In short yes, I have several of these kits!
Caveats;- It does work!-A strong yes but with qualifications!
The issue isn't the tool its the circumstances and the operator!
Much more difficult with the OM612 due to manifolding!
Available to space at the back of the head makes it more difficult to do the job!
So going back here, the tool will work quite well if the glow plug was a quality unit. In many cases a cheap glow plug was installed which eventually (swollen up in the head) and broke off upon removal attempts. The material body is often "soft" and though it will take a tap cut of 5 x 1,00mm (supplied in the kit) the extraction adapter fails when the puller mandrel is exerting the extraction force ripping out the threads.
The drilling guide mandrel is very good at centering itself in the head recess! In some cases however its too long which limits what size of hand drill you can use.
The results is that you go drilling it off centre taking out the head threads and "going oval"!
The other issue maybe more serious is that the glow plug is coming apart inside AND by you drilling into it the tip drops of and falls in the head. Don't laugh it has happened to me!
Then its a definite head off!
Hence I have made a dummie injector to blast the cylinder full with shop line pressure as a precaution!
In any case you may have to install a helicoils or a timesert (my preferred method ) to recover the threaded portion of the head once the old glow is out!
To sum up the tool is better suited for use with engine out of the vehicle. And I have dripped the engine in the frame to gain access to the back "glow"!
I sometime abandoned the the tool and use a simple angle air drill and cut the body out with an aircraft precision drill & home made guide being about 8" long--Jobber lengths won't do it for the most part!
Much of this work boils down to
judgement calls!
An hour per glow maybe two tops should do it, especially if a customer is paying shop time to extract the glow.
On the 612 the manifold may have to come off --a 11 hour jobbie by itself!
In these cases a 15 hour job will cover the head off plus parts (cheap) and a spark erosion machine & head job exercise.
Its machining work basically something that is an integral part of motor vehicle construction but not taught these days in MV Tech schools sadly!
Now a word on what some have called a Sprinter Specialist and broke them.
I will often scratch my head on this side of the pond at American s reverence of thing German ALL HAIL CAESAR--
KAISER !
This permeates all the way down to an American mechanic who changes his name to Stefan from plain old Steve! Then put a shingle out with "WERKS and "TEKNIC" somewhere in his handle and claims he is German. When really his third maternal great grandmother came over in an immigrant boat from Silesia!
On the other side of the pond this would proffer a chance for Brits to poke fun and take the pi$$ so beware! Like doing a John Cleese act from Farty Towers!
Look buyer beware here, and you might be better off and in more caring hands giving your Sprinter to two good ol' Buds machinists --biker dudes at Bubba's garage!
Sorry to be a bit cynical in this area but I don't tolerate impersonators too well or Con-men for that matter!
Neither so I like people who call themselves Mechanics and Techs when they are not ualified be be so! A bit like saying you are a Doctor or a Dentist when you ain't! But merely a Physicians Assistant
All the best
Dennis