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Discussion Starter #1
I've only put around 400 hundred on this engine, it's was a 02/2002 build car and has 131,000 miles. I changed the rod bearing and replaced the timing chain guides. I thought I had it full of oil and only after around 340 miles it was at the add mark. $12 to $14 of oil every 400 miles is not real good, there isn't any leaks and not a wisp of smoke from the exhaust. Since then I've learned it must be checked while hot, it was indeed at the add mark. Now while hot it is at the full mark but when the engine is cold it's well above the full mark. Is this right?
If it is drinking that much oil why is there no smoke? I haven't even noticed any residue on the back of the car.
And the third oddity is a hum, sort of hear it at idle and is louder with rpm. I have run the engine without the drive belts so it's not a pump or idler bearing. I cleaned ( or at least tried to) the oil separators, they are the original ones. I will be replacing them and the hoses soon. Could these be causing the hum? On m62s a hum can be caused by the ccv on the back of the manifold, but the S doesn't have one.
 

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Trevor7008,

Doesn't sound right to me. Oil should read higher on the dipstick when at operating temp, lower when cold. It is a liquid and will expand when heated.

Something else is missing here, perhaps engine was not at full operating temp when measured, you did not wait long enough for some of the oil to drain back into the pan before measuring hot temp or maybe you measured it in two different spots where the floor might be uneven and giving a false reading on the dipstick? Just some thoughts.

Read that link, the oil has to be going somewhere, it can't just disappear.
 

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Since then I've learned it must be checked while hot, it was indeed at the add mark.
asking the obvious but are you checking it per the specific instructions in the manual? Start car and run for 15 seconds then turn off. Check oil level one minute after you shut off. Are you doing that?
 

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It is going somewhere. It's draining from the filter housing to the sump, raising the oil level in the sump.
I agree but shouldn't the oil drain back whether it is hot or cold? Are you thinking the hot oil takes longer than say a couple of minutes to drain back? Just wondering...
 

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Discussion Starter #7
And the hum could be the oil filter housing touching the inner fender. Sounds strange but it's a well known problem. I had to put a dent in the inner fender to give enough clearance even after replacing the two rubber housing mounts, which are prone to failing.
Since the engine is in a E38 some things are non-standard. I am using 740 oil lines and the filter is hanging on a 750 bracket. When I was mocking things up I knew I needed a buffer between the housing and fender, but then on final assembly I forgot. Stuck a piece of rubber between the two before I left work and BOOM noise is gone:)

I checked the oil cold, well above the full, got home oil temp about 210F. idled for a few seconds, then checked after a few minutes, right at the full mark. Right now I would say it's correct. I'll know what its oil consumption really is this weekend to and from Bimmerfest.
 
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