ItsaHonda,

I too have this strange noise in my 1994 Accord EX Sedan. I have only used Mobil 1 5W30 since I bought the car back in July of 1994 new.

The knocking noise can be heard when I am in neutral or park around 2000 to 2500 rpms. If I goose the engine to this rpm you can really hear it. It sounds like a diesel engine. At faster rpms it goes away. I really don't notice it when I am driving, except when I listen carefully at a slow acceleration.

I first noticed it around 110,000 miles about a year ago. I now have 122,000 miles and the noise may be getting louder. I am now using Mobil 1 15W50 at the advice of the Service Manager of my local Honda Dealer. They can not tell me the exact cause of it without taking apart the engine! They checked a few common things that it could be and it wasn't. The car runs fine otherwise, doesn't burn any oil, and the exterior of the engine looks like it just came from the showroom.

The car has been to two dealerships for a diagnose. One said it was probably a misalignment of the balancer shaft belt. The other anything from a bad conrod bearing to a main engine bearing. Maybe when the car was assembled they picked parts with excessive tolerances???

I myself last year checked and cleaned the EGR Ports, and did a valve adjustment, expecting a miracle.

I wonder how many more people have this problem with this engine and just don't notice that it existS???

Michael