1999 E300D 210 Fuel Leak

[Bruce Bonds]

My brother and I are trying to locate a fuel leak in his '99 E300D. The car was parked overnight on an incline with the nose downhill, and a spot of fuel about 18 in. diameter formed under the engine. Fuel had evidently accumulated and spilled from the protective plate because of the incline. It is very difficult to see where the leak originates and he is going to remove the washer reservoir for a better look.

It looks as if the leak is in the area of the clear fuel lines above the IP. My questions are:

Is this a common place for leaks?

Do these lines get brittle and crack?

One thread said that the O-rings where these lines attach are a common problem. How difficult is it to replace the O-rings without removing the aluminum manifold?

Is there another place around the IP that is prone to leak?

Thanks,