Wow, this is pretty loose. How many miles this has been on engine?
I have also read about bearings in those vacuum pumps, another failure point, somewhere there was even suggestion to mount magnets beneath the pump housing to catch the balls.
Well, somewhat going off the rails but as OM617 turbos are hot topics currently…
When I took my two vacuum pumps apart, both had solid bearings and bushings, I thought long about replacing the bearings for one going to engine but didn’t chase it.
Eventually those old motors will fail one way or another, reasonable preventative maintenance is essential and also okay occasionally to poke some things deeper to catch something like above from happening but whether to rebuild those engines system by system or wholly… had I known what I know today (
) I would have gone for swap from newer donor (OM605/6 or even OM612/3).
My OM617 story is that previous owner made the swap, then he drowned it on off-road competition, found another to replace and when he sold the vehicle I got the one with shorter rod as extra. The engine on car wasn’t great but moved the vehicle decently till one day half of second piston ditched the ride through cast iron wall. Mechanic said that out of five cylinders two were not working (as should), two were so-so, and one was good enough. We joked that this engine was from some taxi. Yet the G started on cold winters, saw some highway and fair bit of mud action. Also had no abnormal oil or fuel consumption, heavy smoke, noises or heating issues.
For those engines it is not the end of road for many years and miles when things are far from ideal.
Then two engines got rebuilt to one. Block and head work was done well: new pistons, chain, bearing, surfaces machined, crank grinded and balanced, valves lapped etc. And this part is still strong, after this rebuild engine has done roughly 45,000 km before whole vehicle went to ‘project’.
But for every accessory just best of two was chosen. And there lies the issues I am still dealing (what have been there since the engine rebuild and before). The IP was worn, they can be adjusted to certain degree but one point also need full rebuild; ok now I have a Bosch remanufactured pump, test guy was pretty impressed. Water pump housing leaked because corroded ends. Turbo worked but I was quite surprised when I took it apart, another thing needing full service. There were lot of oil leaks, some surfaces were damages from previous repair works, it just takes a small screwdriver mark to things not align up perfectly, on other places not right gasket were used. Some small bit and brackets missing. Turned out that oil filter had stuck valve etc.
In the end, going over every system, replacing every gasket, seal, hose, bearing and bushing, machining and matching all surfaces etc., this five figure Metric Motors offer in other OM617 rebuild topic seems reasonable price. But as those engines get older, some parts become unavailable: like valves in those vacuum pumps, or turbo parts. Least now the pistons are back. And option not going over every system means that something will fail one point. Last new cars with those engines were produced over 30 years ago.
Now, in this part of world, with 1000-1500€ it is possible to find Mercedes car with 130 or 145 KW diesel engine what might need a serious service but not every system rebuild. And it is good for many more rounds around planet. With this, keeping, meticulously maintaining and rebuilding OM617s does not make much sense, even with issues arising with swap. Of course I will drive and keep mine in order till it lasts but preserving history is for museums.
Still on frame and under deep cover of oil:
As it waits to put back on frame and all accessories attached: