Fuel Pump Issues

[khalida]

I have a c class 220 cdi which has just turned 3 years old so out of warranty. I had Mercedes have a look at the car before the warranty ran out.

The fuel pump is making a grinding, gratting noise especially at a cold start in the morning. The garage and Mercedes have said the pump is working so no repair or replaced it needed. My point to them was the pump is starting to fail while under warranty and will probably do so at some point. They have refused to do any repair but have said should this happen later then they will possibly consider helping with the cost at that point. I won't hold my breath in regards to that lol.
I feel they are abiding their time so that I will have to bear the full cost of the repair.
Has any other member had the same problem with fuel pumps and is there any advice you can give be regarding resolving this issue with Mercedes not carrying out any work under warranty.
Thanks

 

[mercedes13156]

Start your engine. Remove all dangling clothing, ties, jewelry, etc. You'll see why in a minute. Get a few socket extensions slotted together. About two feet long or more if you can. Put one end on your fuel pump under the round vacuum pump. This is the primary lift pump which pulls fuel in from the tank. Bend over and put the other end of the extensions on the bone just in front of your ear and behind the hinge on your jaw. (The little bendy bit) You'll be able to hear / feel very clearly what's going on inside the pump. It should "purr and whizz" quietly. If not, it's busted.

Put the extensions on the bigger triangular high pressure fuel pump and put the handle to your ear again. It should also "purr and whizz" quietly. Again, if not, it's busted.

Next try the waterpump, then the power steering pump, then the aircon pump, then the alternator. You should also touch it to the centre bolts on the idlers on the drive belt, NOT the revolving roller. I've had one with a worn bearing before and you'll hear very clearly what the bearings are doing.

This is a very cheap and effective way to find a noise in the engine bay. It is so good that you can even identify which of the tappets are correctly adjusted. That way you'll be able to point the mechanic to the noisy bit with absolute confidence.

Hope this helps!