Thought I would share this,cos it may help someone out of trouble(it did me anyway
).....
The sender for my new temp gauge was a very slim nptf summat or other. The orig sender was a larger heavier thread (fifer knows!)Anyways.I tried to buy an adaptor to get the new sender into the block...no luck,and in any case this would have meant the end of the new sender would sit within the adaptor,not in the water flow. So what I did was broke out/drilled out the old sender internals to leave the steel outer collar with thread on outside that fits the block. I then tapped the hole in the centre 10mm. The new sender with nptf thread,I run a 10 mm die down it to re thread it,(its brass and easy to re thread,but be careful) Old sender collar goes into block,new sender threads into this.I also cut a little off each end of the old sender collar to allow the new sender more protrusion into the water flow.I then used a dowty(sp?) washer under the new sender to get a good seal.