76 cj 258 temp gage?

What engine????

The 258's temperature sender for the gauge is on the top rear corner of the head and has a purple wire on it.

Are you maybe looking at the early type of CTO valve up front there? That would be the coolant temperature override for vacuum switching things like the canister and/or EGR valve and/or timing depending on emissions.

Mike

i didnt realize there were different 258"s, how would i teel them apart?

There aren't different AMC 258s. The 258 and its older brother, the 232 (same engine, shorter crank), remained virtually the same throughout their production runs, with only minor variations in the number of holes bored and threaded as needed to add accessories. As Mike said earlier, the temp sender for the 258/232 is a small plug screwed into the right rear corner of the head with a 3/8" long threaded piece sticking up out of it. Attached to it should be a single purple wire, if it is the original wire it will likely have a moulded right-angle (Ford-style) connector on it. It will be down behind the valve cover, covered with old oil and grime so it will be hard to see. Anything else going into the water jacket is part of the emission control system.

If what you are looking at looks like these: it is a CTO (Coolant Temperature Override) vacuum switch, part of the emission control.

Since you are playing with your gauges, here's how to troubleshoot them:

Here's a handy site that discusses all the other stuff under the hood:

And just for posterity (someone will need this eventually), here's an interchange chart for Jeep CTOs:

Good luck, happy hunting.

Steve G wrote: