MI18-21A

MAINTENANCE
INFORMATION
DATE :
SUBJECT :
REVISION : A
MI18-21A
May 2018
SECTION : 22 HVAC
BITZER A/C COMPRESSOR OIL CHANGE INTERVALS
THIS REVISION SUPERSEDES THE PREVIOUS VERSION.
Images added for the evaluation of the oil condition
07-09-2018
IMPORTANT NOTICE
This preventive maintenance is recommended by Prevost to increase your vehicle's performance. Note
that no reimbursement will be awarded for carrying out this modification.
APPLICATION
Model
VIN
ALL VEHICLES EQUIPPED WITH THE BITZER A/C COMPRESSOR
DESCRIPTION
Change the Bitzer A/C compressor oil according to the following maintenance schedule extract.
At the same time, clean the oil filter/strainer and the magnetic drain plug.
BITZER COMPRESSOR MAINTENANCE SCHEDULE
DESCRIPTION
INTERVAL
Drain the shaft seal oil collection tube
1 month
Check the oil color and the oil level, top up as needed. Change the oil if it has
darkened (see oil evaluation criteria in this document)
12 months
Change the oil, clean the filter/strainer and the magnetic drain plug
36 months
Writer: EL

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For complete information on Bitzer A/C compressor maintenance, installation, torque chart,
approved oils, refer to the following Bitzer manuals found on your Technical Publications USB
flash drive and on the Prevost Technical Publications web site.
•
•
•
•
•
Bitzer kw-540-1 Maintenance Instruction
Bitzer kb-540-3 Operating Instructions
Bitzer kw-541-2 Exchanging Shaft Seal
Bitzer kw-555-3 Tightening Torques
Bitzer kt-510-5 Tech Info oils
Also: Prevost Maintenance Information MI18-37: LANG KK73.1 Electromagnetic Clutch Removal &
Installation
DANGER
Park vehicle safely, apply parking brake, stop the engine. Prior to working on the vehicle, set the
ignition switch to the OFF position and trip the main circuit breakers equipped with a trip button. On
Commuter type vehicles, set the battery master switch (master cut-out) to the OFF position.
SHAFT SEAL OIL COLLECTION TUBE DRAIN
The shaft seal oil collection tube (Figure 1) collects oil which seeps past the shaft seal. Remove
the tube plug and drain the oil into a container for disposal. Put the cap back on the tube and
place the tube into the clip bracket.
FIGURE 1: SHAFT SEAL OIL COLLECTION TUBE
OIL COLOR AND LEVEL CHECK
1. Run the compressor for at least 15 minutes, the time required so that the oil gets clear,
unclouded and stabilized (without bubbles).
2. Check the oil level during operation. The proper level is:
R.H. sight glass: between ½ and ¾ of sight glass height.
L.H. sight glass: the full sight glass height.
Writer: EL

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Figure 2: L.H. SIGHT GLASS
Figure 3: R.H. SIGHT GLASS
The oil level is expected to remain the same over time except if there is a loss of refrigerant.
Adding oil must be done by taking the same precautions as when changing oil in order not to
introduce the moisture content of the ambient air in the air-conditioning system.
3. Check for discoloration of the oil. It should be clear and light in color. Darkened, cloudy and
contaminated oil must be changed. Diagnose the problem. See the following images to
help you evaluate the state of the compressor oil.
Tip: use the reflection of light on the
threads to determine the color of the
oil.
Writer: EL

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OIL EVALUATION CRITERIA
Normal
Shows deterioration
Must be changed at once
Heavily deteriorated
compressor has suffered
damage due to this oil
Should be changed soon
COMPRESSOR OIL CHANGE
1. Check the oil level first and note down.
2. Connect the refrigerant recovery station to the service connections of the shut-off valves.
3. Isolate the compressor from the system. To do so, frontseat the compressor shutoff valves
(Respect the prescribed torques. Refer to Figure 4 & Figure 5 for proper torque values).
4. Extract the refrigerant using the recovery station until ambient pressure is reached. Take note
of the quantity removed.
5. Remove the magnetic drain plug (Figure 7).
2- Compressor shutoff valve frontseat position.
Torque: 21 lb-ft (28 Nm) max.
4- Remote pressure transducer connection. Always
under compressor pressure.
FIGURE 4: COMPRESSOR SHUTOFF VALVE IN FRONT
SEATED POSITION
Writer: EL

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2- Compressor shutoff valve backseat position.
Torque: 12 lb-ft (16 Nm) max.
3- Service port 7/16”-20 UNF. Isolated when the
stem is completely out (fully back seated position).
Front seat 2 turns for service gage reading.
Torque: 7.5 lbf-ft (10 Nm) max.
FIGURE 5: COMPRESSOR SHUTOFF VALVE BACK
SEATED POSITION (NORMAL OPERATING POSITION)
FIGURE 6
A: OIL FILL PLUG (torque 15-17 lb-ft (20-23 Nm)
B: SIGHT GLASS
FIGURE
7:
CUTAWAY
VIEW
SHOWING
OIL
FILTER/STRAINER AND MAGNETIC DRAIN PLUG. TORQUE
37-52 LB-FT (50-71 NM)
SEALING PLUGS AND SCREWS – Torque specifications by type
1/8″-27 NPTF : 7.5-10 lb-ft (10-13 Nm)
1/4″-18 NPTF : 15-17 lb-ft (20-23 Nm)
M20X1.5 & M36X1.5 : 37-44 lb-ft (50-60 Nm)
Oil drain plug M22x1.5 : 37-52 lb-ft (50-70 NM)
6. Drain the oil into a container. Measure the quantity of oil removed.
7. Extract and clean the oil filter/strainer. Reinstall once done.
8. Clean the magnetic drain plug and reinstall (refer to Figure 7 for torque value).
9. Through the oil filling port, add the same amount of fresh oil. More oil should be added if the
oil level was too low when checked at the beginning (refer to Figure 6 for oil filling port plug
torque value).
10. Evacuate the compressor to 500 microns.
11. Charge the system with new refrigerant. Charge with the same quantity as recovered
previously.
Writer: EL

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Bitzer A/C compressor – oil specification
Oil type : Polyolester ISO68 for R134a
Such as :
•
Bitzer BSE55 (POE)
•
Castrol Icematic SW 68
•
Mobil EAL Arctic 68
•
Shell S4 FR-F 68, Clavus R68
For more details on oils, see Bitzer kt-510-5 Tech Info Oils available on the Prevost Technical
Publications web site.
PARTS / WASTE DISPOSAL
Discard according to applicable environmental regulations (Municipal/State[Prov.]/ Federal)
Access all our Service Bulletins on http://techpub.prevostcar.com/en/
Or scan the QR-Code with your smart phone
.
Are you a vehicle owner?
E-mail us at [email protected] and type “ADD” in the subject to
receive warranty bulletins applicable to your vehicle(s) by e-mail.
Writer: EL