Series 3 Temperature gauge reading hot

Re 10v vs 12. The 12 v supply varies with battery charge so to get the gauges to read the same regardless of battery charge they run on a 10v supply. There's a liitle box behind the dash that has a heater coil and bimetallic strip (its VERY low tech) and it averages 10v. The gauges should come off of that, but I have a feeling the oil gauge does not but tempand fuel gauges do. Follow the wires. voltmeter wont work as its an average 10v and the voltmeter will jump all over the place from 0 to 12.5..

Welcome to the joys of old Land Rovers!
A laser thermometer will give you some peace of mind that it's not actually overheating, then you can spend the next few days/weeks/months figuring out why the gauge is wrong...
If your engine is from a 90/110, it should have an 11H engine number, in which case it may have the wrong temp sender. I don't think you can identify the sender just by looking at it, but a non-genuine Series sender is cheap enough to try. The threads are the same on the Series and early 90/110 senders.

If that doesn't fix the problem then it could be the gauge itself, or the stabiliser, or the wiring. If the wire to the sender is shorted to earth, the gauge will go to max as soon as you turn on the ignition. Does the gauge read zero if you disconnect the sender?

I've spent (wasted) a lot of time trying to get snese out of my temp gauge. I have settled for "it goes up after the engine has been running a while and it goes down when it has stopped" any further accuracy is an unexpected bonus.

You can also use the "heater" output as a guide:
heater cold = engine cold
heater lukewarm = engine normal temp
heater hot = engine overheating

I bought a "laser guided" temp gauge for very little on Ebay and it is great for seeing the temp of hose and thermostat housing etc, and seems very accurate. I can also tell now if my son is bullshirting me when he says he has a temperature and wants a day off school.

Hi everyone, thanks to all for responses and help/advice. So, managed to find out my early Landrover 90 engine had a 5/8 thread on the temperature sender. Contacted mini spares who checked and confirmed their capillary gauge was 5/8 as well. Here’s it fitted, working well and yesterday it showed my running temperature to be between 80° and 90°.

As you can see, I’m used a wee bit of PTFE on the thread; wasn’t sure if this was needed but wanted to be safe. Fed the sensor through with the speedo cable. The bracket was originally right angled for mounting on a horizontal surface but just bent it out so I could bolt it on like so.

Some photos. The sensor with PTFE.

The speedo cable hole.

Gauge and bracket.

Finally, what I ordered.

That temp is fine. Looks like you have an 88’ c thermostat. Ok to 100’c
At least you can now spot any water probs easier than the normal gauge

Sort the pipe work between the heater matrix & front of engine. Otherwise it will rub on the HT leads

Looking good

And now Highlander will know what his engine temp is while those who keep messing with old gauges [ that were not that good in the first place ] old voltage regulators and forty year plus wiring are still guessing.

Glad it’s sorted, it looks like it would fit in the precautions holes in the oval slot to left of gauge if you want it neater

Even worse Steve....... I put it in front of the vent levers.... it will be moved.

It probably would fit in that centre panel, Some had a clock there.

nice one, same guage i have

Bloody spell check

steve2286w said:

Glad it’s sorted, it looks like it would fit in the precautions holes in the oval slot to left of gauge if you want it neater

Click to expand...

Meant to say pre drilled holes , yes I have my oil gauge there too, just trim black material in hole