I changed the oil on my supercharger and despite taking precautions to not loose the oil drain/fill plug, I lost it never to be seen again. Does anyone know the size of that plug. I've scoured the web and cannot find a size. Its not M10 - 1.0. Too big. I just got a 1/8 NPT and that doesn't fit either. I got it to start but it got tight immediately so I stoped so as not to damage the SC threads. I'm close but no cigar at this point. I would assume that it is a metric plug as the head was 5mm Hex. Any help would be greatly appreciated. I'm at a loss right now.
MSG 55G
Super Member
close
Mar 29, 2025
- Join DateOct 2018
- LocationOC, CA
- Posts:699
-
iTrader Positive Feedback0
-
iTrader Feedback Score(0)
- Vehicle(s) I drive2006 E55
-
Likes:157
-
Liked:75 Times in 67 Posts
brads25 , 08-27-2011 07:54 AMFound It!
Air tools.. what a great investment, I used an Air Blower with extended pipe to get in there and literally blew it out!
Just in case you've done the same thing, (there's 2 of us already!) the plug is an 1/8" Taper Pressure plug and they're available on ebay.com and everywhere in the states. For some reason there aren't any in the UK.. how strange!
Quote:
brads25 , 08-27-2011 07:54 AM
Found It!
Air tools.. what a great investment, I used an Air Blower with extended pipe to get in there and literally blew it out!
Just in case you've done the same thing, (there's 2 of us already!) the plug is an 1/8" Taper Pressure plug and they're available on ebay.com and everywhere in the states. For some reason there aren't any in the UK.. how strange!
Thanks for looking. I hadn't found that thread, (excuse the pun). I have a 1/8" tapered pressure plug. I just tried it again in case I was cross threading, but I can get that barely seated. It looks square and it won't thread in any further. I put a little bit of force on it but stopped as it felt more than it needed plus with it being tapered, its only get wider from there down the thread.Originally Posted by MSG 55G
brads25 , 08-27-2011 07:54 AM
Found It!
Air tools.. what a great investment, I used an Air Blower with extended pipe to get in there and literally blew it out!
Just in case you've done the same thing, (there's 2 of us already!) the plug is an 1/8" Taper Pressure plug and they're available on ebay.com and everywhere in the states. For some reason there aren't any in the UK.. how strange!
To my mind it should be some sort of metric thread with it having the 5mm hex head and being a Euro car. I can't believe how much of a nightmare this is turning out to be.
There's a thread about this, or maybe it's in the s/c thread, but it turned out to be British pipe thread if I remember right.
Quote:
Thank you. I'll try and track one down. At some point I will run out of thread options and one will fit correctly. Once I get the correct one I'll post what worked. Wishing I had not done this "quick" maintenance job now. Originally Posted by StarvingArtist
There's a thread about this, or maybe it's in the s/c thread, but it turned out to be British pipe thread if I remember right.
bbirdwell
MBWorld Fanatic!
close
Today
- Join DateJan 2014
- LocationRepublic of Texas
- Posts:3,966
-
iTrader Positive Feedback0
-
iTrader Feedback Score(0)
- Vehicle(s) I drive'99 and '05 E55 AMG
-
Likes:370
-
Liked:1,315 Times in 1,019 Posts
Start with posts 4 and 6. #4 here:
https://mbworld.org/forums/w211-amg/...ml#post7550031
and #6 here:
https://mbworld.org/forums/w211-amg/...ml#post7550339
1/8" British Whitworth tapered pipe plug; British Standard Pipe thread uses the Whitworth standard. Not the most common thread available but you can get them via the internet.
FWIW, when I owned a Triumph 750 Trident with British Whitworth threads it was a PITA. If I lost a nut or bolt, I had to travel 90 miles to a Triumph dealership to get the hardware...
https://mbworld.org/forums/w211-amg/...ml#post7550031
and #6 here:
https://mbworld.org/forums/w211-amg/...ml#post7550339
1/8" British Whitworth tapered pipe plug; British Standard Pipe thread uses the Whitworth standard. Not the most common thread available but you can get them via the internet.
