Collant temp - sensor - sender

First, let me say that I don't post until I have searched. I either become well educated or well confused. In this case I am a little of both.

I have an 89 block with renix electronics. I have a 0630 head, with the newer (91+ I think) water neck. I am building htis truck from the ground up, with 3 other vehicles as reference (2 for parts).

As I understand it, there are 3 items in this game... a temperature SWITCH to control the electric aux fan... a coolant SENSOR that read coolant temp and only talks to the renix cpu to adjust a/f ratio... and a temperature SENDER to show temperature to the guages...

I didn't know about the sender. The 0630 doesn't have a hole tapped in the head for one. I was going to move the SWITCH for the aux fan from the lower hose up to the newer water neck. The coolant sensor was going to be in the block where it belongs...

problem #1 - no hole in the head (boy it feels like ith though)

problem #2 - the drain plugs are stuck. 8mm rounded out to a circle.

I am not a tool... the drain plugs will have to be drilled and tapped to mount the sensor in THAT location (both are crap - I think my machinist must have put a thread locker or something in there).

To drill / tap the head and now the block, the motor will ahve to be removed (to do it right)...

I have read and read, and I can only say that I think I must have missed something. Do I need all 3 - sensor, switch, sender - or can some wiring be combined? Does the sensor need to touch coolant, or just the block? Can I leave the aux switch down low and put the coolant sensor in the h20 neck?

I am rattled. I was hoping to start the stroker up soon. I just need exhaust and fluids. (and now this.)

I'm running a 99 engine in a 96. I moved the temperature sender in the head to the unused switch location in the radiator by drilling and tapping the brass plug. I'm not happy with this set up as the gauge doesn't read the actual engine temperature. I now plan to drill and tap the t-stat housing and install the sensor facing forward. I have a spare t-stat housing to play with.

From what I know about the Renix system, you can not combine sensors. The critical one is the computer. You can always put a switch on the fan. Our YJ has aftermarket fans on a switch and it works fine.

Tom

I like the idea of moving the sender to a drilled and tapped hole in the water neck. Anyone else done this? (I will search for this). I could then move the collant sensor to the water neck as well, and put the temp switch in it's original location out of the radiator. Not optimal, but does anyone see any problems?

Thanks - Brad

QUESTION:! the drian plugs on the side of the motor... are they 5/16" square or a 8mm hex? I am at work, and can't check, but I also can not see to well into the area... (89 renix block)

Thanks

anyone have any other thoughts?

MaineJeepah said:

QUESTION:! the drian plugs on the side of the motor... are they 5/16" square or a 8mm hex? I am at work, and can't check, but I also can not see to well into the area... (89 renix block)

Thanks

Click to expand...

The coolant ones? I think they are 8mm SQUARE. Sort of a special size socket (I think napa can get it) or you could make your own by grinding down square stock.