7120 head with a renix style guage sensor?

Ive read that one way to tell if you have a renix is the coolant temp sensor (guage) in the drivers side rear of the the head. Strangely my renix head has this plugged and my 7120 head has a sensor.


So did the previous owner put the sensor in? or did some come like this?

2686 (RENIX) and 7120 (OBD-I) heads both have a 1/8" NPT tapped port for a sensor to drive the operator indicator (be it lamp or gage.) OBD-II drives it off of the CAN bus.

The best way to identify that you actually have RENIX is to look for two things, and verify they're both present: 1) The ECU should be under the IP, somewhere around your left knee. It's a flat aluminum box. 2) There is a knock sensor down low on the driver's side of the engine, near the oil sump mounting rail

The three-screw throttle body is also a decent indicator (RENIX uses three screws that go all the way through the throttle body, HO uses four screws that go through a flange at the bottom.)

My '93 4.0 has this sensor, I just looked at it several minutes ago to see how I had the sensor wired up. So, that is a 7120 head, and yes it has the sensor. I do believe they stopped putting a sensor there at some later time.

another one is the renix has the temp sensor for the engine controller in the side of the block, next to the driver's side motor mount. and the knock sensor right down there too. just in case you were just looking at a partially disassembled motor...

I was just curious because I read somewhere that 7120's are either plugged or don't have the sensor.

MpSlayer said:

I was just curious because I read somewhere that 7120's are either plugged or don't have the sensor.

Click to expand...

They do. The 0630 and 0331 heads do not have the port for the sensor (the 0630 has the boss for it, but it went unmachined. I'm not sure about the 0331.)

5-90 said:

They do. The 0630 and 0331 heads do not have the port for the sensor (the 0630 has the boss for it, but it went unmachined. I'm not sure about the 0331.)

Click to expand...

My 96 (so OBDII) had an 0630 head with the temp gauge sensor in a threaded hole at the same place as the 7120 head (rear driver's side) I used as a replacement.

sjkimmel99 said:

My 96 (so OBDII) had an 0630 head with the temp gauge sensor in a threaded hole at the same place as the 7120 head (rear driver's side) I used as a replacement.

Click to expand...

Some early 1996 heads may have been D&T for a sensor - as I said, the boss is present for it.

This means you can probably also DIY the addition of a sensor dedicated to something-or-other, as long as it's threaded 1/8" NPT.