Temps

[Mike McMahan]

I'm fixing to take my first hot weather trip(to Denver) in our 96 42'
Wanderlodge series 60 six speed towing my 28' race car trailer. My 89
PT 40 always stayed in normal operating temps on this trip. My owners
manual says normal engine operating temp 190 to 210. I can't find any
temps listed as high for the trans or retarder only a reference to a
high temp light that will come on at some point. Does anyone know what
is the high temp spec for these. Also at what temp does the cooling
fans on the trans cooler activate? Thanks, Mike McMahan 96 42'
Wanderlodge

[Pete Masterson]

The DD Series 60 has an exhaust "jake brake" retarder. It does not have a separate heat range and does not overheat. -- Indeed, the jake brake might actually have a modest cooling effect on the engine. The older 8v92 was a 2-cycle engine and did not have much compression braking, so other types of retarders were used, often one that was electrical technology -- that could be overheated and damaged.

Water temperature should be in a range of 180 to 210. Be sure your radiator is not clogged with oily dirt (it's not uncommon and it's difficult to see. The dirt accumulates around the edges of the radiator outside the area swept by the fan.) I replaced my radiator core and discovered a completely clogged radiator around the edges when it was removed. I now take off the grill, spray simple green and hose out the radiator (careful, don't use a pressure washer as you can bend the fins). It's best to have the engine luke warm (when you do this) -- warm but no sizzle sounds. I have the whole engine area steam cleaned every couple of years.

Engine oil temperature theoretically has a range of 200 to 250 degrees. Personally, I've seen 230 on a few occasions (one while going eastbound on I-70 on the grade approaching Aspen, CO). I prefer to pull to the side and let the engine oil cool down when it gets up that hot. Only takes 3 or 4 minutes.

The transmission seems to stay at 170-180 regardless. I've never seen it get any higher. The transmission cooler is in the bottom of the water radiator. The other radiator you see is not the transmission cooler. (I don't think it even has a fan.) The air flow through the transmission cooler is from the main radiator fan. I think it comes on at 190 or so ... or whenever you turn on the "fan override" switch or turn on the dash AC.

Enjoy your trip -- I've been to Denver many times by many routes....

Pete Masterson

'95 Blue Bird Wanderlodge WBDA 42

El Sobrante CA

"aeonix1@mac.com"

On Jun 16, 2008, at 8:12 PM, Mike McMahan wrote:

I'm fixing to take my first hot weather trip(to Denver) in our 96 42' 

Wanderlodge series 60 six speed towing my 28' race car trailer. My 89 

PT 40 always stayed in normal operating temps on this trip.  My owners 

manual says normal engine operating temp 190 to 210.  I can't find any 

temps listed as high for the trans or retarder only a reference to a 

high temp light that will come on at some point.  Does anyone know what 

is the high temp spec for these.  Also at what temp does the cooling 

fans on the trans cooler activate?   Thanks, Mike McMahan 96 42' 

Wanderlodge

[Don Bradner]

Assuming you are talking an Allison HT755 with transmission retarder, the max
temp for the transmission retarder is 330.

I do not have a separate fan for the trans cooler; assuming you are talking
about the main fan, the standard thermostat will cycle it on at 195 and off at
190, with an effective coolant range of 189 to 197 (because of overshoot).

I now have accumulated a modest amount of experience with downhill driving, and
some techniques for keeping speed under control. It is very common to find long
5 and 6% grades in the west (many miles long) and usually shorter segments of 7%
or rarely 8%.

I find that, at 6%, I could put it in 4th with the retarder on and run down at
constant speed (around 60) without a problem EXCEPT it would overheat fairly
soon. So, I use 3rd, and take it slower. In third gear the bus will decelerate
with the retarder on, and accelerate with the retarder off. I use the "enabled"
switch position so that I'm turning the retarder on with slight brake pedal
application. I apply the brake/retarder at 2100RPM and release at 1800RPM,
roughly 49 and 42MPH respectively.

In this process I turn the fan override on, as it would otherwise typically not
come on going downhill. In 100 degree ambient temperatures, the retarder reaches
roughly 300 at the point where I release it, and drops back to about 260. If you
get a stretch where the road has less grade and you aren't using the retarder
its temp drops very rapidly.

