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Discussion Starter #1 (Edited)
Ok surprise me !

EB1 3.9 Fairmont auto

Why is it that with a lower temperature thermostat, my car never reached past a quarter on the gauge if it got that high at all?
Now I have gone to the normal one, 92 degrees I think, it constantly rises to nearly three quarters sometimes slightly more.

Now I understand that it is closed when the engine is cold then opens once normal operating temperature is reached. It will close again etc if the tempurature falls below 92 degrees.
Using the same scenario if I had, say, an 80 degree one installed it would open sooner and remain open for longer however that does not explain the differing display on the guage. I would of assumed that if it reaches three quarters with the higher temp thermostat it would also reach the same with a lower temp thermostat as the engine operating temperature would be the same once they opened. But this is not the case.
Anyone care to enlighten me ?
 

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Re: [b]why Is It So ????[/b]

Did you get an after market one or a Ford one.
 

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Re: [b]why Is It So ????[/b]

Does it have bypass hole/s in it, I could be wrong but you did drill a 3mm hole in the thermostat correct ??

Jason
 

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Discussion Starter #5
Nope it already had a hole in it with a little toggle thingy through it. But that shouldn't effect it should it if both thermostats would be open at normal operating temperature.
 

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I thought with the toggle thing they basically caused a closed thermostat, so the temp would be higher then drop then back up, but you seem to have just higher temp all the time, maybe it is defective, stick in a pot of water and bring it to the boil slowly to test it.

Also are both top and bottom hoses hot, or only one of them at operating temp ?

Jason
 

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Discussion Starter #7
When on the motorway it normally sits at half. Same on most suburban roads depending on external temp. However coming out of the M5 tunnel it always rises to three quarters then drops back down. This happens constantly in this situation. However with the previous thermostat it would never rise above a quarter in the same situation.Has me stumped as to why. Temperature of the engine should be the same in both circumstances.
 

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I'd suggest using the Ford one. I put a 92 degree Ford one in and it rarely gets above half on the temp gauge. It's got the hole in it so it doesn't bounce around.

28 bucks with O ring from Ford.
 

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Discussion Starter #9
Psycho

What does yours sit at normally ? Around half or lower.
Cos one advantage with the current thernostat is I have picked up over 100klms more per tank than before.
 

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It usually sits on the R on the gauge.

It'll do that to fuel consumption. My old one was seized open, the engine took AGES to heat up, the ECU pretty much runs the injectors and full blast until it heats up. I was going through fuel like crazy. A 20 km round trip would see a quarter of a tank gone.
 
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