Running in of MAN DG

Hello everyone
Next week I will be able to run my 6L32/40 MAN diesel engine 3000KW after 2 weeks of overhauling in Marseille, France. This includes cylinder head, cylinder liner, piston, replacing of bearing shell of connecting rod and of cranckshaft. I will absolutely follow the constructor instructions in MAN manuel, but I would like to know if there are any general special recommendations that I should pay attention to during the running in and after it.
Thank you.

I can’t remember how detailed the MAN run-in is with regards to slow start and manually bringing up to rated speed incrementally. But off the top of my head:

  • The obvious checks - Personally double and triple check the crankcase and sump for tools, rags, debris, flashlights, etc.

  • Close flashlight inspection for JW leaks around the cylinder heads. Specifically, know ahead of time where the cylinder liner tell tale leak holes are located - they are small holes usually just under the bottom of the head or at the bottom of the head and should be identified on the head/liner drawings in the manual. Depending on which hole leaks will tell you what isn’t seated properly.

  • Watch oil pressure, JW head tank level (Mark the level, if it drops find out where its going!) , and absolutely watch bearing temps very carefully

  • If you have an OMD or splash oil monitor, and it goes off, trust it, investigate it, verify it.

  • Likely after a short run is a stop to re-torque the con-rod big end bearing bolts (this is very important), and possibly also check hot web deflection (protect your wrists/fore-arms, its Hot!).

  • With heads being replaced keep an eye on exhaust temps. New injectors don’t always mean properly set injectors. And really any time you replace injectors on those things you should be checking for high pressure leak off/bad seal on the high pressure pipes. And obviously valve lash might need re-adjusting as well.

I worked on the V version of the 32/40s for many years. I definitely had one head leak but we caught it from the weep hole before running and it was quick easy head pull to replace a damaged o-ring. Also, I don’t care how experienced the people I’m working with are, even if they have decades more than I do, I won’t sleep well if I don’t check the crankcase myself too.


Follow the MAN running in procedure as well as taking thermo imaging camera (see to scan the bearing temps on start up -stop if any anomalies.

I bought a phone with a built in FLIR camera just for these kinds of situations

Which bearings might they be? By the time a hot spot shows up on the outside of the engine at startup the damage is long since complete, probably including a close up view of an explosion door or two.

MAN start up procedures are roughly as follows:
Run engine (no load) 30 secs, stop CC doors off feel bottom end and main brgs for temp. CC doors on
Run engine for 2 mins, stop and repeat above…
Run engine for 5 mins , stop and repeat…
Run engine 10 mins, stop and repeat…

Using a thermal imaging camera can speed up the bearing temp as it can capture all temperature in view and on the Fluke ones gives you the highest and lowest temps in shot

Ah so … that will work.

I use a Fluke regularly and have found issues that might not have been discovered until damage occurred much later. Mine has the video feature as well which is great for reviewing a quick survey. The Fluke software is great for detailed inspection and report writing.

Agree, Fluke connect can make a quick and simple report.