jpeter6981

Hello all.

I have been asking around on the "other" MB site, but no luck thus far, so thought I may check here as well.

2004 E320 Wagon, 157,000 miles.
Has new (all OE parts):

Water pump
Belt Tensioner
Idler pulley
Thermostat
AC Compressor Pulley
Power Steering Pump
Valve Cover Gaskets
Rebuilt injectors
All new vacuum/rubber engine pieces
ALL fluids (and MB filters)
Complete front end rebuild
Many other new parts

Car runs great, gets excellent mileage (28/26) and the engine is very quite at idle.

I am having a strange noise issue. Ever since I have owned this, the engine has made a low "clicking" sound when the engine is cold, while accelerating. It also sounds kind of like the purge valve, but I unplugged and no change. Once warmed up, the noise goes away. No check engine or other codes.

a. Noise is not noticeable at idle (even when revving engine)
b. Seems to only be noticeable when accelerating, not coasting and increases in speed with engine speed.
c. Goes away completely with warm engine. / few mile drive
d. Air conditioning / fan on or off no difference.
e. Transmission in S/E no difference.

So, the question is, what is engaging under all of those circumstances? The only other thing I could think was perhaps a small exhaust header leak. It really sounds like the purge valve, but it's not. And I believe if it was lifters, would it not be noticeable at idle?

I appreciate any and all thoughts and ideas. I have had a number of M112/M113 vehicles and do not remember this with any others.

Thanks.. Jeff

Overheated

As it takes awhile for oil to circulate to the top of the engine when cold, if the noise is top end and only when cold, I'd offer it's a valve or valve guide.

jpeter6981

Thanks. But the oil is definitely well circulated I believe. The noise is not noticeable while idling, just on acceleration.