Thermostat "A" control valve question
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Joined: Feb 2020
Posts: 6
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From: Saint-Petersburg, Russia
Thermostat "A" control valve question
Hey. You can find info about me and my car here. I have a question about vacuum control valve of "A" thermostat. According to the electric manual, 3-way solenoid "D" sends constant vacuum to keep the valve closed when ignition is on. According to the car manual (google photo translate):
So, there are my questions:
1) My thermostat cover valve doesn't hold vacuum (when I'm trying to suck air from it it goes free) - valve broken? (I was cheking on cold partly disassembled engine)
2) Black cover cap of valve has a little hole on it - for what?
3) Is that valve opened or closed by defaulf or when its broken?
4) Is it possible to remove top black cap to fix the valve if it is broken?
Conditions for closing the switching valve (thermostat cover ASSY)
a) Normal mode
e) Intake air temperature sensor is normal
f) Intake air temperature is 15 ℃ or more after starting the engine
g) Engine speed is 469rpm or more
b) A / C: OFF
c) Water temperature lower 108 ℃
d) Normal water temperature sensor
If any one of the above conditions is not satisfied, the switching valve (thermostat cover ASSY) opens and cooling water flows from the thermostat (A) to the radiator.
a) Normal mode
e) Intake air temperature sensor is normal
f) Intake air temperature is 15 ℃ or more after starting the engine
g) Engine speed is 469rpm or more
b) A / C: OFF
c) Water temperature lower 108 ℃
d) Normal water temperature sensor
If any one of the above conditions is not satisfied, the switching valve (thermostat cover ASSY) opens and cooling water flows from the thermostat (A) to the radiator.
So, there are my questions:
1) My thermostat cover valve doesn't hold vacuum (when I'm trying to suck air from it it goes free) - valve broken? (I was cheking on cold partly disassembled engine)
2) Black cover cap of valve has a little hole on it - for what?
3) Is that valve opened or closed by defaulf or when its broken?
4) Is it possible to remove top black cap to fix the valve if it is broken?
Joined: Mar 2001
Posts: 31,835
Likes: 3,232
From: https://www2.mazda.com/en/100th/
most of the ones i've seen/tested are bad, they don't hold vacuum, so it will always be closed. on the 20B FC, you can cut the thing off and add a radiator cap there, the engine will always be running on 2 thermostats, but this seems ok. and B we can't get the hot thermostat in the USA anyways.
the way the system works is that it normally runs off of a 92c thermostat, and when needed, it can open the valve and add the 82c thermostat. so when you're just loafing along at 1500rpm the engine actually warms up, and when you step on it, it stays cool.
the way the system works is that it normally runs off of a 92c thermostat, and when needed, it can open the valve and add the 82c thermostat. so when you're just loafing along at 1500rpm the engine actually warms up, and when you step on it, it stays cool.
Thread Starter
Junior Member
Joined: Feb 2020
Posts: 6
Likes: 1
From: Saint-Petersburg, Russia
most of the ones i've seen/tested are bad, they don't hold vacuum, so it will always be closed. on the 20B FC, you can cut the thing off and add a radiator cap there, the engine will always be running on 2 thermostats, but this seems ok. and B we can't get the hot thermostat in the USA anyways.
the way the system works is that it normally runs off of a 92c thermostat, and when needed, it can open the valve and add the 82c thermostat. so when you're just loafing along at 1500rpm the engine actually warms up, and when you step on it, it stays cool.
the way the system works is that it normally runs off of a 92c thermostat, and when needed, it can open the valve and add the 82c thermostat. so when you're just loafing along at 1500rpm the engine actually warms up, and when you step on it, it stays cool.
Joined: Mar 2001
Posts: 31,835
Likes: 3,232
From: https://www2.mazda.com/en/100th/
Thread Starter
Junior Member
Joined: Feb 2020
Posts: 6
Likes: 1
From: Saint-Petersburg, Russia
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