I've run 6% grades of 4 miles or more several times with this technique
(example: I-17 northbound into Camp Verde). I think the hill could be infinitely
long and the technique would hold up indefinitely.

Don Bradner
90 PT40 "Blue Thunder"
Eureka, CA

On 6/17/2008 at 3:12 AM Mike McMahan wrote:

>I'm fixing to take my first hot weather trip(to Denver) in our 96 42'
>Wanderlodge series 60 six speed towing my 28' race car trailer. My 89
>PT 40 always stayed in normal operating temps on this trip. My owners
>manual says normal engine operating temp 190 to 210. I can't find any
>temps listed as high for the trans or retarder only a reference to a
>high temp light that will come on at some point. Does anyone know what
>is the high temp spec for these. Also at what temp does the cooling
>fans on the trans cooler activate? Thanks, Mike McMahan 96 42'
>Wanderlodge

[Don Bradner]

You know, I read the "89 PT40" part of this and based my answer entirely on it,
somehow missing the multiple 96 references. That makes my reply, while accurate,
completely non-responsive. Sorry!

On 6/17/2008 at 3:12 AM Mike McMahan wrote:

>I'm fixing to take my first hot weather trip(to Denver) in our 96 42'
>Wanderlodge series 60 six speed towing my 28' race car trailer. My 89
>PT 40 always stayed in normal operating temps on this trip. My owners
>manual says normal engine operating temp 190 to 210. I can't find any
>temps listed as high for the trans or retarder only a reference to a
>high temp light that will come on at some point. Does anyone know what
>is the high temp spec for these. Also at what temp does the cooling
>fans on the trans cooler activate? Thanks, Mike McMahan 96 42'
>Wanderlodge

[Rob Robinson]

The old adage....."Go down hill in the gear that brought you up" might apply to some rigs, especially the heavier ones like BB, butnot for someyouSOBs monitoring this forum. Somelight-weight SOBswith 400+HP can scream up the hills in a much higher gear than the heavier rigs.You folks should never follow that old adage. Judicious use of your service brakes along with any brake assist (jake, exhaust, transmission brakeetc)you have is the answer. Alternate braking devices and take it easy on the way down. It does not matter if you weight 30 or 50K lbs gravity wins making going downhill an exercise in prudence

2008/6/17 David Brady <"dmb993@earthlink.net">:

Corey,

You probably know, but it's worth repeating: a good rule of thumb is
"don't go down faster than you can go up".

Regarding temps, you may want to invest in a VMSpc, or similar, so

that you can get data directly off the CANbus. Most of us have found
by now that our gauges aren't always accurate.

David Brady
'02 LXi, NC


Pete Masterson wrote:

The DD Series 60 has an exhaust "jake brake" retarder. It does not have a separate heat range and does not overheat. -- Indeed, the jake brake might actually have a modest cooling effect on the engine. The older 8v92 was a 2-cycle engine and did not have much compression braking, so other types of retarders were used, often one that was electrical technology -- that could be overheated and damaged.

--
Rob, Sue & Merlin Robinson

94 WLWB

[David Brady]

Corey,



You probably know, but it's worth repeating: a good rule of thumb is

"don't go down faster than you can go up".



Regarding temps, you may want to invest in a VMSpc, or similar, so

that you can get data directly off the CANbus. Most of us have found

by now that our gauges aren't always accurate.



David Brady

'02 LXi, NC





Pete Masterson wrote:

The DD Series 60 has an exhaust "jake brake" retarder. It does not
have a separate heat range and does not overheat. -- Indeed, the jake
brake might actually have a modest cooling effect on the engine. The
older 8v92 was a 2-cycle engine and did not have much compression
braking, so other types of retarders were used, often one that was
electrical technology -- that could be overheated and damaged.

[Glenn Allen]

Don,

Thanks for that non-responsive post. It was a good summary for us V92
owners that have not done much hill driving.

Glenn Allen
1986 PT-40
Marietta, GA

--- In WanderlodgeForum@yahoogroups.com, "Don Bradner"
wrote:
>
> You know, I read the "89 PT40" part of this and based my answer
entirely on it, somehow missing the multiple 96 references. That makes
my reply, while accurate, completely non-responsive. Sorry!
>

[Glenn Allen]

Pete,

Good Summary. Can you or someone elaborate on the following
questions I have about the areas of your post noted below relative
to a 1986 PT-40 6V92.

