Post by thread:Fwd: [TECH] Mazda Miata overheats update2

On Jun 17, 2011, at 4:30 PM, YES NOPE9 wrote: circa 1990 same engine , replaced water pump 5 years ago. gradually overheats on long drive. no coolant is missing. fan belt is quiet ... does not appear to be slipping. turning on interior heater with fan brings temp down. flow diagram seems to indicate that heater bypasses thermostat. radiator is brand new ( 6 months ) PROGRESS..... I have installed a new thermostat. The old one seemed to have lost the ability to warm the car up rapidly. On Saturday 2011m06d18 I drove the Miata on a longish ( 30 minute ) uphill drive. The temperature briefly went above normal position ( 50% ) during one climb ( to 60% ) and then returned to normal. The Miata seems to warm up faster ( much like it did when it was new). I had felt that maybe the thermostat was not closing properly which had caused the slower warmup to operating temperature. 2011m06d19 So I do not think the problem is corrected. I will now look at the water pump. I will also flush the coolant system. MISC..... For those wondering about the engine being 5% shorter ....... See this video ............ http://www.youtube.com/watch?v=Rap5NohGd7w Also note I have used an alligator cable in place of the proper temperature switch for the radiator fan. ( Yes the fan is spinning ) I am looking for a generic temperature switch.. 99guspuppet