FWIW, when I owned a Triumph 750 Trident with British Whitworth threads it was a PITA. If I lost a nut or bolt, I had to travel 90 miles to a Triumph dealership to get the hardware...
Excellent info. I have a 1/8 BSP on order now in a 2 pack incase I screw up again. Very disappointed in myself over this.
I had reached out to the suppliers of the oil I purchased on eBay and they did not know. I'll update them if the BSP, sorry, WHEN the BSP fitting works.
Thanks for the input. I'll post what I find to work when I finally get it sorted.
I had reached out to the suppliers of the oil I purchased on eBay and they did not know. I'll update them if the BSP, sorry, WHEN the BSP fitting works.
Thanks for the input. I'll post what I find to work when I finally get it sorted.
For anyone else who manages to loose the grub screw plug while changing their Supercharger oil, I can confirm after over 2 weeks of not being able to drive the car that the correct plug is a 1/8" BSPT (British Standard Pipe Thread) Allen socket head plug.
I purchased a 2 pack from Amazon for under $10.00 delivered.
Thank you bbirdwell for pointing me in the right direction. Greatly appreciated.
I purchased a 2 pack from Amazon for under $10.00 delivered.
Thank you bbirdwell for pointing me in the right direction. Greatly appreciated.
MB World Stories
The Best of Mercedes & AMG
Explore
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
SilverE5588
Senior Member
close
May 10, 2026
- Join DateJan 2016
- Posts:337
-
iTrader Positive Feedback0
-
iTrader Feedback Score(0)
- Vehicle(s) I drive'15 E63S,'21 LCI M5
-
Likes:148
-
Liked:82 Times in 60 Posts
Quote:
I purchased a 2 pack from Amazon for under $10.00 delivered.
Thank you bbirdwell for pointing me in the right direction. Greatly appreciated.
Haha thanks for the heads up on the sizing ,may order preventatively - pre doing my fluid . Btw what s/c oil did you use ? Rule of thumb is to keep what comes out and refill it to the same spec ?Originally Posted by E55AZ
For anyone else who manages to loose the grub screw plug while changing their Supercharger oil, I can confirm after over 2 weeks of not being able to drive the car that the correct plug is a 1/8" BSPT (British Standard Pipe Thread) Allen socket head plug.I purchased a 2 pack from Amazon for under $10.00 delivered.
Thank you bbirdwell for pointing me in the right direction. Greatly appreciated.
I purchased a kit off of eBay. If you search E55amg supercharger oil refil kit it will show up. About $52 shipped. It comes with a syringe to extract the old oil and refil with the new. I had my car on a slope on my drive way to get the oil to flow to the front of the supercharger. To be honest I thought I should of got a lot more out that I did after spending a lot of time trying to angle the tube in different ways to extract as much fluid as possible. I then backed the car into the garage when it was level and added the new oil. Per the instruction with the kit you fill it up until it comes out of the refil hole. Mine took the entire 150ml bottle before it started to weep out. The old oil smells really but by the way. I looked on several forums and read a couple of guys arguing about how much should go back in. One saying the amount you take out and the other saying fill till it starts to weep out. 150ml is not a huge amount of oil so I’m comfortable with the option I chose especially as the instructions confirmed what I did. Then I lost my grub screw into the abyss. I called a few supercharger specialists and no one could tell me what the size was. I got in touch with the supplier of the oil and they didn’t know. I hope this thread helps future people taking on this task not have to go through my pain. The vehicle was stranded for over 2 weeks trying to track down the right one. There are a couple of videos on YouTube as well regarding this that you may want to watch
QUOTE=SilverE5588;7681188]Haha thanks for the heads up on the sizing ,may order preventatively - pre doing my fluid . Btw what s/c oil did you use ? Rule of thumb is to keep what comes out and refill it to the same spec ?[/QUOTE]
QUOTE=SilverE5588;7681188]Haha thanks for the heads up on the sizing ,may order preventatively - pre doing my fluid . Btw what s/c oil did you use ? Rule of thumb is to keep what comes out and refill it to the same spec ?[/QUOTE]
SilverE5588
Senior Member
close
May 10, 2026
- Join DateJan 2016
- Posts:337
-
iTrader Positive Feedback0
-
iTrader Feedback Score(0)
- Vehicle(s) I drive'15 E63S,'21 LCI M5
-
Likes:148
-
Liked:82 Times in 60 Posts
Thanks alot for the info. Yeah in a brief search prior asking here I got some contradicting opinions on the amount of oil . Mobil jet fuel II is the going stuff to run ?