Thanks,

Glenn....(see questions noted below your comments):

> The transmission cooler is in the bottom of the
> water radiator. The other radiator you see is not the
> transmission cooler. (I don't think it even has a fan.) The air
> flow through the transmission cooler is from the main radiator
> fan.

1a) There is a small radiator attached on the outside bottom left of
the main radiator that has hoses running to the power stearing fluid
cannister. I assume this small radiator is cooling the fluid for
power stearing and the hydraulic fan. There is also a round
cannister down low that is between the driver's side of the engine
and the main radiator with large diameter (3"+) hoses from the
radiator and engine. There are also lines from the transmission.
I'm assuming this is the transmission heat exchanger. I would
assume water is flowing from the bottom of the radiator to the
transmission cooler and then to the engine. Is this correct?

1b)I notice on this transmission cooler there are plugs on each
end. Do these plugs drain the water or transmission fluid from the
heat exchanger (or maybe both)?

1c)Should this transmission cooler be cleaned or serviced?

> I think it comes on at 190 or so ... or whenever you turn on
> the "fan override" switch
> or turn on the dash AC.

2a) I believe my fan is "always on". When the engine temp is cool,
the AC is off, and the fan override is off, should the fan be
turning at idle speed or stationary?

2b) Is the speed of the fan proportional to the engine RPM?

3b) Where is the relay that the fan override switch controls?

Thanks for your insight.

Glenn Allen
1986 PT-40
Marietta, GA

[Pete Masterson]

===============================================

Pete Masterson, Author of

Book Design and Production: A Guide for Authors and Publishers

"Aeonix1@Mac.com"

Aeonix Publishing Group    http://www.aeonix.com

===============================================

On Jun 17, 2008, at 10:46 PM, Glenn Allen wrote:

Pete,

Good Summary.  Can you or someone elaborate on the following 

questions I have about the areas of your post noted below relative 

to a 1986 PT-40 6V92.

Thanks,

Glenn....(see questions noted below your comments):

The transmission cooler is in the bottom of the  

water radiator. The other radiator you see is not the 

transmission cooler. (I don't think it even has a fan.) The air   

flow through the transmission cooler is from the main radiator 

fan. 

1a) There is a small radiator attached on the outside bottom left of 

the main radiator that has hoses running to the power stearing fluid 

cannister.  I assume this small radiator is cooling the fluid for 

power stearing and the hydraulic fan.  There is also a round 

cannister down low that is between the driver's side of the engine 

and the main radiator with large diameter (3"+) hoses from the 

radiator and engine.  There are also lines from the transmission.  

I'm assuming this is the transmission heat exchanger.  I would 

assume water is flowing from the bottom of the radiator to the 

transmission cooler and then to the engine.  Is this correct?  

I'd have to go out to the coach and take a look. I don't recall the "canister" you mention (it might be there, but I don't recall it). The bottom (1/4 or so?) of the water radiator is a radiator for the transmission fluid. When my radiator core was removed, there was a 'stub' radiator for the transmission fluid. The new core attached above it. I no longer recall if water moved through some of the tubes and transmission fluid moved through the other tubes or exactly what the physical arrangement was. 

The second small radiator is for cooling the power steering (and may cool the hydraulic fan fluid as well). The power steering reservoir is a large canister on the curb side visible through both the rear and side doors. Do not overfill it. If you do, it will coat everything nearby with oil. (And I'm not going back to that place for service again.)

The fan pulls air through a 'stack' of radiators. You can remove the grill on the street side and you'll see (I'm going by memory here, so bear with me) the AC condenser, and the Air Charge cooler. Behind the air charge cooler is the regular water radiator with the transmission radiator in the bottom portion of it. You can't see the water/transmission radiator since it's fully covered by the Air Charge cooler. 

Looking from the inside, you mostly see the fan and the metal shroud that makes the fan more efficient.

1b)I notice on this transmission cooler there are plugs on each 

end.  Do these plugs drain the water or transmission fluid from the 

heat exchanger (or maybe both)?  

