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Matt
Matt, Mechanical Engineer
Category: Mercedes
Satisfied Customers: 22005
Experience:  BEng hons Mech engineering, in auto industry 22 years
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Have a SL500 R230 2003 model with 61K miles. After a 80

Customer Question

Hi
Have a SL500 R230 2003 model with 61K miles. After a 80 mile journey yesterday I noticed small leak of fluid in front of the front n/s wheel. It appears to be below the ABC compressor/tank???
No warning light indication showing. Have read horrendous stories regarding the ABC system - is it as I fear?
Grateful for advice.
Regards
Mike
Submitted: 2 years ago.
Category: Mercedes
Expert:  Matt replied 2 years ago.
Hello

can you tell me the composition of the fluid? is it oily? is it clear?
Customer: replied 2 years ago.

Hi Matt

This is a light oil type fluid - not clear. There are now two leak 200mm wide patches that have penetrated the concrete slabs of the drive. One patch is immediately in front of the front n/s wheel coming from the under tray (below the ABC pump?)and the other next to this in front of n/s wheel but just inside.

I haven't started or moved the car since I sent the first enquiry.

Mike

Expert:  Matt replied 2 years ago.
Hello Michael

1st thing to check is the level of oil / fluid in the ABC reservoir



this does unfortunatly sound like a leak from a strut or the pressure reservoir
Customer: replied 2 years ago.

Hi

The 'dipstick' in the larger front unit with ABC label shows fluid mid-way min - max. However there is a conical pot behind with a stubby dipstick which does not register although I can see some fluid in the pot.

regards

mike

Expert:  Matt replied 2 years ago.
Hello Mike

I'd say the next course of action is to remove the wheelarch liner to reveal the high pressure pump to see if you cna find the source of the leak

on no account drive the car with the main reservoir on low or empty as this will wreck the pump the fluid to top it up is Pentosin CHF 11S
Customer: replied 2 years ago.

Hi Matt

Is the main reservoir the conical pot with low fluid level or the ABC front unit which has a filler and dipstick? I will need to top up as I have made an appointment to get it looked at next week at a specialist and will need to drop the car off

I will look later at the hp pump behind the wheelarch liner - no doubt that is the culprit which I understand is costly to replace and cannot be repaired?

Mike

Expert:  Matt replied 2 years ago.
Hello Micheal

the main reservoir is the front unit with the dipstick ( see item 2 on the diagram I posted up)

it may not be the pump, as the high pressure reservoir and the actuators are also prone to leaks and they are a lot cheaper

but yes the pump cannot be repaired
Customer: replied 2 years ago.

Sorry Matt

Do I top up the larger main reservoir (front unit) labelled ABC with the small filler neck with dipstick which has still got fluid up to between min-max or do I top up the near empty conical pot sitting behind (is that a header tank?) as the diagram doesn't show both pots. I note that there are 2 pipes off this conical pot - a 30mm pipe heads to a nearby pump driven by the main pulley and the 2nd about 15mm pipe heads towards the front grille area?

Regards

Mike

Expert:  Matt replied 2 years ago.
Hello Mike

I think the conical pot is a damper volume
Also on the dipstick there are two sides, one for engine on (motor an) the other engine off (motor aus). The fluid should be within the indentation on the dipstick depending on the state of the engine, and not between the two indentations
Customer: replied 2 years ago.

Hi Matt

Sorry I'm still asking questions...

Im sure that the larger main reservoir is the front unit and marked A..B..C. It has the two sided dipstick but the fluid level is within the indentation i.e ok. So I cant top this up with Pentosin without overfilling??

However the conical pot behind which I think may be for the power steering is virtually empty and one of the outlet pipe heads towards the lower front wheel arch where I believe there may be a radiator? Can I use Pentosin for topping up that container to check loss?

Yes I need to remove the inner wheel arch liner to see the culprit of the leak.

Many thanks

Mike

Expert:  Matt replied 2 years ago.
Hello Michael

Ahh Ok

in that case yes by all means top it up but you need Dextron III ATF not the pentosin for the power steering

in this image the smaller vessel at the front is for power steering

Click image for larger version  Name:	PSReservoir.jpg Views:	279 Size:	87.2 KB ID:	267080
Customer: replied 2 years ago.

Hi Matt

The image shown is different from my SL500 engine bay. Mine does not have the smaller (PS) vessel in the front. Also the box shaped thing with the 4 bent metal pipes is on the offside wheel arch. The larger main unit (Oil Reservoir) marked A..B...C on the label and Hydraulic Fluid on the hose cap is the same as mine but I have a black conical pot, marked on both sides PA 66-GF, immediately behind which is virtually empty of fluid which I assumed is the power steering reservoir?

Can you see in my picture?

Regards

Mike

Sorry I should be adding Ratings

Expert:  Matt replied 2 years ago.

Hello

thats right the pot to the rear is for power steering fluid

however the Dextron is a dark red so don't think thats your fluid leak

but yes it sounds like it needs filling up

checking the level of this should be performed after a drive so as to warm the fluid as it expands a lot

so top it up to about halfway before driving then cehck again afterwards

and you can rate my answer at any time, our conversation will carry on for the allocated 7 days regardless ( if you need it to)

Matt and other Mercedes Specialists are ready to help you
Customer: replied 2 years ago.
Hi Matt
Took the inner wheel mudguard off today. Yes inside is the leaking valve unit it's covered in fluid so something has failed. What does puzzle me is the header tank still registers fliud between min and max?
I have to drive 3 miles to specialist mechanic on Tuesday so hope it does not discharge and empty the pump by then?
Thank for you help.
Now for the expensive bit!
Mike
Expert:  Matt replied 2 years ago.
Hello Michael

glad you've gotten to the bottom of it and 3 miles should be fine