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What is this engine part? (Getting to know my M54 engine bay)

219K views 144 replies 35 participants last post by  Dynamic Entry 
#1 ·
Over time, I've come to know (by necessity) almost every large item in the M54 engine bay ... but some items still are unknown to me ...

What is this engine part?

 

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#37 ·
I was trying to keep mostly to pictures, especially in situ pictures, but this cutaway diagram of the BMW M54 engine is too revealing to pass up:

 

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#44 ·

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#45 · (Edited)
Here is a clean shot of my M54 engine Bosch 120 OEM alternator, with the airbox removed so it can more easily be seen:
- AAA is towing my car in 30 minutes (total electrical failure)


And, here, circled, is another view of my VANOS solonoid adjusting unit:
- AAA is towing my car in 30 minutes (total electrical failure)


Yet another VANOS solenoid adjusting unit on my M54 engine, this one (gunked up) under the apparently leaking valve cover gasket:
- AAA is towing my car in 30 minutes (total electrical failure)
 

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#46 ·

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#47 ·

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#48 · (Edited)
Here, from underneath, are the tensioners and pulleys for my M54 belt-drive system:
- AAA is towing my car in 30 minutes (total electrical failure)



And, here is the diagram from the Bentleys of the M54 belt-drive system:
- AAA is towing my car in 30 minutes (total electrical failure)


Starting from the crankshaft inner pulley, the larger belt goes counterclockwise to the upper mechanical tensioner, then to the water pump, upside down to the idler roller, and then right-side up to the alternator pulley, and down to the power steering pump pulley at bottom right, and then back to the inner crankshaft pulley at bottom center.

The outer belt goes from the outer crankshaft pulley at bottom center counterclockwise upside down to the lower mechanical tensioner rightside up to the air conditioning compressor and then back to the outer crankshaft pulley.
 
#49 · (Edited)
#50 ·
My M54 passenger side vanos solenoid (covered in valve cover gasket leak grime):


My M54 fan clutch & waterpump connection:


My M54 upper radiator nipple connection to the expansion tank:


My M54 expansion tank cap and bleeder screw geometry:
 

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#55 ·
all the wires going to it are brown. Brown = chassis ground.
Thanks Mark.

You've helped a lot on this thread; and I appreciate your efforts!

that looks like a starter solenoid with the larger round case below the actual starter motor.[/quote]

Ah, I see what you mean. Thanks for the update. The hope is that we can identify ALL the 'objects' in the E39 M54 engine bay.

This is not only for me; but also for anyone asking where a certain part is. The hope is that this one thread contains pointers to everything visible, so that we can just point 'em to this thread to learn about their engines.
 
#56 · (Edited)
that looks like a starter solenoid with the larger round case below the actual starter motor.
Ah, I see what you mean. Thanks for the update. The hope is that we can identify ALL the 'objects' in the E39 M54 engine bay.

This is not only for me; but also for anyone asking where a certain part is. The hope is that this one thread contains pointers to everything visible, so that we can just point 'em to this thread to learn about their engines.

 
#57 ·
Today, I ran into this picture from 16valex of an E39 engine part from this thread:
- E39 (1997 - 2003) > 2001 525i, pcv location-replacement

What it is, though, I'm not sure.

16Valex was responding to this post:
It's located behind the reservoir for the power steering and under the intake manifold--one hose coming in and one going out--there will also be an electrical hook up on it--when I had this code come up I cleared it by tightening the gas cap on the car and that worked for awhile--then I removed the rubber 0 ring on the gas cap and on the 0 ring there on the outer edge of it I filled that area with black Permatex gasket maker and let it sit up overnight. By doing this -it made a tighter seal around the cap.. Year later my purge valve did fail and need replacing at that time though.
Hope that helps
So, I 'assume' this is the 'purge valve' from the prior discussion; and, it may be worth noting the picture itself was saved as 'breather valve'.

