PT Engine Cooling Fan System

[Rick A.]

Has anyone figured out how the PT engine cooling fan system actually changes
from low
speed to high? Obviously there is a fan override switch on the dash and a
temperature
controlled switch on the engine which when activated turns the fan on high.
Question is,
what do they really turn on? or off?

thanks,
Rick Archie
85PT40
Fort Worth

[Pete Masterson]

There's a thermostat somewhere... however, the fan goes to 'high'
when (1) the dash switch "fan Override" is on and (2) whenever the
chassis AC is on.

When the switch is off and the AC is off, then the thermostat (where
ever it is) controls the fan speed. On my coach, I can't ever tell
when the fan is off or running on low speed -- unless I'm standing
outside. I can tell when the fan is on 'high' if I'm parked or moving
over dusty (unpaved) ground as the high speed really kicks up the dust.

So, unless you want the fan on high all the time, leave the fan
override switch "off" and don't turn on the chassis AC. Then, the
thermostatically controlled switch (back in the engine compartment
somewhere) will control the fan speed. (On my coach, the fan is
powered hydraulically.)

Pete Masterson
'95 Blue Bird Wanderlodge WBDA 42
El Sobrante CA
aeonix1@...



On Aug 5, 2007, at 7:11 PM, Rick A. wrote:

> Has anyone figured out how the PT engine cooling fan system
> actually changes from low
> speed to high? Obviously there is a fan override switch on the dash
> and a temperature
> controlled switch on the engine which when activated turns the fan
> on high. Question is,
> what do they really turn on? or off?



[Non-text portions of this message have been removed]

[ronmarabito2002]

Rick:

There is an alarmstat on the rear of the engine that
senses water temperature. When it reaches the correct temperature, it signals
the fan to go into high speed. I don't know all the interlocking parts, but
that typically is how it works. A failed alarmstat will keep your fan on high
all the time. Also, when you turn on the dash air, it signals the fan to run in
high mode.

R.E. (Ron) Marabito, Dallas, TX 92WB40


--- In WanderlodgeForum@yahoogroups.com, "Rick A." wrote:
>
> Has anyone figured out how the PT engine cooling fan system actually
changes from low
> speed to high? Obviously there is a fan override switch on the dash and a
temperature
> controlled switch on the engine which when activated turns the fan on high.
Question is,
> what do they really turn on? or off?
>
> thanks,
> Rick Archie
> 85PT40
> Fort Worth
>

[Rick A.]

Thanks Pete,
But I'm looking for a little more specific information. Like the actual
valve which controls
the hydraulic fan systems low speed... and likewise for the high speed? There is
a Webster
Pressure Relief Valve in this system which has a solenoid? No hydraulic shop
here can find
any information on it, as Webster has been gone awhile. Bluebird parts says
they no
longer stock it and they do not have service kits for it?

Rick Archie
85PT40
Fort Worth...where it has not rained for 2 days...

--- In WanderlodgeForum@yahoogroups.com, Pete Masterson wrote:
>
> There's a thermostat somewhere... however, the fan goes to 'high'
> when (1) the dash switch "fan Override" is on and (2) whenever the
> chassis AC is on.
>
> When the switch is off and the AC is off, then the thermostat (where
> ever it is) controls the fan speed. On my coach, I can't ever tell
> when the fan is off or running on low speed -- unless I'm standing
> outside. I can tell when the fan is on 'high' if I'm parked or moving
> over dusty (unpaved) ground as the high speed really kicks up the dust.
>
> So, unless you want the fan on high all the time, leave the fan
> override switch "off" and don't turn on the chassis AC. Then, the
> thermostatically controlled switch (back in the engine compartment
> somewhere) will control the fan speed. (On my coach, the fan is
> powered hydraulically.)
>
> Pete Masterson
> '95 Blue Bird Wanderlodge WBDA 42
> El Sobrante CA
> aeonix1@...
>
>
>
> On Aug 5, 2007, at 7:11 PM, Rick A. wrote:
>
> > Has anyone figured out how the PT engine cooling fan system
> > actually changes from low
> > speed to high? Obviously there is a fan override switch on the dash
> > and a temperature
> > controlled switch on the engine which when activated turns the fan
> > on high. Question is,
> > what do they really turn on? or off?
>
>
>
> [Non-text portions of this message have been removed]
>

[Richard Hayden]

Well my friend, I think you have it. I didn't know the name but on my coach it
is located on the street side frame rail. It hydraulic over electric. I
believe that the electric sensor/switch is still available, though I'm at a loss
to tell you where. This is one of the things on these old birds that are no
longer available. Though I imagine that a good hydraulic shop could probably
overhaul it if it is inside the valve itself.

