning. Make sure you can feel a force of air coming from each one. A 12v motor can fail yet still spin with no force. If both fans are not spinning with the AC on then the one not spinning or spinning without power is the blame. You can cross check the fans by unplugging the connections and jumping 12v to each fan directly to see if it is in fact dead or alive. On occasion I have seen fan blade hubs fail which means the motor spins but the fan blade doesn't or at least can't spin with force due to slippage where they mate.
Fluid Flow:
Water Pump, check
Thermostat, check
Hoses, check
Top tank of the radiator, check
Ignition Timing, check (be sure your not to far advanced for your altitude)
Heater hoses, check
A fluid pressure test will let you know if you have any leaks, top tanks are know to fail as they get older from stress. The top tank is plastic, this is not a cheap design rather a fuse of sorts. So if you find the radiator to have a leak replace it with a good plastic tank one and not an all metal one. Logic being, if it ever overheats due to a belt, or a bag or whatever. Better to have the radiator top tank split open like a fuse then to have a blown cylinder head gasket or worse, right? That's what you get with cheap all metal radiators.
