Turbocharger - Updated Compressor Housing
86MERCEDES01TO: OUR MERCEDES-BENZ PASSENGER CAR DEALERS
DATE: May 1986 REF.NO. MBNA 09/5
SUBJECT: WARRANTY REPAIR ON GARRETT TURBOCHARGER (ALL ENGINES TYPE OM 617 A)
In the past, turbochargers have been submitted to us with accompanying warranty claims stating "Turbo noisy - exchange turbo". This statement is not sufficient and could result in a warranty rejection by the manufacturer.
Effective immediately, the procedure below should be followed to identify the source of noise as being in the
a) Rotating Assembly or
b) Air Recirculating Valve
Please note that due to its high operating speed of more than 100,000 rpm a silent turbo operation is not possible.
Test Procedure:
1. To verify the customer's complaint, test drive the car with changing loads at varying speeds.
2. Disconnect the vacuum line to the air recirculating valve and repeat the test drive.
a. If whistling noise is still noticeable, it is due to an unbalanced or damaged rotating assembly. Replace the turbo and submit it with a warranty claim stating: "Noisy Rotating Assembly".
b. If whistling is not noticeable, it is due to a noisy air recirculating valve. Replace only the compressor housing with a modified version having a 0.125" diameter rollpin in the air duct leading to the air recirculating valve. For detailed work procedure, refer to our Service Information MBNA 09/4. Return the removed housing (without pin) as quickly as possible to our Warranty Inspection Department with a warranty claim stating:
"Noisy Air Recirculating Valve".