Background: After lifting the car and probing a bit, my 2005 SLK55 RPM-dependent and annoying growl is definitely coming from the oil pan/sump area of the engine and not the 722.9 transmission. Good news...I believe.
Apparently, I have a classic M113-stuffed in-a-SLK55 oil pump growl (aka: https://www.slkworld.com/threads/slk55-m113-oil-pump-whine.615243/?post_id=5075457#post-5075457), or...do I have something more serious? According to this thread (https://www.slkworld.com/threads/th...threads/the-m113-whine-oil-dependent.581893/page-2?post_id=4926078#post-4926078) my very recent move from 'the oil in the engine when I bought it' (Shell? MB?) to Liqui Moly likely caused in increase in the noise, and my next move should be to Castrol Edge [Euro 0W-40] in the hope the noise 'generally' disappears. But, before I do that: the collective of AIs I've conversed with suggest to attach an oil pressure gauge to the engine port and confirm the oil pressure is solid and the pickup tube gasket has not failed/ruptured, which would (in theory) cause cavitation in the oil pickup tube and add to the M113 'growl'. Bottom Line: Is measuring the oil pressure warranted, or should I just skip to swapping in Castrol Edge? Or am I on the wrong track entirely about tempering the growl in my M113? Note:engine has ≈8.0 liters of oil in it, and all digital measurements check out 'good/as-expected'.
Apparently, I have a classic M113-stuffed in-a-SLK55 oil pump growl (aka: https://www.slkworld.com/threads/slk55-m113-oil-pump-whine.615243/?post_id=5075457#post-5075457), or...do I have something more serious? According to this thread (https://www.slkworld.com/threads/th...threads/the-m113-whine-oil-dependent.581893/page-2?post_id=4926078#post-4926078) my very recent move from 'the oil in the engine when I bought it' (Shell? MB?) to Liqui Moly likely caused in increase in the noise, and my next move should be to Castrol Edge [Euro 0W-40] in the hope the noise 'generally' disappears. But, before I do that: the collective of AIs I've conversed with suggest to attach an oil pressure gauge to the engine port and confirm the oil pressure is solid and the pickup tube gasket has not failed/ruptured, which would (in theory) cause cavitation in the oil pickup tube and add to the M113 'growl'. Bottom Line: Is measuring the oil pressure warranted, or should I just skip to swapping in Castrol Edge? Or am I on the wrong track entirely about tempering the growl in my M113? Note:engine has ≈8.0 liters of oil in it, and all digital measurements check out 'good/as-expected'.
