A6420700587 — Frequently Asked Questions
Verified answers about the Bosch A6420700587 (0445115027) Mercedes OM642 3.0 V6 CDI Piezo Injector.
What is Bosch A6420700587?
It is the Mercedes OE reference for a Bosch piezo common-rail injector on the OM642 3.0 V6 CDI engine; the Bosch numbers are 0445115027 and 0445115064.
Which vehicles use this injector?
OM642-engined Mercedes C/E/S-Class, ML/GL, Sprinter and Viano, plus Chrysler 300C 3.0 CRD and Jeep Grand Cherokee/Commander 3.0 CRD.
Is it a piezo or solenoid injector?
It is a piezoelectric injector and needs a Bosch piezo-capable test bench.
What is 'black death' on the OM642?
Hard black carbon build-up around the injector base caused by combustion gases leaking past a failed copper seal; it can seize the injector in the head.
What are the Bosch numbers for A6420700587?
0445115027 and 0445115064 (0445115063 is a related alternate).
Do I need to code the injector after fitting?
Yes - injector quantity/coding must be programmed into the CDI control unit with Mercedes diagnostics.
What are the symptoms of a failing OM642 injector?
Hard starting, rough idle/misfire, smoke, loss of power, higher fuel use and black carbon around the injector base.
Why is my injector seized in the head?
Years of 'black death' carbon lock it into the bore. Use a dedicated puller; do not lever against the head.
Why renew the copper seal and hold-down bolt?
Both are one-use items; reusing them risks blow-by and the carbon build-up that damages the injector and head.
Should I change one or all six?
Diagnose each with live correction values and a bench test; on high-mileage OM642 engines it is common to renew a full set.
Can a leaking injector damage the engine?
Yes - persistent blow-by and soot contamination can damage the bore and contribute to wider running problems.
Does a remanufactured A6420700587 perform like new?
A properly remanufactured piezo injector is bench-tested and recalibrated to the Bosch plan to meet original delivery and back-leakage specs.