* No. That's the short answer. Unless you have knocking or leakage, I wouldn't recommend any "preventive" maintenance on the prechambers.
* You can, with some extra effort, remove and check prechambers when you're spray-testing/replacing the injectors. But generally the prechambers aren't even disturbed during injector replacement unless there's a specific engine symptom. Be sure to use new seal (crush) rings if you take the pcs out.
* If you've got some time and some money, at the same time (and, if your life is anything like mine, who knows when the next time will come for that) and want to do some serious preventive maintenance (I'm assuming that the engine is running ok with no specific problem symptoms), go ahead and replace the injector nozzles (or just buy a set of rebuilt injectors) and replace the glow plugs as well.
* Of course, it's understood that, given the time and money, your diesel maintenance routine should be in this order. Both fuel filters, air filter, engine oil and filter. With the valve cover off, check the cam timing. Just eyeball the timing marks; line up the cam marks and read the crank degrees. No need to use a dial indicator on the intake event, etc. Chain stretch is an issue on high mileage engines. If you're more than 3 or 4 crank degrees retarded, think about replacing the timing chain (and tensioner). This should restore the pump timing, if it was correct in the first place. Then go on to the glow plugs and injectors. This would be a good time to do a cylinder leakage test and a dry compression test (a set of baseline numbers for future comparison).
* Then on to some peripheral issues that regulate shifts (maximize power) and release dragging brakes (that sap power) and you've got a happy diesel.

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ASE Master Tech
Quality Enterprises
Mercedes Svc. & Restoration
Sheridan, IN
317.769.3536