1994 Merc 5.7. There is a clacking noise that comes from the front of the engine at high rpms. Mainly when you gun it out of the hole and if you're running above 3800 rpm. Cruising at 3200 or so there is no noise. Seems to not happen as much after you've run for awhile. This is not constant. Sometimes at higher rpm it doesn't do it at all. Clacking is not rythmic, totally random. It sounds like it's coming from the very front of the engine, bit I can't isolate exactly where. Water pump, timing chain, I can't tell. There is never any loss of power and will run all day. Never overheats. Runs perfect. And like I said, sometimes it never makes the noise. Just wanting to maybe get an idea or maybe someone else has dealt with this. Thanks in advance.