Good luck.

Dick Hayden - '87 PT 38 - Lake Stevens, WA

----- Original Message -----
From: Rick A.
To: WanderlodgeForum@yahoogroups.com
Sent: Sunday, August 05, 2007 7:43 PM
Subject: [WanderlodgeForum] Re: PT Engine Cooling Fan System


Thanks Pete,
But I'm looking for a little more specific information. Like the actual valve
which controls
the hydraulic fan systems low speed... and likewise for the high speed? There
is a Webster
Pressure Relief Valve in this system which has a solenoid? No hydraulic shop
here can find
any information on it, as Webster has been gone awhile. Bluebird parts says
they no
longer stock it and they do not have service kits for it?

Rick Archie
85PT40
Fort Worth...where it has not rained for 2 days...

--- In
WanderlodgeForum@yahoogroups.com, Pete
Masterson wrote:
>
> There's a thermostat somewhere... however, the fan goes to 'high'
> when (1) the dash switch "fan Override" is on and (2) whenever the
> chassis AC is on.
>
> When the switch is off and the AC is off, then the thermostat (where
> ever it is) controls the fan speed. On my coach, I can't ever tell
> when the fan is off or running on low speed -- unless I'm standing
> outside. I can tell when the fan is on 'high' if I'm parked or moving
> over dusty (unpaved) ground as the high speed really kicks up the dust.
>
> So, unless you want the fan on high all the time, leave the fan
> override switch "off" and don't turn on the chassis AC. Then, the
> thermostatically controlled switch (back in the engine compartment
> somewhere) will control the fan speed. (On my coach, the fan is
> powered hydraulically.)
>
> Pete Masterson
> '95 Blue Bird Wanderlodge WBDA 42
> El Sobrante CA
> aeonix1@...
>
>
>
> On Aug 5, 2007, at 7:11 PM, Rick A. wrote:
>
> > Has anyone figured out how the PT engine cooling fan system
> > actually changes from low
> > speed to high? Obviously there is a fan override switch on the dash
> > and a temperature
> > controlled switch on the engine which when activated turns the fan
> > on high. Question is,
> > what do they really turn on? or off?
>
>
>
> [Non-text portions of this message have been removed]
>





[Non-text portions of this message have been removed]

[erniecarpet@...]

That control and hoses that run into it are to the rear of the tag axle mud
flap on the street side. I know when I had to get under there to remove a hose
that went to my cooling fan motor for the radiator. Hope yours isn't as
messy as mine was~

Ernie Ekberg
83PT40
Livingston, Mt




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[Non-text portions of this message have been removed]

[Leroy Eckert]

There is an Alarmstat control that actuates a hydraulic valve that controls fan
speed. Full on or Idle. All factory Alarmstats I have seen are 195 degree and in
the absence of the fan override or chassis air being on the water temperature
gauge should cycle between 200 and 190 degrees.
The hydraulics of the fan partially bypass when in idle mode and full on in high
mode. The reservoir is the big black tank on the road side of the engine bay. It
is also the reservoir for the power steering system. Don't forget it has three
filters inside.
I changed my Alarmstat to 190 degrees and run lower temperatures now. It is
manufactured by Medallion Instruments and is available from BB. It is located in
the water jacket near the water pump adjacent to the water temp sender. It has
two wires.
I have an electrical drawing for the fan circuit for a 1990. I imagine all
would be the same since I doubt BB reinvented the system each year. I do not
have a schematic of the valve.
Leroy Eckert
1990 WB-40"Smoke N Mirrors"
Niceville, FL
Royale Conversion
----- Original Message -----
From: Rick A.
To: WanderlodgeForum@yahoogroups.com
Sent: Sunday, August 05, 2007 9:11 PM
Subject: [WanderlodgeForum] PT Engine Cooling Fan System


Has anyone figured out how the PT engine cooling fan system actually changes
from low
speed to high? Obviously there is a fan override switch on the dash and a
temperature
controlled switch on the engine which when activated turns the fan on high.
Question is,
what do they really turn on? or off?

thanks,
Rick Archie
85PT40
Fort Worth





[Non-text portions of this message have been removed]