From what I've read on the M/B diesels they use stretch bolts. Like VW and probably every other engine of German origin. So, in this case YES I'm most certain that you will need to use THAT tool again...at least once. On Vw diesels you torque the first time, run the engine till warm and then give all the bolts 1/2 turn with a breaker bar then run the car 1000km and give all the bolts ANOTHER 1/4 turn each in sequence. It is the last one that always gives me the willies. It's hard for me to drive a car 650 miles and then ( even though it's running fine) give all the head bolts another quarter turn. My heart is always in my throat, and I'm thinking...gee I sure hope quality control wasn't on coffee break when these bolts were made!!!!!!! I always felt much better with the "old style" Vw bolts, the ones that after 650 miles you would back them off and then actually re-torque them to spec. Ok, I've rambled on enough about my "stretch-bolt" phobia! Hope it goes well for you and you don't need to pull the pre-chambers, although it's NOT a bad idea to do so , even if it's just to de-carbon the things. ( the 'ol scrub-ola) Cheers! Tom