XJ6 & XJ12 Series I, II & III 1968-1992
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Wavering / Hot Temp Gauge

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Old 06-11-2017, 02:02 PM
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Default Wavering / Hot Temp Gauge

Hi All,
Now that the summer has finally arrive here in the UK, I've noticed the temp gauge on my XJC reads high (?) and wavers. Generally it hovers around the 'L' of the word Normal however it seems to also vary a fair bit (1/4" or maybe more).
My questions are:
- Putting aside the varying reading for a second where should the gauge sit? . The 'L' is to the far right of the gauge and seems high
- The varying reading I assume is the voltage stabiliser?
Many thanks in advance
 
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Old 06-11-2017, 03:20 PM
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Should sit right about in the center...maybe a needle's width one way or the other....if the engine is running at 82ēC-88ēC.

Wavering could be the voltage stabilizer, yes.

Or could actually be the coolant temp going up-down.

How 'fast' (so to speak) is the wavering?

Cheers
DD
 
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Old 06-11-2017, 04:09 PM
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Thanks for the reply, the wavering does not have a regular frequency as far as I can tell, but maybe every 15 seconds or so, then it will steady for a while
 
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Old 06-11-2017, 08:41 PM
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I'm with Doug on the stabilser.

The "L" is too high in my opinion.

All my S2 6 cyl and V12 all sat at the "R", no matter the ambient.The V12 would sometime climb to "M" when we got above 42c outside.

My first suggestion would be to locate a mechanical temp gauge, and plumb it in, and note the temps etc.

Temp wavering can also be a lazy/sticking thermostat.

Then the pressure slides into the mix, coz if its not holding the correct pressure, things can get odd.
 
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Old 06-26-2017, 04:05 PM
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New thermostat fitted, and flushed the system (which seemed clean anyway) - success - needle now sits absolutely vertical. I haven't noticed any wavering yet but will also fit new stabiliser once it arrives......just in case.
 
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Old 06-26-2017, 10:01 PM
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Another happy customer.
 
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Old 06-26-2017, 10:41 PM
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Originally Posted by Gizze
New thermostat fitted, and flushed the system (which seemed clean anyway) - success - needle now sits absolutely vertical. ...
That was an easy fix!
(';')
 
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Old 06-27-2017, 02:59 PM
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Originally Posted by Gizze
Hi All,
Now that the summer has finally arrive here in the UK, I've noticed the temp gauge on my XJC reads high (?) and wavers. Generally it hovers around the 'L' of the word Normal however it seems to also vary a fair bit (1/4" or maybe more).
My questions are:
- Putting aside the varying reading for a second where should the gauge sit? . The 'L' is to the far right of the gauge and seems high
- The varying reading I assume is the voltage stabiliser?
Many thanks in advance
Try a new sending unit.
Walter
 
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Old 06-28-2017, 10:00 AM
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A fix is a fix, he vest of the best.


My thought is that a slightly low coolant level can cause the waver.
Here, the flush and refill fixed that.


The fascia guage, in my opinion, is misleading. The green color to the right of center is counterintuitive. Green signifies OK!! when, it is really not OK.


IFR's are a neat tool for sensing real temp's at various locations about the system. Not only intriguing, but useful in diagnostics.


I'm well acquainted with a simple over heated situation. Lots of burble and gurgle.


The latter, true, as long as there is coolant to make those noises.


When, I lost my DOHC, it lost it's coolant, in a manner, I've never resolved. No noises and the fascia guage read OK, until just before the engine quit, never to run again, at least for me.


Carl


Carl
 

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