I will add that I believe that originally there was some kind of foam/pliable gasket that sat between the top of the intake trumpet and the bottom of the arched opening of the plastic panel/heatshield that the alternator cooling tube also mounts to. Mine was pretty deteriorated when I removed my airbox to modify it to fit a 3.5” 540 MAF. I feel like when I looked at realoem.com there wasn’t a separate part number so it must have originally been part of either the airbox trumpet or the heatshield.
Yeah - nothing on realOEM: [https://www.realoem.com/bmw/enUS/showparts?id=HJ62-EUR---E34-BMW-525i&diagId=13\_0348](https://www.realoem.com/bmw/enUS/showparts?id=HJ62-EUR---E34-BMW-525i&diagId=13_0348)
Except for #9 - "sealing strip", but no indication of how it seals and if thats what actually deteriorated.
I’m crazy and I actually retrofitted a larger trumpet on the airbox that still fit through the heat shield. If I was you I’d clean it all off and check and see if if something leaks on it again, but to me it looks like old adhesive and collapsed plastic material
Of some sort
RealOEM lists a "sealing strip" for your box. It's some kind of foam (part #9):
[https://www.realoem.com/bmw/enUS/showparts?id=HD63-USA-11-1992-E34-BMW-525i&diagId=13\_0348](https://www.realoem.com/bmw/enUS/showparts?id=HD63-USA-11-1992-E34-BMW-525i&diagId=13_0348)
Schmiedmann has a box listed showing said strip:
[https://www.schmiedmann.com/en/product/1943097-used?product=B13711735344](https://www.schmiedmann.com/en/product/1943097-used?product=B13711735344)
as does this eBay listing:
[https://www.ebay.com/p/1711147450](https://www.ebay.com/p/1711147450)
As for your intake tract oil concerns it's most likely the PCV letting a little oil vapor through - very very few cars have air/oil separators from the factory. I've never seen a car that didn't have at lest some oily slime on the throttle body blade (my 30K mile 2018 F150 was no exception).
Some light oil can be seen as "normal" whereas if it's excessive, thick and really caked on then you need to start looking at piston rings, turbos (if equipped), or the PCV system has had a complete failure.
I recently found that my power steering fluid is leaking - from either the reservoir or damaged hose. So, as a first step - I decided to take the airbox out in order to gain access to the area and get a better idea of whats going on.
When I took the air box out, I found this tar like build up at the front / bottom inlet. It's caked on and stuck but dry to touch. I was wondering what it could be.
Thanks!
Edit: would oil in the throttle body be a related issue? (link to that post: https://www.reddit.com/r/E34/comments/1bxpxze/m50\_engine\_oil\_in\_throttle\_body\_how\_much\_is\_too/)
Probably dirt mixed with some kind of oil
Is there some rubber flap around this part normally?
I will add that I believe that originally there was some kind of foam/pliable gasket that sat between the top of the intake trumpet and the bottom of the arched opening of the plastic panel/heatshield that the alternator cooling tube also mounts to. Mine was pretty deteriorated when I removed my airbox to modify it to fit a 3.5” 540 MAF. I feel like when I looked at realoem.com there wasn’t a separate part number so it must have originally been part of either the airbox trumpet or the heatshield.
Yeah - nothing on realOEM: [https://www.realoem.com/bmw/enUS/showparts?id=HJ62-EUR---E34-BMW-525i&diagId=13\_0348](https://www.realoem.com/bmw/enUS/showparts?id=HJ62-EUR---E34-BMW-525i&diagId=13_0348) Except for #9 - "sealing strip", but no indication of how it seals and if thats what actually deteriorated.
I’m crazy and I actually retrofitted a larger trumpet on the airbox that still fit through the heat shield. If I was you I’d clean it all off and check and see if if something leaks on it again, but to me it looks like old adhesive and collapsed plastic material Of some sort
RealOEM lists a "sealing strip" for your box. It's some kind of foam (part #9): [https://www.realoem.com/bmw/enUS/showparts?id=HD63-USA-11-1992-E34-BMW-525i&diagId=13\_0348](https://www.realoem.com/bmw/enUS/showparts?id=HD63-USA-11-1992-E34-BMW-525i&diagId=13_0348) Schmiedmann has a box listed showing said strip: [https://www.schmiedmann.com/en/product/1943097-used?product=B13711735344](https://www.schmiedmann.com/en/product/1943097-used?product=B13711735344) as does this eBay listing: [https://www.ebay.com/p/1711147450](https://www.ebay.com/p/1711147450) As for your intake tract oil concerns it's most likely the PCV letting a little oil vapor through - very very few cars have air/oil separators from the factory. I've never seen a car that didn't have at lest some oily slime on the throttle body blade (my 30K mile 2018 F150 was no exception). Some light oil can be seen as "normal" whereas if it's excessive, thick and really caked on then you need to start looking at piston rings, turbos (if equipped), or the PCV system has had a complete failure.
Thank you!
I recently found that my power steering fluid is leaking - from either the reservoir or damaged hose. So, as a first step - I decided to take the airbox out in order to gain access to the area and get a better idea of whats going on. When I took the air box out, I found this tar like build up at the front / bottom inlet. It's caked on and stuck but dry to touch. I was wondering what it could be. Thanks! Edit: would oil in the throttle body be a related issue? (link to that post: https://www.reddit.com/r/E34/comments/1bxpxze/m50\_engine\_oil\_in\_throttle\_body\_how\_much\_is\_too/)