Quote:
Yes. Thats what I used in mine. Ive put about 50 miles on it right now and all is well. Made sure the supercharger kicked in and it all sounds great and no leaks or concerns. MB says it's sealed for life. They do not define the length of time life is in their opinion. Good luck on the oil change. Getting that bolt back in is not the easiest job. The supercharger pulley is in the way. I ended up duct taping the plug to the end of a 1" long bolt to get the thread started square in the hole then put lock tight on the open threads and finished by locking it down snug with a hex / Allen wrench.Originally Posted by SilverE5588
Thanks alot for the info. Yeah in a brief search prior asking here I got some contradicting opinions on the amount of oil . Mobil jet fuel II is the going stuff to run ?
Most people recommend Mobil Jet Oil II, but there are alternatives such as AC Delco Supercharger Oil and isn't as expensive as the Mobil Jet Oil.
Newbie
Quote:
I purchased a 2 pack from Amazon for under $10.00 delivered.
Thank you bbirdwell for pointing me in the right direction. Greatly appreciated.
Originally Posted by E55AZ
For anyone else who manages to loose the grub screw plug while changing their Supercharger oil, I can confirm after over 2 weeks of not being able to drive the car that the correct plug is a 1/8" BSPT (British Standard Pipe Thread) Allen socket head plug.I purchased a 2 pack from Amazon for under $10.00 delivered.
Thank you bbirdwell for pointing me in the right direction. Greatly appreciated.
thanks for the info. Changed my oil today, had a towel to catch the plug but it still vanished when I went to put it back in. Could you please post the link of which plug you purchased? I’m searching for the BPST but there’s a lot of different ones. Pls help! Lol thank you!
Just pull the supercharger and find the plug. Easy work. Then you can tip the supercharger up on end and get all that uber stank oil out of it.
Newbie
Quote:
Originally Posted by JohnLane
Just pull the supercharger and find the plug. Easy work. Then you can tip the supercharger up on end and get all that uber stank oil out of it.
honestly don’t wanna do all of that if I don’t have to. Seems like a little too much work for just a stupid plug. If there’s other options out there such as ordering a new plug, I’d rather exhaust that option first lol. Worst case, I’ll take it off and dig for it. I suspect it fell somewhere behind the oil filter housing. I’ll try to blow air in there and see if I can locate it that way and extract it with a magnet tool. Fingers crossed 🤞🏽
Newbie
Quote:
Originally Posted by mohsin52
honestly don’t wanna do all of that if I don’t have to. Seems like a little too much work for just a stupid plug. If there’s other options out there such as ordering a new plug, I’d rather exhaust that option first lol. Worst case, I’ll take it off and dig for it. I suspect it fell somewhere behind the oil filter housing. I’ll try to blow air in there and see if I can locate it that way and extract it with a magnet tool. Fingers crossed 🤞🏽
UPDATE:
found the screw after searching for 35 mins!!!! It was behind the tensioner pulley just sitting there hiding on the block. Got it put back in, went in tough because of the thread tape but it worked!
nd-photo.nl
MBWorld Fanatic!
close
Dec 14, 2025
- Join DateMay 2022
- LocationThe Netherlands
- Posts:1,917
-
iTrader Positive Feedback0
-
iTrader Feedback Score(0)
- Vehicle(s) I drive2005 CLS55 AMG W219 C219
-
Likes:534
-
Liked:499 Times in 429 Posts
Happy days 
Currently Active Users (1)
