So where did I get 208* from?

Don't ask me. All I did was provide factual info on a Renix as monitored by the factory tester.

IIRC, Who's on first, and I don't know is on second.

Oh....ok, I thought u said the sensor had a "designed in" 208* trigger temp (my bad)....but what u said was the scanner indicated 208* at the stat cover when the fan came on, correct?

So.......the "in rad" sensor has a 176* trigger temp and the "in the stat cover" sensor has a 218* trigger temp, right?

The scanner indicated a CTS reading of 208* IN THE BLOCK of a Renix when the e-fan came on, as triggered by the radiator fan switch..

The temp gauge on the dash, as read by the SENDER in the back of the head, read between 200 and 210.

So a Renix motor has a temp sensor in the block?

CTS is in the lower block in one of the block drain holes. The sender is at the driver's side rear of the head. Fan switch is about 1/3 up the radiator tank on the driver's side.

So, basically what I'm saying is the sender at the back of the head reads between 200* and 210*. The CTS reads 208* down in the lower part of the block. The fan switch, about 1/3 from the bottom of the radiator in the left side tank, kicks the fan on at 208*.

Coolant flows in the gallons per minute and only holds 2 gallons. There ain't a huge variation in temperature throughout the entire system as all the "scientists" seem to guess.

Ah ha, I learn something new everyday here......there r 3 coolant sensors on a Renix vs 2 sensors on '91 thru '96 HO motors and only 1 sensor on '97 up HO motors, right?

On the Renix motor, what is the block sensor sending a signal to?.....the ECU only? Does the rad sensor signal direct to the efan or direct to the ECU and then to the efan?

On that one day in Arizona when the ambient temp dips down to tolerable, have u ever pointed a IR temp gun at the cold tank on the rad out of curiosity after the motor has warmed up?

Block sensor to ECU only

Radiator fan switch independent of ECU. Has it's own relay.

Temp sender in back of head.

I live a mile high in Arizona, not down where only coyotes, roadrunners and lizards like it.

We see 0*F in winter.

So out of curiosity, on one of those 0* days have u ever shot your IR gun at the cold rad tank, after the motor has warmed up?

No.

With the closed system, on a 20* day, I can drive 2.5 miles and be up to where the factory stat opens. Nice and cozy warm.

I had 3 Stant 195 Superstats that left me freezing on 3 of our Jeeps.

Dayum! That is one toasty XJ.....wonder what makes it get so hot, so quick, when it's so cold outside? On a 70* morning, is it at operating/t-stat temp before u've backed out of the garge?LOL

Factory stat.