series 3 200di water temp sender

Hi All
My temp gauge on my series with a 200td defender engine is reading a tad hot I thought it was the common problem of the 200 temp sender not being right for the series 3 temp gauge, so I ordered the Steve Parker conversion adaptor and a original series water temp sender, The thing is It turns out I don't need the adaptor the series sender screws straight in, is this right? and the sender ive taken out looks just the same as the one i have just put in, I haven't taken her out yet to get her up to temperature so I don't know if i've cured it yet just got thrown off by this, any one any idea ?

update
it looks like the 200tdi defender water temp sender and the series 3 water temp sender are the same thread 5/8 UNF so why is the series gauge showing hot, is it because the defender one is longer ? and the series one too short to give a good reading or have I really got a overheating problem ? thanks all and have good bank holiday weekend enjoying your land rovers

Is it not something to do with the voltage? Do series instruments not work off 10v and the disco/defender work off 12v, so the 200Tdi one under-reads because its getting less power? Might have a different internal resistance for some other reason.

I imagine the difference is in the resistance rather than thread size.

Have you tried it out yet?

thanks all just tried it and its still running hot so not sure whats going on Ive emailed Steve Parker where I got the series sender from to see if they can throw any light on it (really good company to deal with by the way when it comes to conversions) ill let you know what they say, I thought that the 200tdi defender and the 200tdi discovery would be the same sender but there not, well not in thread size anyway, if it was a discovery engine i just screw in the adaptor then the series sender and bobs your uncle so why it wont work in a defender not needing the adaptor ive no idea. head scratching time but isnt this why we enjoy working on land rovers especially converted ones

By the way I see what your both saying about voltage and resistance but with the original defender sender in it seems to over read

I had a similar issue with a 300tdi engine reading hot with a 90td sender and guage. As mentioned above I believe that although the kit may look the same its the variance in resistance that gives the hot reading. I cured mine by installing a replacement sender and a smiths 2inch temperature guage, in other words replacing all the kit with the parts supplied irrespective of whether it looks the same or not

Cheers

200TDi runs hotter than the Series engine, like you I have a defender engine with the Series sender, runs with the needle just at the top of the N mark.

Mine also just at the top of the N mark.