Coolant fan override switch

[g_man1146]

The pump is attached to a PTO on the curb side of the transmission
and the only lines I see go to the fan. No filter bypass on mine.
This setup is quite different than that on my previous '90 PT40 8V92.

Rich D. '99LXi43' CT


--- In WanderlodgeForum@yahoogroups.com, "Gregory OConnor"
wrote:
>
> Ok,Is the fan pump on the S60 also the Powersteering pump. Is there
a
> filter by pass?
> GregoryO'Connor
> 94ptRomolandCa
>
> --- In WanderlodgeForum@yahoogroups.com, "g_man1146"
> wrote:
> >
> > Gregory,
> >
> > On the later model Series 60's the fan bypass valve diverts
> > hydraulic oil around the fan motor to allow the fan to run at a
> > lower speed by sending the oil back without going through the
> > fan "motor". If the bypass valve fails, you get full RPM of the
fan
> > as all of the oil is directed to the fan motor. This has nothing
to
> > do with a filter bypass. The bypass valve can also be tested by
> > plugging the return line that goes to the bypass valve thus
forcing
> > all oil through the fan motor.
> >
> > Rich D. '99LXi43' CT
> >
> >
> > --- In WanderlodgeForum@yahoogroups.com, "Leroy Eckert"
> > wrote:
> > >
> > > Yes.
> > >
> > > Leroy Eckert
> > > 1990 WB-40"Smoke N Mirrors"
> > > Nicevile, FL
> > >
> > >
> > > ----- Original Message -----
> > > From: Gregory OConnor
> > > To: WanderlodgeForum@yahoogroups.com
> > > Sent: Monday, February 19, 2007 8:02 PM
> > > Subject: [WanderlodgeForum] Re: Coolant fan override switch
> > >
> > >
> > > David, Bypass and override are two independent features. I
> > believe
> > > bypass is a safety feature for a clogged hydro oil filter.
> > Bypass is
> > > not triggered by the override dash switch
> > > GregoryO'Connor
> > > 94ptRomolandCa
> > >
> > > --- In WanderlodgeForum@yahoogroups.com, David Brady

> > > wrote:
> > > >
> > > > Hi Rich,
> > > >
> > > > Thanks for the help. When I return to the bus I'll try your
> > test.
> > > > I guess if the fan speed increases, then the problem is
> between
> > > > the dash switch and the "bypass valve". Alas, no wiring
> > schematics..
> > > > I'll let you know what happens.
> > > >
> > > >
> > > > David B
> > > > '02 LXi, Smokey
> > > > NC
> > > >
> > > > g_man1146 wrote:
> > > > > Hi David,
> > > > >
> > > > > AS others have stated, a fan over-ride failure should
fault
> > to
> > > high
> > > > > speed. If you are not getting high fan speed with the air
> > > conditioner
> > > > > on or with the switch set to "over-ride" locate (assuming
> > Detroit
> > > S60)
> > > > > a connector plug at the rear of the engine compartment
> > (closest
> > > to rear
> > > > > bumper) on the fan side. You should see a hydraulic hose
> > from the
> > > fan
> > > > > motor to this block (bypass valve) and wires coming from
> it.
> > If
> > > you
> > > > > disconnect the connector plug on these wires, the fan
> should
> > come
> > > up to
> > > > > full RPM. (ROAR) If it increases but not fully, the
problem
> > may
> > > lie
> > > > > with the hydraulic pump which is attached to the PTO on
the
> > curb
> > > side
> > > > > of the Allison or with the hydraulic bypass valve. BB
makes
> > > changes all
> > > > > the time and my coach (3 years older) may not be set up
the
> > same.
> > > If
> > > > > you are not overheating on long hills everything may be
> > normal. I
> > > > > experienced an overheating situation only in extreme
> > situations
> > > and
> > > > > determined the problem to be a faulty hydraulic pump
> > supplied as
> > > part
> > > > > of the PTO recall from BB. The pump did not have
sufficient
> > > capacity to
> > > > > run the fan at full speed. They supplied a new pump and
> > labor to
> > > > > install. The fan motor is actually rated at about 40 HP
at
> > full
> > > > > capacity. No wonder it is designed to cut back when not
> > needed!
> > > > >
> > > > > Rich D. '99LXi43' CT
> > > > >
> > > > > --- In WanderlodgeForum@yahoogroups.com, David Brady
> >
> > > wrote:
> > > > >
> > > > >> Folks,
> > > > >>
> > > > >> On my '02 LXi, with the engine at idle, the fan seems to
> > rotate
> > > > >> at 400 rpm or so (give or take, lol), when I enable the
> > override
> > > > >> switch there doesn't seem to be any change in fan speed.
> > Should
> > > > >> there be? or are there other parameters at work hear;
> i.e.,
> > > engine
> > > > >> temp, etc. What are the common failure modes of the fan
> > override?
> > > > >>
> > > > >> Thanks,
> > > > >> David Brady
> > > > >> '02 LXi, Smokey
> > > > >> NC
> > > > >>
> > > > >>
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > Yahoo! Groups Links
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > >
> > > >
> > > >
> > > > [Non-text portions of this message have been removed]
> > > >
> > >
> > >
> > >
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> >
>