Afraid I don't know. I have a 400+ page DD Series 60 manual (as a PDF). Perhaps I can make a copy available to you if you'd like. (I bought a CD with it on eBay.) I don't know if this manual discusses the radiator set up in the coach (bus) as it's mostly focused on heavy truck installations. More likely this is covered in Allison documentation -- I don't have any of that stuff beyond the owner's manual.

1c)Should this transmission cooler be cleaned or serviced?

The transmission fluid filters should be changed every 36 or 48 months depending on the size of filters you have. (I have to check this.) These are located in the transmission 'pan'. When the filters are changed the transmission fluid is also changed. Use a synthetic transmission fluid (I have Transynd). I don't think there's any specific service required for the cooler itself. You change the transmission fluid on the same interval as the filters. With an RV you're going to probably "time out" rather than exceed the suggested miles.

Change the engine oil (and filters) every year or 15,000 miles, whichever comes first. A full oil change will take nearly 40 quarts (10 gallons) of oil. You can use a synthetic, if you wish, but the change interval is the same. I have Rotella or Delo for heavy duty diesel engines.

There is a canister on the curb side that holds about 3 gallons of oil and there's an automatic oil add system (requires air pressure to operate), if needed.

I think it comes on at 190 or so ... or whenever you turn on 

the "fan override" switch  

or turn on the dash AC.

2a) I believe my fan is "always on".  When the engine temp is cool, 

the AC is off, and the fan override is off, should the fan be 

turning at idle speed or stationary?

The fan should be not turning or turning very slowly at idle speed if the engine isn't fully warm. They fan will run at full speed if _either_ the "fan override" or AC switch (the little button on the automotive heat control panel) are on.

2b) Is the speed of the fan proportional to the engine RPM?

Not that I'm aware of. I think it has two or three speeds. Frankly, I've never paid much attention to the fan when it was operating. I've verified that it works and I've seen the clouds of dust it kicks up when it's on, though.

3b) Where is the relay that the fan override switch controls?

Front load center, SK 68 is the fuse. Relay K39 says "Chassis A/C Eng. Fan Enable" -- I don't see any other relay related to the Fan. I suppose that the fan override switch tickles the same relay as the AC switch.

There area two other main Load Centers. One is behind the cabinets above the dashboard (on the right). The cabinets have a false back that pulls out, revealing the TV aerial wires and a load center. There's also a load center in the rear closet on the street side behind a felt-covered door.

[putneyflash@...]

Not to butt in, But the Fan/steering pump is either a gear or vane pump and both depend on Rpm's to move oil, so there comes a point where you must have high rpm's to get the maxium flow to turn the hydraulic motor at its maxium, speed.

--
RE

-------------- Original message from "Glenn Allen" : --------------

Pete,

Good Summary. Can you or someone elaborate on the following
questions I have about the areas of your post noted below relative
to a 1986 PT-40 6V92.

Thanks,

Glenn....(see questions noted below your comments):

> The transmission cooler is in the bottom of the
> water radiator. The other radiator you see is not the
> transmission cooler. (I don't think it even has a fan.) The air
> flow through the transmission cooler is from the main radiator
> fan.

1a) There is a small radiator attached on the outside bottom left of
the main radiator that has hoses running to the power stearing fluid
cannister. I assume this small radiator is cooling the fluid for
power stearing and the hydraulic fan. There is also a round
cannister down low that is between the driver's side of the engine
and the main radiator with large diameter (3"+) hoses from the
radiator and engine. There are also lines from the transmission.
I'm assuming this is the transmission heat exchanger. I would
assume water is flowing from the bottom of the radiator to the
transmission cooler and then to the engine. Is this correct?

1b)I notice on this transmission cooler there are plugs on each
end. Do these plugs drain the water or transmission fluid from the
heat exchanger (or maybe both)?

1c)Should this transmission cooler be cleaned or serviced?

> I think it comes on at 190 or so ... or whenever you turn on
> the "fan override" switch
> or turn on the dash AC.

2a) I believe my fan is "always on". When the engine temp is cool,
the AC is off, and the fan override is off, should the fan be
turning at idle speed or stationary?

2b) Is the speed of the fan proportional to the engine RPM?

3b) Where is the relay that the fan override switch controls?

Thanks for your insight.

Glenn Allen
1986 PT-40
Mar
ietta, GA