Clipper, Cummins CT8.3, Thermostat, Land Yach

[masseyfarm]

Applies specifically to the Clipper but may apply to other units with the CT 8.3.
On local test runs up to 30 miles after winter storage, I found the Clipper's 8.3 Cummins was not warming up like it should. Even though we only have 80000 miles on the engine I thought it best to change out the thermostats before heading out for another hot summer season. A little preventive maintenance usually goes a long way in boosting confidence and eliminating problems.
To replace the twin thermostats on the Cummins CT 8.3 requires first a good fluorescent work lamp to keep the shadows to a minimum, both metric and standard sockets of 1/4 - 3/8 and 1/2" drive, and wrenches. A good capacity catch tray for the antifreeze, and a funnel with a screen, and at least 2 X 3 US gallon containers for the drained coolant.


ANTIFREEZE IS TOXIC TO YOUR PETS SO WASH DOWN ANY SPILLAGE WITH AMPLE WATER TO FLUSH IT INTO AN AREA THAT IT WILL NOT POOL.
Recycle your anitfreeze where you buy you new antifreeze. Never dump in the storm drain or watershed.


Shut the manual hot heater line valve and open the drain cock and return heater line valve. Crack the rad cap, and take 6 gallons of coolant out. When you crack the filter, there should now be no coolant at this level. My unit still has the ABS/plastic shut off on the water filter and it is seized closed so I did not want to update it at this time. I thought I could possible free it up when the housing was off.


A combo open/box end 3/4" wrench for the bottom pivot on the alternator, small and large flat screw driver, small ball-peen hammer, pry bar, vice grips, slip pliers, wire brush, putty knife. anti-seize, lots of wipe rags and something comfortable in the way of a mat to sit on while in the engine compartment. I also take 2 or 3 buckets (ice cream buckets or similar) to store bolts etc in while in the engine bay. Also I put down some plastic on the carpets as you will be in and out of the motor home a number of times and you don't want to create more work.

There are 2 small thermostats.They are located in the housing under the upper radiator hose housing. Yes, that means removing the top hose housing and the casting that everything is bolted to under that. You will see the thermostats when you get the top rad housing off, but to get to them you will have to remove -
the belt idler, the top two bolts on the alternator to swing it over on the lower pivot, the upper rad hose and 90* casting 2 bolts, the water filter, the small 5/16 vent line into the water filter casting. Then the 2 bolts holding the casting over the thermostats. And you are there. Swing the thermostat casting up onto the head to clean.
I took this opportunity to change the 90* top hose and the water filter with additive, as well as the thermostats and gaskets. Some operators might want to change the water pump now as you have access, but I did not feel it was needed at this point on mine.
Now you just have to clean up the casting face on all items and install your new thermostats and gaskets and put everything back together in reverse order.

The 2 thermostats are 181* and # 3928639.

Be sure to also clean the face for the belt idler as if it is out of alignment your belt will not last.

Top off with new antifreeze and run the engine and check for leaks. Recheck that you have heat at the front heater and shut down and top off the rad again when it cools.

Its not a nice job but again it is rewarding when you have been successful and know exactly what has been done.

Now you have saved enough money on this to job to buy another diamond for that great lady in your life.
Sorry no pictures today as she has gone to get the diamond.
Dave

[John H.]

Dave, Thank you for the helpful tips.

Keep them coming

[masseyfarm]

Some final information to finish off this thermostat install on the Cummins CT 8.3.

The coolant shut off valve on the water filter housing was seized but I was able to free it up once I had the casting off. Sprayed with silicon spray and let sit overnight. Works good now. I will add that to the maintenance cycle to spray the top with silicone to keep the elements from penetrating from the exposed top side.

The gaskets (2) are Cummins #3060912 with six bolt holes and #3914310 with 2 bolt holes.

The thermostats (2) are as mentioned Cummins #3928639

The 90* top hose was not available locally so I substituted one that was close and shortened it to fit. I used Volvo # .20999978.

I did not change the water pump as when I checked it with the belts off, there was no indication of wear/slack or other problem.

The belt was new last year and was in good condition so I reinstalled it. I do carry a spare belt in the basement parts chest.

Total cash outlay was less than $150.00 without the antifreeze that I had in my stock.

T GW got back from her shopping trip and we have the pictures.

Picture 1: original thermostats before removal. 2: thermostat upper casting turned upside down to clean, thermostats below in block. 3: original thermostats with water pump pulley, 4: thermostat upper casting cleaned. 5: block before cleaning. 6: all clean. 7: This face of casting is where the belt tension idler mounts. Be sure it is clean also. 8: The engine bay on the Clipper with mats for comfort. 9: installing new. 10: Job done.
Dave

[John H.]

Dave, did A.S. use the CT8.3E ?

[masseyfarm]

Not sure about the electronic version but I believe it was available in 1997: The CT were first supplied with the Oshkosh HD raised rail chassis and when Freightliner completed the takeover of the Oshkosh chassis division in Jan. 1996 they continued to use the 8.3 until they changed to the cheaper and heavier Cat. sometime in 1998. Cat was trying to push their mid size highway engines at that point and Cummins was having fuel pressure problems with the new electronic version of the 8.3.
They are great engines and are an enlarged version of the 5.9 and share many parts.
Cummins C Series engine - Wikipedia, the free encyclopedia
Dave

Originally Posted by John Haggard

Dave, did A.S. use the CT8.3E ?

[masseyfarm]

I am asked frequently how access is gained to the engine on the Clipper.

The Clipper (and other Airstream Class A Diesel pusher series) are equipped with rear mounted radiators and have limited access to the engine compartment from the outside. (SOB models are equipped with side mount radiators and have better access from the rear. This is at the expense of the additional large side storage bay that an AIRSTREAM offers.)


