Call Don (in the technical dept-there is more than 1 Don there) at Isspro. 888-447-7776
I think you need the K thermocouple.
Mike

 

It's weird I looked at Isspro web site they sell all there thermocoupler's seprate from the gauges and they dont say any thing about needing a certin coupler with a certin gauge

 

well I figured it out I have a old style EV gauge with an ungrounded thermocoupler so none of the newer one will work with mine(R658HT)

So since dieselmanor.com has the worst customer service ever I now have a brand new R658HT thermocoupler that I cant use $68.00 bucks down the drain. I wish I had used a vendor from the board I'm sure they would have takin care of me!! so if you ask me DONT BUY FROM DIESELMANOR.COM SUPPORT DTR AND IT'S VENDORS INSTEAD!