 

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#61 · (Edited)

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#63 ·
i always wash it while the engine is running....first have a spray nozzle attached to the water hose water the engine while its running then use an engine cleaner spray can leave it for about 2 minutes and keep the engine running the spray it back with water the heat of the engine and the spray cleaner will clean it like its a new engine....after you spray the engine with water get an air hose and dry your engine with an air nozzle and you will see the big difference..
 
#64 · (Edited)
Based on this thread today:
- What is the purpose of these funny-looking wires in the battery box next to the fuses

This picture below is of a ...


Don't have them in that location in my car.
They look like the "ground shoes" that are bolted to the body just below my RR tail light in my car.
It's a splice point to connect many wires together.
If all the wires in them are brown it's a ground connection.


x2 JimLev is correct, they are splice strips often used from the factory instead of butt splices where wires may need to be added/removed. you can absolutely test from them, assuming you know what your doing.
Likewise, this picture below is a comb-type ground connection.




 

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#66 ·
Regarding spraying down the engine bay: I do not know enough about it to give an opinion myself. But I used to work at a BMW dealership for 5 years, and we used to spray the engines (with a high pressure spray gun) for every car that came through for service, as well as any cars getting detailed. Many people at the dealership would bring up issue with this practice from time to time, and the mechanics reassured us that there was no damage we could do unless we held the nozzle within inches of a radiator hose or something. In fact, we even used to spray degreaser all over the engine before giving it a blast with the high pressure hose. All I can say is that after seeing literally thousands of cars get their engines blasted with the high pressure hose, there was never a problem; at least that we ever heard about.
 
#70 · (Edited)
Here are my fuses numbered 1 to 45 in my 2002 525i glovebox:
- Need help with location of the fuse boxs and overview of fuse positions for 528i?


And, here are my fuses F46 to F66 in my battery trunk compartment:


Fuses 75 & 76 are BEHIND the glovebox:
- Auxiliary Fan write up
Quote:
*******> ********>
Originally Posted by SleekBMW
This is a pic of fuse 75 and 76 lookin lying down above into your glove compartment from the passenger side foot well. That panel needs to be pulled BACK towards the passenger side seat with SLIGHT pressure to the floor and should come out. THE AREA THAT 75 and 76 are in is circled. you will reach in there, and grab the fuse and push UP towards the sky and it will come out.
*******> ********>


I'm not sure the numbers, but there are some fuses in the passenger side cabin air filter ebox:
- Request clarification of what is inside the ebox under the passenger cabin air filter


And, here is the high-amperage fusebox for fuses #F100 to F106 in the battery trunk compartment:


From JimLev, here's what's under that white F100 to F106 fusebox cover (looks like 8 fusible links?):


And, fuses 107 to 114 are under the passenger seat carpet (this picture from cn90's Bimmer):
- DIY: Troubleshooting S.A.S. and How to Replace the Famous Fuse # 107!



Note: Newer E39s have three relays above these fuses; older E39s have four relays instead of three:

  • Rear window defogger relay
  • Central locking relay
  • Unloader relay (arrow below is pointing to it)
  • Fuel pump relay <== only in older E39



And, here's the BMW battery with the two decals pulled up ...


EDIT: Bentley, Volume Two, pages 610-29 to 610-37 shows the 88 fuse spots (F1-F5, F1-F114 inclusive) in the 6 fuse locations listed below (spots F67 to F74 & F77 to F99 don't exist):
  • Fuse panel 1: F1 to F45 <= in the glove compartment top panel (45 fuse spots)
  • Fuse panel 2: F46 to F66 <= directly above the battery (21 fuse spots)
  • Fuse panel 3: F1 to F5 <= at the back of the ebox under the passenger side cabin air filter housing (5 fuse spots)
  • Fuse panel 4: F107 to F114 <= under passenger side front seat carpet (8 fuse spots)
  • Fuse panel 5: F100 to F106 <= above the battery positive terminal (7 fuse spots)
  • Fuse panel 6: F75 to F76 <= behind the glove compartment (2 fuse spots)
 

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#71 ·

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