To access the engine for servicing the drive belts or any other engine mounted accessories, one must enter the engine bay from below the bed.

The bed and storage compartment box below the bed have gas assist struts to make it easier to lift and to keep the area open while in the engine bay. There is also a safety prop that should be used to secure the overhead in the upright position so that you are not surprised if a gas strut should fail.


The bed frame may be lifted by first pulling the mattress and bedding forward about 12-14" and this will allow the bed frame/mattress/pillows to pivot at the hinge and clear of the rear wall.

If there is a major repair planned, it is probably better to remove the bedding and stand the mattress up against the passenger side wall, or remove it from the area to give better access to the work area.


In the picture below, the mattress has been stood up against the passenger sidewall and access can be gained from the other two sides of the coffin.




The air cleaner, fuel filter/water separator, are accessed from the rr side compartment, along with the Power Gear hydraulic jacking reservoir. It is also possible to reach the fuel pump on the Cummins from here if it is necessary to reach the solenoid shut-off to shut the engine down for some reason.

Airstream had better access to the engine bay in these early models as in the later models the box access seemed to get smaller with each design change.

SOB's had access thru the wardrobe closet located at the rear wall of the coach and I can imagine the pain of removing everything hidden in there before handling any repair tools.

Dave

[masseyfarm]

I stand corrected once again. It's hard to believe Airstream ever made two units the same.


I said Airstream pushers had rear mounted rads. Well, that only applies to the Freightliner chassis, as the Spartan Chassis did come with a side mounted rad option and the LEGACY diesel pusher in 1993 used this chassis.

• Dual Roof AC
• Spartan Chassis
• LP Generator
• Skylight above Tub
• Walk-Thru Bath
• AM/FM/CD/Cassette Stereo
• Swivel Chair
• Convection/Microwave Oven
• Jackknife Sofa
• Booth Dinette
• Double door refrigerator
• TV
• 3 BURNER STOVE
• REAR HITCH
• REAR VISION CAMERA
• Day/night shades
• Front Living Room
• Fiberglass Exterior
• Rear Queen Bed
• Gas Water Heater
• Center Kitchen
• Rear Ladder
• Patio Awning
• Motor Home Jacks
• Class A Diesel - 1993 - Airstream Airstream - Fort Myers, FL - FTM1261D - RV Sales - Camping World

QUOTE=masseyfarm;1135401]
The Clipper (and other Airstream Class A Diesel pusher series) are equipped with rear mounted radiators and have limited access to the engine compartment from the outside. (SOB models are equipped with side mount radiators and have better access from the rear. This is at the expense of the additional large side storage bay that an AIRSTREAM offers.)"

[xrvr]

The MH in FT MYers--what diesel engine would it have? My wife would kill me If I even mentioned it to her. jim

[xrvr]

I looked it up---cummins with allison. jim

[masseyfarm]

I am pretty much caught up on my maintenance on the Clipper so I find myself looking for preventive stuff to do now.

I was in the engine bay with my silicone spray can, and checking things over, when I spotted a potential problem near the exhaust elbow.(this is right at the exhaust brake valve and tends to hold a lot of heat once warmed up )

Some of the heavy electrical cables, running to the Heart Inverter, were hanging a bit close by the exhaust elbow.

I tied those up with the plastic ties, and then thought maybe there would be a long term benefit it I installed a heat shield in this area.

Given our current weather it is not a problem but our next mountain tour will be middle of August, with the trailer, over Kootenay Pass, highway #3 Salmo-Creston.
Kootenay Pass - Wikipedia, the free encyclopedia
There are some brutally long pulls on there in the August heat and the last thing you want to do is have a shut down in that situation. (even the fridge would fry if you get immobilized on that type of grade )
http://www.th.gov.bc.ca/popular-topi...de-profile.pdf

The heat shield is a piece of perforated aluminum that should do a good job protecting the wire bundle.

Dave

[masseyfarm]

While tying up the previous task, I stepped back to admire my work and asked myself " why do I need a heavy piece of 3/4 EMT to act as a safety prop for my bed in the up position?".

The total supported weight on the prop is approx. 30lbs, and even if the gas struts failed, there would not be that much stress on the prop.

I would have thought AIRSTREAM could have supplied this in aluminium.

The EMT 3/4 pipe weighed 870 gms = 1.9 lbs.


I replaced this with a nice finished aluminium handle off a discarded broom that weighs 220gms=.49lbs.

So I am now 1.41lbs lighter on the back end.

Now if I keep buying light beer I will soon have to take on ballast to keep the Clipper on the road.

Dave

[masseyfarm]

When I read these horror stories of engine access on SOB's, I appreciate the relatively easy large access the Clipper has to the engine bay.

" We will try the closet thing tonight since the floor between the closet and the bed seems pretty unaccessable, we tried to slide it out for an hour or so. I will keep you posted when we finally find the engine access. Seems pretty scary that in 41k miles, no one ever opened the engine compartment...."
"4 screws in closet floor, should get you to the alternator. Slide out, bed frame has latches, release and remove then more screws in floor gets another floor piece out to access top of motor. Good luck."

The NS rear bed mount on the Airstream Clipper is simple, practical and allows full access to the engine bay for major or minor service requirements.

The designers of some of these SOB's use the same layout for Pushers and Freds.

Here is a FW Expedition floor plan. No access for the engine top on this that I can see without removing the sink? I presume you crawl in over the engine from the rear to repair that leaking fuel line ???????

Originally Posted by masseyfarm

I am asked frequently how access is gained to the engine on the Clipper.Dave