Relocating Cts To Thermostat Housing

[Dando]

So when I went to change my engine block mounted CTS I discovered that a previous owner has at one time attempted to change it, poorly. It has been rounded out with what looks like every imaginable tool. At this point it is becoming obvious to me that it is gonna be a pretty large endeavor to remove it at this point thanks to that PO. Probably would have to lift engine slightly and remove the motor mount and then still not quite sure what will work.

 

So while looking at my 95 motor the other day I noticed that it may be possible to relocate it pretty easily to the thermostats housing from a 91+

 

I have done some google research and I am not sure if this would be a good idea or not. I am getting conflicting answers concerning the differing temps based on the sensor being in a hotter location.

 

What does everyone think?

 

[onlyinajeep726]

You can put the new sensor in the drain port on the side of the block instead of the current CTS location, AFAIK.  They should be the same diameter and thread pitch.  The thermostat housing is likely to read a different temperature than the side of the block.

[dave92cherokee]

The 97+ xj's have the temp sender installed in the thermostat housing and seems to work pretty well, could possibly just look at getting a thermostat housing from a 97+ instead of having to modify your original.

[Jeep Driver]

My fan switch is in the thermo housing  and works well.

 

Go to the JY and pick on up for a couple of bucks.

[onlyinajeep726]

He's talking about the temp sensor for the computer, not that fan.  I'm assuming he has a Renix MJ.  There are three temperature sensors:

• The CTS, which is in the side of the block and is strictly for the ECU
• The fan switch temp sender for just the Aux. fan
• Temp gauge sender for the gauge on the instrument cluster

If the CTS is relocated to the thermostat housing, it won't read correctly IIRC, and the ECU will not run the engine optimally.  That's my understanding of it, anway.  I may be wrong, though.
 

[Dando]

Yes I was talking about the CTS, I have already relocated it to the HO thermostat I installed on my renix this am.

[Eagle]

He's talking about the temp sensor for the computer, not that fan.  I'm assuming he has a Renix MJ.  There are three temperature sensors:

• The CTS, which is in the side of the block and is strictly for the ECU
• The fan switch temp sender for just the Aux. fan
• Temp gauge sender for the gauge on the instrument cluster

If the CTS is relocated to the thermostat housing, it won't read correctly IIRC, and the ECU will not run the engine optimally.  That's my understanding of it, anway.  I may be wrong, though.

 

In this case, you are correct. The sensor in the side of the block is what provides data to the ECU in the Renix system, and relocating it to the thermostat housing might result in a difference in reading. The question is what that would affect. In the HO (Chrysler) system, the temp sender in the t'stat housing provides all the data to the ECU, and the ECU controls (among other things) the auxiliary fan. The Renix system has a stand-alone sensor to activate the auxiliary fan, so that's not a concern. As far as I know, the only things the ECU uses the temperature data for is to switch from open loop (warm-up) to closed loop (normal run) mode. That change takes place at something like 165 to 175 degrees, which is well below the normal operating temperature. If the change in mode takes place a few degrees cooler or a few degrees warmer, I doubt the driver would even notice.

 

Interesting -- I started this post with the idea that it wouldn't work, then as I walked myself through it I came to the view that it just might work.

[Dando]

I will post pics shortly to show it all installed