Land Rover Defender (1946 - ) - Series 3 Temp Gauge

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Sun 23 Sep 2007 17:44
Series 3 Temp Gauge - mrmender
Hi My 72 series 3 2 1/4 Petrol has a problem with the temp gauge. On start up it is cold as it should be after about 5 Mins running the gauge goes into the red and stays there. I've replaced the sender (£1.98!) still the same engine is not overheating. What should the resisitance be of the sender cold then hot?
I'm sure i could sort it given time, Just wonder if anybody has some quick pointers Ta MM
s
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Sun 23 Sep 2007 19:49
Landrover Series 3 Temp Gauge - Screwloose

What happens if you disconnect the sensor with the gauge at full-scale?
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Sun 23 Sep 2007 20:15
Landrover Series 3 Temp Gauge - mrmender
Hi SC No gauge still stays in cold
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Sun 23 Sep 2007 20:58
Landrover Series 3 Temp Gauge - Screwloose

If disconnecting the sensor drops the gauge to zero, then that must be the wrong sender unit.

Is there a chance that the engine earth strap is corroded? Put a jump lead from the block to battery neg.
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Sun 23 Sep 2007 22:39
Landrover Series 3 Temp Gauge - ChrisMo
Could it be a duff voltage regulator/stabiliser? I mean the box behind the speedo which stabilises the voltage to the gauges.
Does the petrol gauge function OK?

Though it is usually a dodgy earth whenever something goes wrong with LR electrics :-) I spent many a pound at autosparks when I had a series 2a.
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Sun 23 Sep 2007 23:13
Landrover Series 3 Temp Gauge - bell boy
I spent many a pound at autosparks when I had a series 2a.


I spent many an hour with bumps on my head when a mate had one,often wondered why they never had road springs fitted
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Sun 23 Sep 2007 23:34
Landrover Series 3 Temp Gauge - mrmender
Fuel gauge works ok. This is why i would like to know what the resistance for the sender cold & then for a FSD of the gauge. As SL Says it maybe the wrong sender..... But why was i getting the same problem whith the orginal sender. I think all earths are ok as it's a 5 Y/O galv chassis i will check this out in the morning
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Sun 23 Sep 2007 23:50
Landrover Series 3 Temp Gauge - Screwloose

Give me a mo; I've got a SIII genuine manual in here - somewhere....
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Mon 24 Sep 2007 00:09
Landrover Series 3 Temp Gauge - Screwloose

....And it not in there; the official SeriesIII Repair Operations Manual and not a sausage about the resistance of anything. Multi-meters obviously weren't invented in those days.

Nothing in the Autobooks one either.

Fortunately Lucas listed it in their last-ever sensor catalogue - SNB125; 32 ohms at 100C.
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Mon 24 Sep 2007 09:08
Landrover Series 3 Temp Gauge - mrmender
Thanks SL Will check this out later
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