Yes, it sure does. It's my preferred setting in the winter. Less draw on the motor.
Unless of course there is heavy precipitation. Then, I switch it over to "Auto".

 

I noticed something strange today on the Ultra Gauge. Not sure if it's normal operation or not.

Temps =< 190F the system would go into Open Loop status. Right, that little halo looking icon in the upper right hand corner of the UG - represents open or closed loop cycling, right?

Now, I'm not certain what determines open or closed loop cycling on these motors, is it O2 lambda values or water temp sensory? Both?

After noticing Open Loop status - I began monitoring O2 values.
Bank 1 Sensor 2's readings were very erratic both at idle and while cruising. Anywhere from .1 up to .8ish. Whereas, B2S2's readings were stable w/in .450-.600. Weird.

To echo the above, the system only entered open loop when the temps dropped under 190F, while cruising down the road. I know Open loop is triggered w/ WOT pulls - but this was not my case.

Anyone have an insight as to what I experienced with the Open / Closed Loop cycling??


Update:
After a bit of reading I believe it's time to swap out the rear 02's (124k miles on the originals). I am lead to believe the ECU is acting upon false information from the "worn" B1 S2.

 

Any word on the temps?

I've been monitoring mine a little more. Saw 204.8 yesterday. it was a warmer day and my truck had been sitting in the sun, and i was in traffic at the time. but made me think of this thread.

 

My disco has been all over the place.




Still running between 194 and 206. Saw 208 after a hard acceleration yesterday before coming to a stop light. Then it idled down to 201, then 197. I let it sit for about 10 minutes idling and it was only 199.
However IR gun readings just don't support that. Radiator is still cold. thermostat housing and hoses on the engine side are only 160-170, Including the steel tube coming out of the engine that feeds the top of the radiator.


I'm puzzled at this point. I ordered a radiator, and will put it in when I have time, but right now i'm just going to keep running it.

 

I have been running my heater one notch under WFO and stays between 194 and 199