86 560SEL Noisy Fuel Pump at Startup - PeachParts Mercedes-Benz Forum

GradyService · #1 02-05-2008, 11:29 AM

When you crank up the 560, it sounds fine. However, when you place it in reverse or drive, for about 30-45 seconds, you hear this groaning noise. If you keep going, it quits. I had my mechanic look at the rear end, cv shaft, rear brakes, etc, and he could not find anything wrong. I also had him drive it, and he couldn't find the problem. However, he said that "the fuel pump is a little noisy". As I understand it, there are 2 fuel pumps on this car, one inline, and one intank. Is the inline pump being noisy at startup a sign of an impending failure?

Dave

GradyService · #2 02-06-2008, 06:30 PM

It is now noisy all of the time. From my search, it seems that this is either a clogged filter making the pump work too hard, or the pump/pumps are on their way out.

Dave

pmckechnie · #3 02-06-2008, 08:02 PM

The 86 560 has 2 pumps but both are mounted at the same place, just behind the rear axle toward the right side of the car. I believe I would replace the filter mounted at the same location as the pumps. If the noise continues unplug the pumps one at a time to see which is making the noise. The reason for replacing the filter first is because it may be the problem and probably needs it anyway.

GradyService · #4 02-06-2008, 09:36 PM

The fuel lines/fittings around the pumps are all very rusty/corroded. Should I shoot them with penetrating oil (WD40/PB Blaster), in hopes that they won't fall apart when I go into it, or should I start pricing fuel lines/fittings?

Thanks, Dave.

pawoSD · #5 02-06-2008, 10:59 PM

You'll need new parts, I'd have them on hand. Lines that are rusty/corroded rarely come apart nicely.

GradyService · #6 02-07-2008, 12:38 PM

Are the lines only available from a MB Dealer, or are they an aftermarket item?

Dave

GradyService · #7 02-07-2008, 03:35 PM

Called the MB Dealership in Fayetteville. The section of line from the pumps to the filter is 43.00, and the line from the filter to the rubber hose is 37.00. They said it was unlikely that any aftermarket supplier would have them.

Dave

E150GT · #8 02-07-2008, 03:57 PM

Yes the lines will need to be replaced ,as mine sprung a leak when I changed the fuel filter. DO NOT replace them on a sunday afternoon as I did without replacement parts!!! You will also need a few new crush washers available from the dealer also or the lines will not seal up. I know this. You can get these hoses from here at Fastlane ,but I doubt any place like Autozone will have them in stock.