Water Temp Help!!

OK my 1987 Ex MOD now 200TDI did not leave the factory with a 200TDI....I have a bill for the conversion but does not say what was taken out??

Anyone following my "1st Defender Bought" (Well its actualy pre defender I believe? i.e. LR 90) anyway will know that I've been "doing it up" since I bought it, so only done about 2 miles in it until today...

It drives well and oh my after 3 Disco 300tdi's this thing is a flying machine....I mean its actualy quick!
I reccon maybe down to gearbox ratios?

Anyway the Water Gauge works in so much that its showing cold then as engine warms it moves up...unfortunatly all the way to red and beyond!! Good news is the engine is 100% not over heating...

So....few questions....
1, A wiring diagram for the gauge would be nice as I have issues wiring it up...
When I took the dash apart I labled everything but on testing the water temp it only worked without the earth lead on the screws that hold it in...?? Tried all other combos and only got it to work how its wired now...
2, (this may help answer what engine in before) It have an OIL Temp also which was wired but will not work as there is no OIL Temp sender that I can see and 200tdis from my research do not have them standard. So can I wire the OIL temp to the water temp sender as a means to iliminate things??
3, Could the Water gauge and the sender be miss matched....i.e. 200tdi but the water gauge is for a petrol? Would not have thought so?

Can't see it being the sender as they usualy read open or short (hot or cold) from experiance if faulty and this is defo altering (Verying resistance)

Once I find the issue...if I need a water gauge anyone got one?

I do love my 1st 90 tho....different to the discos but in a good way...

How do you know it's not over heating? Have you measured the temp?

Could be a nackered sensor. I'd swab it out for a mechanical gauge. They don't cost much money and you don't have to worry about all the wiring.

I had a sensor fail and it just kept flicking between hot and cold.

Defenders and discoverys have different senders in the block, a discovery one will show over heating when used with a defender gauge. Fitting a capillary durite gauge is on my list of jobs as defender gauges are notoriously vauge at the best of times

Your landy probably started life with a 2.5 na. With the correct sender, the tdi should read a bit warmer, but well below the red line. Sounds like your gauge is faulty. As mentioned above, might as well fit a new accurate Durite unit.

I had exactly the same issue with my 1986 ex-MOD 110, which has also been swapped to a 200Tdi. Nearly had heart failure when I drove it home after buying it (cheap) and saw the needle buried in the red, where on further investigation it was very clear it was not overheating. I tried different senders but no joy...same reading...so I ended up fitting a SPA unit instead which does both oil and water temp and confirmed all was well.

If you want to stick with an original gauge, Steve Parker sell a sender that will match the gauge from a 2.5 NA. As I mentioned before, it reads a bit hotter, but the 200tdi engine (in my case at least) runs a bit hotter - I couldn't get the NA much above 80 degrees.

Mines a pre defender with a 200tdi conversion too. I had exactly the same issue ie reading in the red but engine not overheating. I replaced the sender but made no difference and turned out to be the guage. Once replaced everything hunky dory again.

As everyone else says fit a proper gauge that reads in numbers not colours and know what the temp realy is,one of the best mods for an old Landy.