Oil amount for MD22 / Prima M50

Herbert Lackner

after cleaning all diesel filters and before cleaning up the engine room I made an oil / filter change. This time I made sure that all the oil comes out, including the small amount at the bottom (1/4 liter) that the pump does not suck out. according to the engine data sheet the engine needs ~ 6 liters of oil, but when filling in 5 liters I am already above the "high mark" at the dipstick.  With previous oil changes I always thought that the rest of the oil will be somewhere inside the engine, at the bottom where the pump does not reach it. But this time I am pretty sure that all is out. I expected to fill in at least 5,5 liters,

I see the following possibilities:
1.) I have the wrong dipstick?  I have Perkins Part Number 3178E012 (it is printed on the stick).
2.) The data sheet is for the MD22/MD22L/TMD22, but I have the MD22A. Maybe the MD22A needs less oil (hurth gearbox...)...
3.) I would have to check the oil-level without inserting the dipstick complete (like for the gear-oil, but as far as I know the engine oil level has to be checked with the dipstick fully pressed in)

Can anyone with the same engine (Santorin) tell how much oil is needed for a complete oil change inlcuding filter or check what kind of dipstick is there (number, length)
any other ideas?

thx, herbert, SN120, Costa Rica

PS: diesel cleaning project is in progress. I think the water came in through the tank-vent while washing the boat. now all seems to be fine, test-run in waves tomorrow. interesting: the volvo water separator (first element the tank) did not filter out all water, the Racor filter (after the water separator) did that really efficent. Only a small amount of water found its way to the filter on the engine.

thx all for you recommendations and help. update will follow

Craig & Katherine Briggs

Hi Herb,
Although your post doesn't seem to mention it, let me assume you did run the engine after the first 5 or so liters so as to refill the oil filter, which takes, say, a half liter or so. Then you may have to add a bit more. Anyway, as a benchmark, I don't get a full 6 liters into my Perkins Prima M50 (same engine) when changing oil. Not to worry.

Also, the Hurth gearbox is totally separate from the engine oil, and, yes, you do put the engine dipstick all the way in. If after running the engine for a few minutes and then shutting it down you've got "Max" on the dipstick, it's Miller's time - relax with a cold one.

As to your water issue, the Volvo (and Perkins equivalent) water separator actually does not filter out any water - it just separates it and then, if there is an accumulation of water, a sensor in the bottom closes a switch and sounds (lights) an alarm telling you you've got water in that separator. If it does fill up it simply passes the water along to the filters - it is just an alarm that, if it works, gives you a chance to remove water before it gets to the filters. Not unusual for the sensor contacts not to activate with water in there, especially with our engines being as old as they are. Clean it out, clean the contacts, and give it another shot.

Cheers, Craig

Ian Park

I’m the same as Craig. Never get near 6 litres on an oil change.
The engine was developed as one of the first diesels for British Leyland cars - the Austin Montego. I have a Haynes manual for the car and it’s engine. Maybe the sump is shallower in the marine version?
I am not at home for a couple of weeks, but I’ll check what the car version says.



Hi Herbert,
On our Perkins M50 we would fill the oil filter as full as we could and take several minutes doing it to allow it to fully soak in.  EVEN after doing that and running the engine a few minutes (and topping off the oil) AFTER an hour or 2 of engine use we would need to add another pint of oil.  After my very first oil change I was concerned that the engine was using oil (it never did) but then saw no oil consumption.  This phenomenon occured after every oil change.

Goes without saying but if you pump the old oil directly into one of the oil jugs with a "site tube" feature on the side,  you can measure the exact amount of oil removed and have a very good idea of how much replacement oil is needed.

BTW, thanks for the tip on water ingress through the vent.

Bob and Suzanne, Previous Owner, Brittany de la Mer, SN 86
SM 429 Presently Saint-Pierre, Martinique

Gary Wells

If your MD22 setup is the same as mine, the heat exchanger is a long assembly runninh the length of the starboard side of the motor.  
Most of the heat exchanger is for cooling water, but the aft-most 6 inches is an oil cooler.  
While I'm not totally positive, I do believe a good amount of oil will stay residual in that oil cooler.  It would require disconnecting and bleeding a hose (or both hoses) circulating the oil through that cooler to get everything out.

Of course, your mileage may vary and I just know about my particular setup :)

Gary W.
SM #209, Adagio
Tortola, BVI

Craig & Katherine Briggs

Hi Gary,
The Perkins/Volvo equivalents are always confusing to me, but I thought the Perkins Prima M50, which Amel fit on some Santorins (including mine) was equivalent to the Volvo MD22, both of which rated 50 hp at 3000 rpm That's the MD22 I think Herb has on his Santorin. 

I had thought that Amel used the Perkins Prima M80 (a turbo M50) on (some of) the SM's for 80 hp and also the Volvo TDM22A turbo rated at 79hp.  There was also a Perkins Prima M60 at 60hp and a Volvo MD22 and MD22A rated at 59 hp at 4000 rpm (vs. 50hp at 3000).  Don't know if Amel used those.

Anyway, my M50 does not have an oil cooling section in the end of the heat exchanger, nor any oil hoses going to the heat exchanger, and I suspect Herb's is like that. All oil cooling is accomplished as the oil circulates inside of the block. My M50 also does not cool the ATF transmission oil.

Is your MD22 perhaps the 60hp version (also naturally aspirated), which could explain the oil cooler you describe? It still seems small for a SM, or is it the 79 hp TMD turbo?

Cheers, Craig

Gary Wells

Ah, Craig you are exactly right.  I actually have a TMD 22.  Different animal.