Thermostats.
Submitted: Wednesday, Sep 06, 2006 at 19:44
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Member - Axle
Hi.
Had trouble with the temperature gauge registering below cold every time i went down a long
hill. Replaced the thermostat and everything is fine, but it got me thinking as to how much those little buggers are working to regulate the
water temperature when the motor is constantly on and off load
Cheers Axle.
Reply By: Marn - Wednesday, Sep 06, 2006 at 21:40
Wednesday, Sep 06, 2006 at 21:40
I thought once they opened they stayed open until the car completely cooled down again, not regulating the flow as the car went along. Cheers
AnswerID:
193226
Follow Up By: Doggy Tease - Wednesday, Sep 06, 2006 at 22:15
Wednesday, Sep 06, 2006 at 22:15
Your pretty close to right there i think Marn. At least on my truck the thermostat stays completely closed till 82deg is reached, then it slowly opens to a max temp of 92, by which stage it is fully open. It then stays fully open above that temperature, and at 98deg the horton fan cuts in and brings the temp back down. However, as the temp rises or falls after that, i think the thermostat follows suit. My temp guage will not go below 82deg, untill the motor has been turned off for awhile.
meow.
rick.
FollowupID:
451071
Reply By: Member - Jeff H (QLD) - Wednesday, Sep 06, 2006 at 22:14
Wednesday, Sep 06, 2006 at 22:14
Interesting: what's the vehicle, and what pointed you toward the thermostat?
AnswerID:
193229
Follow Up By: Member - Axle - Thursday, Sep 07, 2006 at 07:10
Thursday, Sep 07, 2006 at 07:10
Landrover defender tdi 300. with the van on going down a long steep run the temp went back to cold, so i just thought the thermostat must be sticking, not closing back as the temp drops. A new thermostat has fixed the prob anyway.
FollowupID:
451103
Reply By: Member - Phil G (SA) - Wednesday, Sep 06, 2006 at 22:51
Wednesday, Sep 06, 2006 at 22:51
Pretty simple mechanism - wax expands with heat to open it and contracts with cool to close it. I guess thats why they haven't changed in a lot of years.
AnswerID:
193235
Follow Up By: Member - Axle - Thursday, Sep 07, 2006 at 07:27
Thursday, Sep 07, 2006 at 07:27
Agree Phil. they can be motor destroying though if gauges don't pick up anything irregular.
Axle
FollowupID:
451105
Reply By: Drew - Karratha - Thursday, Sep 07, 2006 at 16:45
Thursday, Sep 07, 2006 at 16:45
Is the temp sensor near the highest part of the cooling system when going down
hill?? The reason I ask is the only time I have had the temp gauge drop on my 80 series was when the
water pump buggered up and the coolant rapidly leaked out as I was driving. I noticed the temp drop every time I went around a corner- the temp sensor ended up in air instead of coolant and when it did the temp gauge dropped. I gather you had to top up the coolant after replacing the thermostat - have you checked for a slow leak to ensure it wont happen again in a few days / weeks etc??
Drew
AnswerID:
193311
Follow Up By: Member - Axle - Thursday, Sep 07, 2006 at 17:13
Thursday, Sep 07, 2006 at 17:13
Hi Drew, Know what your saying, did top coolant up again, dosen't appear to be any leaks its been about a fortnight since i did it and the
water level is spot on. Will be keeping a close watch on it though.
Cheers axle.
FollowupID:
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Follow Up By: Member - Stephen M (NSW) - Thursday, Sep 07, 2006 at 22:32
Thursday, Sep 07, 2006 at 22:32
Yep agree with you there Drew, I always say to my wife if guage drops from normal operating temp on guage to cold stop straight away cause its as bad as the guage going upwards cause it wont get a temp reading if it's air only instead of coolant around the sensor. Regards Steve M
FollowupID:
451282