Hi, I'm changing the thermostat in my 1.9 watercooled 86 van. When i took the original out the dome end was pointing up towards the bleed valve. But I have seen several illustrations now and it is the spring side which is pointing up towards the bleed valve. I'm not sure now which way round to put it back.
The fault i'm trying to fix is that she started over heating. She would reach temp as normal but would then carry on warming up and the light would start flashing. The fan is OK.
Any advice gratefully received.
Cheers.
Kiteboy7.
Thermostat, which way round?
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kevtherev
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Re: Thermostat, which way round?
hello and welcome to the forum..
The secret of the thermostat lies in the small cylinder located on the engine-side of the device. This cylinder is filled with a wax that begins to melt at around 180 F (different thermostats open at different temperatures, but 180 F is a common one). A rod connected to the valve presses into this wax. When the wax melts, it expands significantly, pushing the rod out of the cylinder and opening the valve... rather like a thermometer.
So the cylinder on the stat has to be on the Engine or hot side.
does that help?
The secret of the thermostat lies in the small cylinder located on the engine-side of the device. This cylinder is filled with a wax that begins to melt at around 180 F (different thermostats open at different temperatures, but 180 F is a common one). A rod connected to the valve presses into this wax. When the wax melts, it expands significantly, pushing the rod out of the cylinder and opening the valve... rather like a thermometer.
So the cylinder on the stat has to be on the Engine or hot side.
does that help?
AGG 2.0L 8V. (Golf GTi MkIII)
Re: Thermostat, which way round?
Cheers Kevtherev, thanks for the welcome,
Just to clarify, the bit with the wax in is the bit surrounded by the spring?
I though it was done with bimetalic properties of the spring.
Thanks,
Kiteboy7
Just to clarify, the bit with the wax in is the bit surrounded by the spring?
I though it was done with bimetalic properties of the spring.
Thanks,
Kiteboy7
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kevtherev
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- 80-90 Mem No: 2264
- Location: Country estate Wolverhampton Actually
Re: Thermostat, which way round?
Whether it''s a wax cylinder type with a spring or thermo spring it will always be on the engine side.
AGG 2.0L 8V. (Golf GTi MkIII)
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kevtherev
- Registered user
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- Joined: 23 Oct 2005, 20:13
- 80-90 Mem No: 2264
- Location: Country estate Wolverhampton Actually
Re: Thermostat, which way round?
You will also notice a disc at the bottom, when open this directs the coolant to flow to the big by pass (metal tube) which terminates at the pump, this then circulates the cooler coolant to the cylinders.
If it were to be put in the wrong way the stat would eventualy open but the flow of cooler water would close it much to soon and the engine would eventualy over heat
If it were to be put in the wrong way the stat would eventualy open but the flow of cooler water would close it much to soon and the engine would eventualy over heat
AGG 2.0L 8V. (Golf GTi MkIII)
Re: Thermostat, which way round?
Thank you Kevtherev,
I have a bit more confidence now that it will go backtogether correctly. Hopefully it is the cause of the problem. I tested the old one, there was some movement but only after the water was boiling.
I have a bit more confidence now that it will go backtogether correctly. Hopefully it is the cause of the problem. I tested the old one, there was some movement but only after the water was boiling.