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I've got a 10/99 build car. I don't think my oil compressor was changed out and nothing in my records say anything along the lines of oil compressor.

Why?
 

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Discussion Starter #3
Are you sure this part is equipped on your car? You couldnt replace it if it broke, can you confirm with pictures?
 

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I can't confirm with a picture. :( The car is tucked away under a car cover at this point.

Where is the part located though? It isn't in the oil pan, is it?
 

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Discussion Starter #5
I can't confirm with a picture. :( The car is tucked away under a car cover at this point.

Where is the part located though? It isn't in the oil pan, is it?
The diagram labels the oil sump line coming out right next to the oil level/temp sensor
&
Its external since it has banjo fittings, brackets and a vibration mount pictured
 

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I've always wondered what purpose the external compressor on some of the early MY E39 M5s served. My son has a 6/99 MY and no compressor.

--Peter
 

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Discussion Starter #7 (Edited)
I've always wondered what purpose the external compressor on some of the early MY E39 M5s served. My son has a 6/99 MY and no compressor.

--Peter
took a another look at the thread i found it in and nightkrawler looks to be right, it connects from the side of the oil pan to the vanos and it looks like it was a precursor to the pressure accumulator...

http://www.m5board.com/vbulletin/e39-m5-e52-z8-discussion/166210-has-anyone-ever-thought-about.html#post1932346



UP TO 12/2000
http://www.realoem.com/bmw/showparts.do?model=DE93&mospid=47592&btnr=11_2699&hg=11&fg=15


FROM 12/2000
http://www.realoem.com/bmw/showparts.do?model=DE93&mospid=47592&btnr=11_3200&hg=11&fg=15
 

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Now I know what you're talking about John. Even though mine is a 10/99 build, I have the setup in the second picture.
 

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You need to have 08/99 or earlier build to have that oil compressor. On a related note, since most cars' vanos accumulator has the electric shutoff valve, should we turning ignition to position 2 then hold for a few seconds so the accumulator can release the oil to prime the engine before firing it up, especially on cold days?
 

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Another theory (just what you needed) - that pump, which I don't believe ever got installed on the M5, connects to the distribution piece port where the cam-driven VANOS high pressure pumps tie in. Note the long banjo bolt (12) with two inlets, one for the cam-driven pumps, and one for this pump. (The accumulator ties in to the port on top.) And BMW designed it to run at lower rpm to keep the VANOS pressure at 100 bar (1500 psi) even at idle. I say that because I measured VANOS pressure at idle and it was only 700-800 psi. It didn't get to 1500 psi until rpm got up to ~2000 rpm. So that pump was to keep it at 1500 psi, even at idle. And then BMW figured, what the hell, nobody's gong to notice if VANOS is a bit sluggish at <2000 rpm, and dropped the whole idea.
 

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I have been looking for the right document but at this point I have so many M5 docs things are very hard to find. That pump was only installed on cars where the customer complained about start up noise. It was not for production and from my reading was never part of production. It was used only in the servicing of noisy cars.
 

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Google Translate does a horrible job but from that oddball high pressure line circled in red in the photo, and the posts, this guy had the mysterious compressor installed to fix his start-up rattle. Seems only early European cars got this fix before they came up with the much cheaper modified accumulator. I'll say one think for BMW - when they get it wrong, they pull out all the stops to fix it.

E39 M5 vanos kysymys (kuva) - BTCF Forum
 

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Just reviving this old thread and curious if anyone found confirmatory documents on this oil pump compressor. Mine is a 2001 US model and I wondered why the oil pan has an extra drain plug on the side. Turns out that it is for attaching the oil line to this electric compressor. Therefore if this compressor was discontinued, and not even available for US cars, why did they keep drilling and tapping a hole for attaching the hose on all oil pans?
 

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What Sailor said was correct.
“That pump was only installed on cars where the customer complained about start up noise. It was not for production and from my reading was never part of production. It was used only in the servicing of noisy cars.”
The reason the Service Bulletin is impossible to find is because it was superseded by the Accumulator with Shutoff Valve one and had the same number. It was also never released in the USA so you’ll now only find it on the mid 1999 TIS CD.
Here’s a photo of the pump that came off my 7/99 build:-

940428


There was also an even earlier Bulletin (I can’t remember if it was in TIS or was a HLI) where all 4 Vanos gears were replaced with 0.05mm oversize to reduce the tolerance’s and backlash in the helical gears.

940427


940429


940430


I’d suggest that the reason all the lower pans have the side blanking plug is because once production was changed to that of the modified part they weren’t going to produce 2 different parts for (in the scheme of things) a very small and bespoke production run engine.
 

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My beast is 12/98 build and it has that pump installed. I never checked it out but if they installed it to service early cars it either didn’t help or my oil compressor doesn’t work any longer....
 

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My beast is 12/98 build and it has that pump installed. I never checked it out but if they installed it to service early cars it either didn’t help or my oil compressor doesn’t work any longer....
They only work when unlocking the car and on crank to prime the Vanos system to stop Vanos rattle on start up.
They won’t stop the Vanos diesel noise at idle.
They’re pretty easy to test.
 
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