SL55/63/65/R230 AMG: ABC Under Bonnet Oil Leak ?
Thread Starter
Junior Member
Joined: May 2006
Posts: 17
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From: Essex, UK.
ABC Under Bonnet Oil Leak ?
Hi everyone,
I've read a lot about our ABC system and knew when I bought my 2002 SL55 that this might be an issue and sure enough, 6 months in a new rear shock had to be fitted!
Yesterday the wife brought it home with the RED ABC dash warning on and I spent most of last night and this morning reading up on peoples advice - I think once I have fixed it a flush through with new fluid and a magnetic filter seems to be the general feeling from the group but, before I get to that...
The oil level is low and there has been nothing on the floor recently but a look under the bonnet shows clearly some oil has been spraying from somewhere but anyone any idea where this might have been from as it's all over the place but no obvious split pipe etc ?
Ideas where to start ?
Thanks - Justin
I've read a lot about our ABC system and knew when I bought my 2002 SL55 that this might be an issue and sure enough, 6 months in a new rear shock had to be fitted!
Yesterday the wife brought it home with the RED ABC dash warning on and I spent most of last night and this morning reading up on peoples advice - I think once I have fixed it a flush through with new fluid and a magnetic filter seems to be the general feeling from the group but, before I get to that...
The oil level is low and there has been nothing on the floor recently but a look under the bonnet shows clearly some oil has been spraying from somewhere but anyone any idea where this might have been from as it's all over the place but no obvious split pipe etc ?
Ideas where to start ?
Thanks - Justin
Thread Starter
Junior Member
Joined: May 2006
Posts: 17
Likes: 0
From: Essex, UK.
fxrs1955 - I had noticed the car was low on the rear right hand side most days but it soon pumped up, do you think this is related then? - I have whipped the bottom plastic undertray in the left hand front corner and there was quite a lot of oil on it.
Senior Member
Joined: Aug 2013
Posts: 273
Likes: 2
From: Dallas, Texas
2014 SL550
What happens is the bladder in the accumulator goes bad and it takes on oil. The accumulators are shock absorbers for the ABC system. When they go bad and you hit a bump the shock is transfered to the rest of the system and in my case the reservoir would in effect burp fluid. You might try the bounce test and see what kind of rebound you get. They're not that difficult to replace and there's a video or a how to in these forums. If you're burping fluid that could account for the oil you're seeing.
Thread Starter
Junior Member
Joined: May 2006
Posts: 17
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From: Essex, UK.
A very graphic image I have now 
- thanks
Well I bought some oil and a filter from the local dealer (who was really helpful actually) and have topped up the fluid pot and I can now get the ABC to work and have cycled it up and down about 10 times and there is no leak I can see so your idea might be right - interestingly the engine sounds quieter but that might just be my imagination.
I was reading about the corroded washer issue and wondered if it might be that but as I say, nothing dripping that I can see.
I think I need to wash all the old oil off and take it for a drive and look again for the source.
Oil was part number A001 989 24 03 10 which was £20 per litre and the filter A003 184 61 01 at £25 so not bad prices to be honest.
I shall now have a search about for a good thread on the accumulator replacement in case I have to do that.
- thanksWell I bought some oil and a filter from the local dealer (who was really helpful actually) and have topped up the fluid pot and I can now get the ABC to work and have cycled it up and down about 10 times and there is no leak I can see so your idea might be right - interestingly the engine sounds quieter but that might just be my imagination.
I was reading about the corroded washer issue and wondered if it might be that but as I say, nothing dripping that I can see.
I think I need to wash all the old oil off and take it for a drive and look again for the source.
Oil was part number A001 989 24 03 10 which was £20 per litre and the filter A003 184 61 01 at £25 so not bad prices to be honest.
I shall now have a search about for a good thread on the accumulator replacement in case I have to do that.
Thread Starter
Junior Member
Joined: May 2006
Posts: 17
Likes: 0
From: Essex, UK.
Well, I jacked up the front end and removed the underbody protective trays (which were full of oil) but I didn't have to take it for a drive, in fact I just reversed in and out of the garage and the nice clean oil I had just added was all over the floor. 
Putting it back in the air shows it coming from the ABC pump, maybe from behind the pulley so there's my (expensive) answer. The dealer actually has no time in the system for this job but he checked some previous invoices and it's normally between 4 and 6 hours work and in the worst case 8 hours - It looks too complicated for me to attempt myself.
Interestingly there is nothing in their instructions to flush the system but he agreed that it was a sensible thing to do give the metal fragments that could be floating around in the system ready to destroy the new pump.
Putting it back in the air shows it coming from the ABC pump, maybe from behind the pulley so there's my (expensive) answer. The dealer actually has no time in the system for this job but he checked some previous invoices and it's normally between 4 and 6 hours work and in the worst case 8 hours - It looks too complicated for me to attempt myself.
Interestingly there is nothing in their instructions to flush the system but he agreed that it was a sensible thing to do give the metal fragments that could be floating around in the system ready to destroy the new pump.
Senior Member
Joined: Aug 2013
Posts: 273
Likes: 2
From: Dallas, Texas
2014 SL550
Find an indy to do the work. Mercedes doesn't recommend ever flushing the system but it's a good idea to flush and change the filter when you buy a used SL, and certainly when you replace a pump.
