3rd Generation Specific (1993-2002) 1993-2002 Discussion including performance modifications and Technical Support Sections.
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Old Aug 15, 2007 | 07:42 AM
  #1  
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no thermostat

is it a good or bad idea to run the car without a thermostat??

94 single turbo.
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Old Aug 15, 2007 | 07:52 AM
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Thumbs down Bad idea!

Bad!
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Old Aug 15, 2007 | 08:19 AM
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I'm not 100% certain on why it is bad but I believe it has something to do with the actual flow of coolant being too fast to cool off properly.
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Old Aug 15, 2007 | 08:46 AM
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1. Coolant will cool faster with faster flow (less boundary layer => better heat transfer).
2. With faster flow, coolant will be at a more constant temp throughout the system (cooler in the engine, warmer in the radiator => more heat transfer, plus less thermal gradient in the engine => parts expand more equally).

So, faster flow is not the problem. The problem is that the engine will in most cases, w/o a thermostat, never reach proper operating temperature, and will run inefficiently, plus controls that transition after the engine has warmed up may not be activated.

The old saw that slower flow => better cooling comes from needing (in some cases) a restrictor at the engine outlet so that the WP causes a pressure build-up in the block, helping to prevent localized boiling and the resultant poor heat transfer at the boiling points. This localized boiling is sometimes unstable, in that once it starts, if it is bad enough, cooling efficiency can be degraded to the point that overheating will result, and coolant will be lost.
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Old Aug 15, 2007 | 09:44 AM
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Okay I Guess I Will Put One In Then.

But My Water Temp During Drving Is Around 92-100 Celcius..
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Old Aug 15, 2007 | 10:01 AM
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A rotary will actually run hot without the thermostat. The way the thermostat in the RX-7 is designed is that when the engine warms ups and the thermostat opens, the plunger on the bottom of the thermostat covers the bypass hole in the water pump. If you have no thermostat, then the bypass hole is always open and a lot of the coolant will flow through the bypass hole and never go through the radiator to be cooled.
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Old Aug 15, 2007 | 10:05 AM
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great explanation thanks..

im gonna trow on in asap..

i drove with out one for about 3 weeks and my temps were always around 92-100 celcius do u think i caused any damage?
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Old Aug 15, 2007 | 10:10 AM
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You probably didn't do any damage. Most of the time damage occurs from a rapid rise in temperature such as happens when you break a hose or belt. The rapid rise causes the aluminum rotor housings to expand so fast that they get crushed between the irons.
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Old Aug 15, 2007 | 10:15 AM
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okay so i should be good then.....

idk if this would have anything to do with it but last night my car cranked 4 times before starting up when before it only took 2 cranks??

took 4 cranks this mourning too??
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Old Aug 15, 2007 | 10:17 AM
  #10  
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Well, I guess if it gets harder and harder to start and you start noticing steam in the exhaust and you're losing coolant, then you might have done some damage.
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Old Aug 15, 2007 | 10:23 AM
  #11  
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im not loosing coolant.

it only steams a little bit wen its wet out ( condensation)

exhaust does not smell like candy so i think i should be fine.
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Old Aug 15, 2007 | 10:44 AM
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You should be fine then.
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Old Aug 15, 2007 | 03:52 PM
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Just Bought The Thermalstat

Will Install It Tonight.
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Old Aug 15, 2007 | 07:22 PM
  #14  
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good read for a race car....prob not a good idea for a street car

http://www.mazdamotorsports.com/weba...ubject=cooling
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Old Aug 15, 2007 | 10:43 PM
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Originally Posted by revhardallday
Just Bought The Thermalstat

Will Install It Tonight.
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