What is that ticking noise Im hearing when the engine is idling and Im near the front wheelwell?
This “ticking” noise has a lot of people baffled, including GM. The noise is most prevalent on engines with a few thousand miles or less, and soon after changing the oil on some engines with higher mileage (10,000+). Here is what we think: The 2001-2004 LB7 Duramax 6600 operates with a high oil pressure, running somewhere in the 60 psi range when hot. This high oil pressure produces more oil flow that is used to cool the pistons and better lubricate other parts of the engine, which adds durability. Experts has suggested that this high volume and pressure can cause an occasional air bubble to pass through the crankshaft oil galleries, which then “pops” under compression loads in the rod and main bearings. We’re told this condition has no short-term or longterm effect on engine durability. GM reduced the oil pressure on later LLY & LBZ engines. We suspect they did this to reduce the ticking noice.
