This is probably because of modern fuel additives & the introduction of ethanol into fuel. Repair Kit for a eight cylinder alloy Bosch. This Repair Kit is suitable for the following Bosch Fuel Distributors numbers.
0438101017 Repair Kit for Bosch Fuel Distributor Mercedes 420SEL 500SL 560SEL
Vacuum Pump Repair Seal 6422300065 Repair Kit For Mercedes OM642 3.0L LA1231061
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Vacuum Pump Repair Seal 6422300065 Repair Kit For Mercedes OM642 3.0L US
Engine Timing Chain Kit Cam Phaser Repair Kit For Ford Expedition F-150 5.4L 3V
