Temp gauge up and down

Hi there. Recently got an ex RAF 90 rag top. Love it. Just noticed the temp gauge shoots right up to the top when driving about town but then whilst driving it'll drop down to normal position but then fluctuate back up. Sometimes it just sits steady where it should be I know we have had this recent burst of hot weather. Haven't got round to changing coolant in it yet since I got it so could be the old original stuff full of crud. Any suggestions would be greatly appreciated. It's running fine otherwise.
Cheers.

what engine does it have?

Jesterr6216 said:

Hi there. Recently got an ex RAF 90 rag top. Love it. Just noticed the temp gauge shoots right up to the top when driving about town but then whilst driving it'll drop down to normal position but then fluctuate back up. Sometimes it just sits steady where it should be I know we have had this recent burst of hot weather. Haven't got round to changing coolant in it yet since I got it so could be the old original stuff full of crud. Any suggestions would be greatly appreciated. It's running fine otherwise.
Cheers.

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rad blocked, fan not working, stat not opening fully, pump . . . . .
you get the idea.

Bad conection/ pos earth onTG .

disco 200tdi?

temp sender is incompatible with defender temp guage

nesponge said:

disco 200tdi?

temp sender is incompatible with defender temp guage

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iv had something similar going on with mine it has a discovery 200tdi in it now which sender will it need putting in def 200 or def td ?

This is the temperature sender you need

Steve Parker Land Rover Spares, Details of 200 Tdi Discovery > 90/110 Temp Sender, Spare Parts, Freelander, Defender, Range Rover Parts, Land Rover Conversions

It's a 2.5 litre nat aspirated. Gonna try taking stat out and cleaning plus flushing old coolant out and putting new stuff in. May have been lying in storage for up to 10 years so would guess would need doing. Cheers gents for replies.

take the stat out 1st and see if it makes a difference.

A good flush and fresh coolant next along with checking your gauge wiring.

check your fan also.

G

This started happening to my 1994 NAS D-90 on long trip. Since then I have replaced radiator, clutch fan, hoses, water pump, all three sensors, checked groundings, flushed system, checked all wires, etc., and the problem has only gotten worse. Now the needle moves beyond the red zone and stays there no matter how far I drive it. It use to return to normal if I shut off the engine and then restarted it. The only thing left for me to do is replace the gauge itself but I am not confident that will work. Any other ideas would be appreciated.

EDMULRENIN said:

This started happening to my 1994 NAS D-90 on long trip. Since then I have replaced radiator, clutch fan, hoses, water pump, all three sensors, checked groundings, flushed system, checked all wires, etc., and the problem has only gotten worse. Now the needle moves beyond the red zone and stays there no matter how far I drive it. It use to return to normal if I shut off the engine and then restarted it. The only thing left for me to do is replace the gauge itself but I am not confident that will work. Any other ideas would be appreciated.

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Before you change the guage itself at £18, i'd recommend you do a 200tdi conversion. If this doesnt work try a 300tdi conversion. If these options fail i'd begin to look seriously at changing the guage. But not before.

thanks. all ideas welcome. (did you mean 180 pounds? Here in US the temp gauge goes for $269.)

EDMULRENIN said:

thanks. all ideas welcome. (did you mean 180 pounds? Here in US the temp gauge goes for $269.)

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No..i meant £18. But I can send you one, postage free for $160

thanks. it may come to that. why no one here in the us can solve this I do not know. the computer shows that everything is working just fine and the vehicle is not actually overheating. i would just drive it and ignore the false signal but I am concerned that at some time I will miss a true signal of a problem.

Drop me a pm..i take paypal..i can send a dozen which you are welcome to sell on to similarly affected people...

storm99 said:

Before you change the guage itself at £18, i'd recommend you do a 200tdi conversion. If this doesnt work try a 300tdi conversion. If these options fail i'd begin to look seriously at changing the guage. But not before.

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:rofl:

EDMULRENIN said:

thanks. it may come to that. why no one here in the us can solve this I do not know. the computer shows that everything is working just fine and the vehicle is not actually overheating. i would just drive it and ignore the false signal but I am concerned that at some time I will miss a true signal of a problem.

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Its because your landrover knows deep down that it is british and it objects to being in America. Its just doing it to **** you off

Check that the grounding of the chassis is good. It looks like a "p" clip holding the -ve cable to the chassis side rail, forward of the battery box. It's bare wire under this clip and over time it goes loose, causing ( in my case temp gauge fluctuations and randomly flashing head lights ) various electrical gremlins.
Hope this helps.

Been quite amusing checking up on my thread, cheers for all the input guys. Flushed the rad out and the old coolant didn't look too bad at all. Put fresh coolant in, connected it back up, and guess what, first drive out and after 5 mins of sitting bang on the middle the needle pinged up to the max. Then after 3 mins dropped down to the middle. Then pinged back up, and so on.....
So, being a novice, I'm looking at the Haynes manual and can I work out what/where the thermostat is? Can I stuff. Mine's is an ex-RAF 90 so if anyone can point this idiot in the right direction it would be appreciated. I'll check the previous post's suggestion as well, but think I'll give fitting a 200Tdi a miss.

In case anyone is still following this thread, Eureka!!!! I recently replaced the knackered black plastic binnacle with a lovely Raptor powder coated one, so had to have the dials etc out, and low and behold, there was a little locking washer on the back of the temp gauge, which I decided to leave off as it sat under the earthing cable. Result? The temp gauge sits exactly bang on centre, no more shooting to the max, then back down.