You know, I kinda remember the grey van cooling right off coming down
some of the passes between Grand Targhee and the coast on the way back from
a festival there many years ago.  Miles of closed-throttle overrun in a
loaded van.
     We're talking the needle halfway to the LED and in 95 degree temps
too.  So at the time it was a good thing, but I can see that you would be
less than thrilled with that in wintry conditions.  You need input from the
Colorado crowd.

On Dec 1, 2007 10:39 AM, Michael Elliott <camping.elliott@gmail.com> wrote:

> Tenterhooks? Hanging on to my every word, I bet! I have learned to keep my
> posts simple and single-subject to avoid spinning off into a thread
> unrelated to what I was asking about. In this case, the engine temp.
>
> On the downhill, the engine was cool enough to cause the ECU to go into
> open loop, as mentioned. You're right: when closed-loop, the O2 monitor
> would normally go off-scale in the lean direction with the foot off the
> gas and the engine spun up by the transmission. But when open loop, the
> injectors dump in some predetermined amount of fuel, which I saw on the
> monitor. So the engine wasn't not generating heat.
>
> I guess I better crack the Bentley's -- where is the dash temp gauge
> sensor located, anyway? I was running the heater, maybe there simply
> wasn't enough waste heat left over to dump into the radiator.
>
> So I reckon the question is whether this is normal behavior: would long
> downhill in 35F - 55F weather, with the heater on, result in an engine so
> cool that the ECU goes open loop and the temp gauge rides only about 1/3rd
> up from the full-left dead cold setting?
>
> As for mileage, there is an improvement. Can't say exactly what made the
> difference. My Mount Laguna trip is once a month (had to skip last month
> due to fire closure), so I'd rather not try one thing at a time to see
> what makes a difference as life is too short, esp. at my age.
>
> City mpg pre wheel alignment(but post changing timing and some other
> fussing about):  13.7 mpg
>
> City mpg post alignment: 15.6 mpg.
>
> Mount Laguna run pre-alignment (and pre all that other stuff): 16.7 mpg
>
> Mount Laguna run post-everything: 17.9 mpg.
>
> The rear wheels are still not aligned -- the shop didn't know how. I'll
> get that handled before the next run.
>
>
> --
> Mike "Rocket J Squirrel" Elliott
> 71 Type 2: the Wonderbus
> 84 Westfalia: Mellow Yellow ("The Electrical Banana")
> 74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
> KG6RCR
>
>
>
> On 12/1/2007 10:23 AM Jake de Villiers wrote:
>
> >      The new thermostat obviously has a lower opening temperature than
> > your original or it wouldn't have moved where the needle rides on your
> > existing gauge.  That may or may not be a good thing.
> >
> >      I'm wondering how the engine could possibly make any heat on a long
> > downhill on overrun if the fuel cut-off switch has taken the gas out of
> > the combustion chambers.  I mean, its damn cold outside and you're
> > pumping that air through the engine and there's no combustion.  Ergo,
> > you're freezing your ass off.   :)
> >
> >      Maybe you'll need to idle your way down those long grades to keep
> > the water temperature up.
> >
> >      How was your gas mileage?  We're all on tenterhooks..........
> >
> > On Dec 1, 2007 9:33 AM, Michael Elliott <camping.elliott@gmail.com
> > <mailto:camping.elliott@gmail.com>> wrote:
> >
> >     A couple months ago I replaced the water pump -- it was making an
> >     ominous
> >     grinding noise. Felt crappy when it was removed, too. Installed a
> >     new Temp
> >     II sensor and thermostat at the same time. The thermostat came from
> >     one of
> >     the usual online presences, can't recall exactly who but could find
> >     out if
> >     it's relevant. The packing list noted that it was one that was set
> >     for 10
> >     degree cooler than stock.
> >
> >     Indeed, with normal city driving at outside temps in the 70F range,
> the
> >     temp gauge seems to rest just at the left edge of the LED whereas
> >     previously it rode straight up, bisecting the lamp.
> >
> >     This morning I just returned from a two-night camping trip in the
> San
> >     Diego mountains. It was 35F this morning and the first 2/3rds of the
> >     drive
> >     are mostly downhill, a 6,000 ft elevation drop in about 60 miles.
> >     For most
> >     of the downhill portion, the temp needle sat between the painted
> >     "box" at
> >     the left-hand side of the meter face (this is a 1984 1.9L) and the
> left
> >     edge of the LED, mostly closer to that painted box than the LED. In
> >     other
> >     words, at about halfway between left (dead cold) and straight up.
> >
> >     The engine was so cool that the ECU went open-loop during long
> >     downhills
> >     (auto transmission in "2," holding road speed down), as determined
> >     by the
> >     Ken Lewis O2 monitor.
> >
> >     Once I got to the flats, in 55F temp, freeway speeds of 70 mph or
> >     so, the
> >     needle rarely kissed the left edge of the LED.
> >
> >     This is new behavior, I'm not used to seeing the engine run that
> cool. I
> >     know that a thermostat with a cooler set point may make it run
> >     cooler when
> >     it's not being worked hard, but it should keep the engine warm. I
> can't
> >     recall seeing the coolant that cold during downhills. That said,
> >     this was
> >     the coldest weather I've made that run in. But still.
> >
> >     Next month I'll make the same trip, and it could be 20F cooler. I
> >     want to
> >     be certain that the thermostat isn't, like, stuck open or anything.
> >
> >     --
> >     Mike "Rocket J Squirrel" Elliott
> >     71 Type 2: the Wonderbus
> >     84 Westfalia: Mellow Yellow ("The Electrical Banana")
> >     74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
> >     KG6RCR
> >
> >
> >
> >
> > --
> > Jake
> > 1984 Vanagon GL
> > 1986 Westy Weekender "Dixie"
> > Crescent Beach, BC
> > www.crescentbeachguitar.com <http://www.crescentbeachguitar.com>
> > http://subyjake.googlepages.com/
>

--
Jake
1984 Vanagon GL
1986 Westy Weekender "Dixie"
Crescent Beach, BC
www.crescentbeachguitar.com
http://subyjake.googlepages.com/