When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
So 2 days ago at start up I heard a pretty distinct thump sound which seemed to come from the front of the car.
checked under the hood and under the car in the garage and saw nothing so proceeded to drive normally.
when I arrived at my destination and parked still no visible issue. After an hour I came back to the car and there was a puddle of Pentosin under the front drivers side.
checked in the hood and the reservoir was soaked as well as the drivers side air intake and radiator hose.
I checked the reservoir levels (both ABC and PS) both were low. So I started the car with hood open to see if I noticed a leak…upon startup there was no visible leak. I then walked over to NAPA and got a couple quarts of Pentosin and put half a quart in through the ABC dip stick hole and less than a quarter cup in the PS reservoir.
Both levels read high on dip stick but I definitely loss a lot based on that puddle. After a couple minutes Pentosin started spewing from a tiny hole in the dipstick top. The spray pattern seemed to explain the fluid on the front engine bay.
after about 30 sec the spraying stopped so I turned the car off and another puddle began to accumulate under the front drivers side.
The vehicle ride level remained perfect so I started it up again and there was no more fluid spewing so I had the car towed to my Indy.
After the diagnostic, I was told the system showed no leaks and held pressure and they said the puddle under the car was due to having too much fluid.
???
I explained the loud thump I heard that morning and the fact that since doing a flush last June 2021 levels were perfect and there has been zero issues.
I explained further that I purchased 2 quarts of fluid as an emergency and used half before having it towed in which may account for fluids looking overfilled currently but doesn’t make sense when you consider fluids were perfect up to this morning.
My Indys response was to simply drive the car and if the leaking persists bring it back because based on visual inspection and the computer the system had no loss of pressure and no codes.
They also stated they did put more fluid in. I reluctantly drove the car home and it drove normal.
Yesterday I checked the fluid levels after the car sat overnight and the fluid was way above the full mark on both the ABC and PS dipsticks. I drove the car yesterday with no issues and when checking fluid with car running fluid levels were within the normal mark on the ABC dipstick and slightly above the high mark on the PS stick.
This morning upon start up I heard the thump I heard 2 days ago (didn’t hear yesterday upon startup).
I immediately checked under the hood and under the car and everything is bone dry. Ride level is unchanged and vehicle is driving normal.
So 2 days ago at start up I heard a pretty distinct thump sound which seemed to come from the front of the car.
checked under the hood and under the car in the garage and saw nothing so proceeded to drive normally.
when I arrived at my destination and parked still no visible issue. After an hour I came back to the car and there was a puddle of Pentosin under the front drivers side.
checked in the hood and the reservoir was soaked as well as the drivers side air intake and radiator hose.
I checked the reservoir levels (both ABC and PS) both were low. So I started the car with hood open to see if I noticed a leak…upon startup there was no visible leak. I then walked over to NAPA and got a couple quarts of Pentosin and put half a quart in through the ABC dip stick hole and less than a quarter cup in the PS reservoir.
Both levels read high on dip stick but I definitely loss a lot based on that puddle. After a couple minutes Pentosin started spewing from a tiny hole in the dipstick top. The spray pattern seemed to explain the fluid on the front engine bay.
after about 30 sec the spraying stopped so I turned the car off and another puddle began to accumulate under the front drivers side.
The vehicle ride level remained perfect so I started it up again and there was no more fluid spewing so I had the car towed to my Indy.
After the diagnostic, I was told the system showed no leaks and held pressure and they said the puddle under the car was due to having too much fluid.
???
I explained the loud thump I heard that morning and the fact that since doing a flush last June 2021 levels were perfect and there has been zero issues.
I explained further that I purchased 2 quarts of fluid as an emergency and used half before having it towed in which may account for fluids looking overfilled currently but doesn’t make sense when you consider fluids were perfect up to this morning.
My Indys response was to simply drive the car and if the leaking persists bring it back because based on visual inspection and the computer the system had no loss of pressure and no codes.
They also stated they did put more fluid in. I reluctantly drove the car home and it drove normal.
Yesterday I checked the fluid levels after the car sat overnight and the fluid was way above the full mark on both the ABC and PS dipsticks. I drove the car yesterday with no issues and when checking fluid with car running fluid levels were within the normal mark on the ABC dipstick and slightly above the high mark on the PS stick.
