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| jst Member Since: 14 Jan 2008 Location: Taunton Posts: 8020   
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if the heater blows hot all the time when set to hot then there is no air lock.
sounds more like an earth issue on the gauge as its a rapid movement down when the temp is moved up or down Cheers James 110 2012 XS Utility 130 2011 M57 bespoke Camper 90 2010 Hardtop 90 M57 1988 Hardtop |
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5th Dec 2013 7:06pm |
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| hoarder Member Since: 04 Nov 2008 Location: Cumbria Posts: 41 
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Thanks James. I've cleaned all the earth connections this afternoon. Will take her out for a spin in the morning and report back.
Cheers Ian |
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5th Dec 2013 7:34pm |
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| hoarder Member Since: 04 Nov 2008 Location: Cumbria Posts: 41
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Update on my cooling problem. New VDO temperature sender fitted to the Madman EMS gauge. All engine earths in good order. Took her out for a spin & after a few miles... same fault. I cannot get my head around how moving the temperature lever on the heater causes an almost instant return to 'normal', after all, the lever controls a simple flap to divert air to the blower! Even checked to see that the control cable was not fouling the wire to the sender.
Later on I changed the expansion tank cap - thought I'd sorted it, but after approximately 20 miles, temperature started moving about again.   |
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7th Dec 2013 4:44pm |
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| Skye_Rover Member Since: 29 Aug 2013 Location: Skye Posts: 85  
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It sounds like the thermostat is still dodgy here; I know that you said that you changed this for a genuine part, but what you are seeing is a problem of the control of opening on the thermostat. The heater is running on the bypass coolant circuit that affects the way that the 'stat is opened, and it seems that making the coolant stream that opens and closes the 'stat either hotter or colder is "waking up" the 'stat to get to a control position.
If I were you, I'd first look at the new thermostat position in the housing - is it seated into housing properly, and is the bleed hole at 12 o'clock ie. upwards? Assuming that everything is perfect here, the next thing to consider is the coolant itself - is it a decent Longlife (pink) antifreeze to 50%? The quality and concentration of the antifreeze will affect the heat transfer properties of the coolant mix. Assuming everything is fine, the next thing would be to thermocouple into the heater outlet hose and look to see what that temperature is doing, especially as the heater control is moved during driving. If the coolant temperature is swinging wildly when the temperature lever is moved, then you have a blockage/restriction somewhere in the heater and/or bypass circuit, and a general flush and/or rod-out of all the hoses and pipes is required. That should include a visual check on the bores of the hoses to make sure that no delamination is occuring (which will worsen as the coolant temperature rises). Hope you are able to get to the bottom of this one - let us know! Roads? Where we're going, we don't need roads. |
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8th Dec 2013 12:41am |
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| jst Member Since: 14 Jan 2008 Location: Taunton Posts: 8020
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try it without the stat, modify one to remove the central bit so it still has the footvalve Cheers James 110 2012 XS Utility 130 2011 M57 bespoke Camper 90 2010 Hardtop 90 M57 1988 Hardtop |
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9th Dec 2013 9:17pm |
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