i have a v2 STI and want to fit a after market water temp
gauge, where is the original sender and would you recomend using this
or install another sender,

 

An aftermarket gauge will have its own sender unit, and normally it is best to stick into the top radiator hose with an adaptor

 

I've done this.

First off, you can't use the original sender for an aftermarket gauge. Most, if not all, senders are made to go with a particular make of gauge.

Second, there are TWO water temperature senders: one for the gauge, with ONE wire coming out of the top, and one for the ecu with two wires. Don't muck about with the one for the ecu.

If your new sender will fit where the present one is, then do that, and move the sender from the car's OE gauge into the top hose: you need a fitting like this: http://www.ebay.co.uk/itm/WATER-TEMP...item20b8413406

That's the way I would do it, since your new, hopefully more accurate, gauge, will now be in the position Subaru designed to take water temperature from, the best position, with the car's gauge in the NEXT best.

You may have to slightly extend the OE gauge wire to fit it there, easy to do, and don't forget that any sender fitted into the top hose will PROBABLY need the outside of the sender, or the bit it's screwed into, connecting to a nearby earth

BTW: I started off with my car's own gauge disconnected, but couldn't get on with seeing the needle below zero all the time, so wired it back in.

 

thank's
i have a new sender and top hose fitting,
so top hose it is then.

 

Not sure what that means.........new sender where the old one was, in the block, correct place for it, old sender removed from block, in new fitting, is best