This morning upon start up I heard the thump I heard 2 days ago (didn’t hear yesterday upon startup).
I immediately checked under the hood and under the car and everything is bone dry. Ride level is unchanged and vehicle is driving normal.
Any insight would be greatly appreciated!
Puddle under drivers side Puddle after adding 1/2 quart pentosin Engine cover, air intake and front with pentosin over spray ABC dipstick slightly above full at normal operation temp and ride level ABC dipstick slightly below bottom level with car raised with button on dash
Lift the front left, pull the panels, and see what you find.
You can remove the line, take it to a hydraulic shop, and have them fix it for better and cheaper than replacing it. While you're in there, check for any other leaks. Don't run the car (obviously).
2007 S600, 2007 Chrysler 300 SRT8, 2000 C5 Corvette, and 2017 Mustang GT, and just got a 2023 300C
I had a similar loud bang only on start-up from the front left of the car. It was a bad accumulator. They are not expensive but it is a messy job and you have to pull the left side inner fender cover. I wouldn't wait. It has already signaled you it wants to be replaced. If you ignore it, you will find it puking green pentosin fluid all over your engine. While you are inside it, check all the hoses for wetness or leaks. And I change my ABC filter every 20-30K miles. When was yours last changed?
I had a similar loud bang only on start-up from the front left of the car. It was a bad accumulator. They are not expensive but it is a messy job and you have to pull the left side inner fender cover. I wouldn't wait. It has already signaled you it wants to be replaced. If you ignore it, you will find it puking green pentosin fluid all over your engine. While you are inside it, check all the hoses for wetness or leaks. And I change my ABC filter every 20-30K miles. When was yours last changed?
I last changed the filter to the newer 3 micron about a year ago (driven about 15K since) as well as new fluid.
All lines are bone dry.
Based on my preliminary research, the accumulator seems to be the culprit here, I agree.
There was a distinct humming between 50mph and 70mph that is now completely gone. The vehicle seems to be much quieter, is it possible the pulsation dampener also kicked the bucket?
I last changed the filter to the newer 3 micron about a year ago (driven about 15K since) as well as new fluid.
All lines are bone dry.
Based on my preliminary research, the accumulator seems to be the culprit here, I agree.
There was a distinct humming between 50mph and 70mph that is now completely gone. The vehicle seems to be much quieter, is it possible the pulsation dampener also kicked the bucket?
The pulsation damper is meant to stop the humming 🤷♂️
2007 S600, 2007 Chrysler 300 SRT8, 2000 C5 Corvette, and 2017 Mustang GT, and just got a 2023 300C
The pulsation dampener is a maintenance item. You have done a good job doing the ABC maintenance. How many miles on the car? And is that ABC pump also original? Just my 2 cents, but I would not wait on the accumulator and I would watch the ABC pump/pulsation dampener for more noise/vibration.
The first time I heard that loud bang, I needed to change my underware. I thought they were shooting at me.
The pulsation dampener is a maintenance item. You have done a good job doing the ABC maintenance. How many miles on the car? And is that ABC pump also original? Just my 2 cents, but I would not wait on the accumulator and I would watch the ABC pump/pulsation dampener for more noise/vibration.
The first time I heard that loud bang, I needed to change my underware. I thought they were shooting at me.
LMAO!!! Me too! I ducked when I heard the pop! I have 132K. Yes, the pump is the original. It was making noise (humming) and I was getting some steering wheel vibration/squealing before flushing with new Pentosin (ran 15quarts total) and changing the filter and everything has been virtually silent since (with exception to slight humming at 50-70mph which is now completely gone after this incident).
It’s interesting that my Indy didn’t even consider the accumulator. With no loss of pressure, no loss of ride height and no leaks but a significant loss of fluid… It just goes to show you not many techs have experiential knowledge of the V12s.
The diagnosis of “too much fluid” was completely nonsensical and evidence that they’ve never encountered this particular problem.
I had a similar loud bang only on start-up from the front left of the car. It was a bad accumulator. They are not expensive but it is a messy job and you have to pull the left side inner fender cover. I wouldn't wait. It has already signaled you it wants to be replaced. If you ignore it, you will find it puking green pentosin fluid all over your engine. While you are inside it, check all the hoses for wetness or leaks. And I change my ABC filter every 20-30K miles. When was yours last changed?
