khutchinson22

Walking out to my car tonight I noticed fluid on the ground from the front of the car. Put a little on the hand and what do you know, GREEN! My heart sank. Open the hood and there is fluid all over the ABC pump and in that general area. I turned the car on to see if I could pinpoint the leak under pressure and got the "ABC Drive Carefully" warning but couldn't see where the fluid was coming from. I am having the car towed home so I can tear it down.

My question is, what are the likely culprits? Pump was replaced at 54k and I have 112k on the car now. Otherwise I have no record of anything being done to the system.

Dr Matt

Probably the dead end hose. You will see it once you get under the car and remove the front underbelly plastic.

khutchinson22

Looking around under there and nothing is jumping out as an obvious issue.

khutchinson22

I did notice that there is oil all over the upper end and on the under side of the hood. Either the leak is coming from the resevoir or there is a lot of pressure coming from a leaking line down below.

Welwynnick

Obviously you really need to find the right source of the leak, and its not the easiest thing to do. You'll need to clean it all up and look closely.

If it really is coming from the reservoir, that's probably down to a failed accumulator. They go by different names, and have slightly different functions, but there's essentially four of them.

Its difficult to identify an individual failure with indirect trouble-shooting. You either need to remove or replace them one by one or all together. Not that difficult actually.

Did you notice any funny noises before it failed?

Nick

khutchinson22

I thought it was 2 accumulators and 1 pulsation dampener....

Is there any way to test this theory without replacing all those parts?

awiner

There are FOUR nitrogen spheres in the ABC system on a W215.

You can purchase the accumulators separately. Part for the front and rear accumulators (You need two) is: A220-327-01-15

Be advised there are two other nitrogen spheres in the system as well. One is mounted to the pressure relief valve (Part #A220-327-02-15) which is found in the front right side of the vehicle.

The other is a small nitrogen chamber (Called an Air Cell) that sits near the fuel pump in the driver side mid/center of the vehicle, (Part #A220-320-04-15).

You can take each one off, one by one and try to test for a punctured diaphragm, however at 100+k, the nitrogen starts to leak and reduce in pressure so it is a good idea to replace all of these units.

If one broke, another is not far behind.

khutchinson22

Thank you for all that!

I was planning to replace the accumulators/pulsation dampeners anyway but I want to make sure that doing so is also going to solve my current issue. Financially I can really only afford to repair what is actually broken now.

Would bad accumulators force fluid back up and out of the reservoir as described?

Welwynnick

Yup, that's the gist of it.

Just make sure that's where the oil is coming from.

Nick

khutchinson22

Is there any way to safely test this theory without destroying the pump?

Welwynnick

Has the ABC reservoir ever run dry?

As long as the pump is pumping (clean) oil, it's OK.

If the leak every gets so bad that the reservoir is empty, don't run the engine.

Simply filling an empty reservoir isn't enough, as the pump is NOT self-priming. You have push oil into the pump under a few PSI of pressure.

But if the reservoir was never empty, you're OK.

Nick

khutchinson22

The pump has never been empty. It's only slightly low now (maybe an inch below the proper level on the dip stick). Is the low oil level what set off the warning or what it triggered by system pressure?

khutchinson22

Is the one quoted here the pulsation dampener?


This is what came up on Amazon for the accumulator:





I can't find the Pulsation Dampener or the Air Cell on Amazon......

Welwynnick

That looks like an accumulator rather than the pulsation damper.

Descriptions on internet vendor sites aren't reliable, and there's no information there to even tie it to a manufacturer. You really need to search by part number.

Try parts.com or mbpartsworld.

Nick

khutchinson22

I ordered two from the Amazon link above as it said it was the Accumulator. I ordered the Air Cell and the Pulsation dampener from mbpartsworld.

khutchinson22

Installed all 4 units last night. Topped off the system. Added too much and it overflowed out of the dipstick vent. After losing about $25 worth of Pentosin I cleaned the mess and took her for a drive. All seems well. Let it sit overnight in the first position (one red light on switch) and, to my surprise, it was at exactly the same level this morning (the drivers side is typically lower after sitting for 6+ hours). No additional fluid had leaked out. Assuming I don't experience any issues over the next few days of driving then I will chalk this one up as a success! I have to admit, even though I am very skilled under the hood, I was a little nervous performing this repair after reading all the horror stories. In all honesty, it really wasn't that hard and if I had access to a lift it would have taken half the time.

Thanks for all the help, guys!

Welwynnick

Congratulations!

People are quick to post horror stories about ABC, or any high-tech engineering for that matter.

Its much better to fix ABC than replace it, isn't it?

Nick

tusabes

What was the cost for all four units and how many hours of labor did it take you ?

khutchinson22

Around $600 and about 3 hours. If id had a lift it could have been done in 2 hours.