Do you have a resource for replacement of the accumulator? I found a video for the W220 that looks fairly straightforward but nothing on the 221 so far.
I’d imagine I’d need to have all 4 tires off the ground to relieve any pressure in the system to replace.
Here's my two cents. Somebody correct me if I'm wrong.
There are two marks on the ABC dipstick; the highest one is with engine off and the lowest is with the engine on. My German's not so good (this stick is written in German)... but the level drops with the engine running...
Anyway, I think there is a drop in fluid level (maybe a 1/2 liter), due to the compression of the "nitrogen bombs" (a reference to the way the bombs looked in Spy vs Spy in Mad Magazine, and something I picked up from the BMW crowd), aka accumulators, pulse dampeners....
I also think, one can conclude, if the ABC level drops on starting, your accumulators are okay. And, if not, the nitrogen/pentosin separator has burst on one or more of the bombs . And, it wouldn't be surprising if one bomb burst has a cascade effect because of the increased dampening load shared by the remaining nitrogen bombs.
Hope this helps. I haven't done mine on the S600, so can't add anything on bomb replacement. Others have posted about it. IIRC, getting a hold on the bomb is the challenge... some have a hex on the bottom and some don't...
Hey guys, SL550 owner here chiming in. Change that dampener ...mine wore out at 26k miles. I changed Pentosin and filter and the vibration continued until dampener was changed ..then vibration and noise left too. I only did this as a preventative maintenance measure no banging sounds or leaks and puddles. FYI there is ABC and ABC2 in the R230 series with version 2 fitted in 2007 which moved the dampener from driver wheel well to the topside of the pump and updates to the accumulators to prevent sags and leaks.
Suggest you peruse the R230 forums for the many knowledgeable posters who share valuable DIY solutions, notably “Rudely “ a moderator on another forum and regrettably a Former contributor here.
Not saying the 2 ABC systems these 2 different cars are the same they are not, but many of the design principles and problems created there in are same or similar.
LegitStreetCars went through hell with a CL65. He thinks the accumulator broke up internally and sent chunks of rubber through the system and caused him no end of aggravation.
LegitStreetCars went through hell with a CL65. He thinks the accumulator broke up internally and sent chunks of rubber through the system and caused him no end of aggravation.
I saw that never ending saga! No disrespect to LSC but he was doing some questionable stuff. At one point he went so far as to try to pressurize the Hydraulic system with shop air.
I’ve order the accumulators so hopefully I’ll get the replacement procedure soon.
I recently changed my radiator which on the M275 can be cumbersome. I watched a video where a guy pretty much took off the front of the car and the front subframe for the job… I only removed the hood latches and fan so these content creators are awesome but many of them are great Guinea pigs for “what NOT to do” in my experience.
Hey guys, SL550 owner here chiming in. Change that dampener ...mine wore out at 26k miles. I changed Pentosin and filter and the vibration continued until dampener was changed ..then vibration and noise left too. I only did this as a preventative maintenance measure no banging sounds or leaks and puddles. FYI there is ABC and ABC2 in the R230 series with version 2 fitted in 2007 which moved the dampener from driver wheel well to the topside of the pump and updates to the accumulators to prevent sags and leaks.
Suggest you peruse the R230 forums for the many knowledgeable posters who share valuable DIY solutions, notably “Rudely “ a moderator on another forum and regrettably a Former contributor here.
Not saying the 2 ABC systems these 2 different cars are the same they are not, but many of the design principles and problems created there in are same or similar.
Nice insight! I’ll check out the R230 forums and see what I find! Thanks so much
And Konigstiger, question: Are similar documents available for R230 beyond what was mentioned in a few of the W221 docs you posted.
Tip of the Sweaty Cap to you for doing this and all you do for this forum.
And Konigstiger, question: Are similar documents available for R230 beyond what was mentioned in a few of the W221 docs you posted.
Tip of the Sweaty Cap to you for doing this and all you do for this forum.
Interesting. So you just cranked off the accumulator with a chain filter filter wrench?!? The WIS instructions make this so much more complicated. You depressurized the system first?
06-18-2022, 07:09 AM
