2001 silverado engine knock

[tahoe LT 99]

Every time I start my pickup after it's been sitting for awhile "cold start" I hear this knock that seems to last for about 5-10 seconds and the knock gets faster as I accelarate but it goes away after that 5-10 seconds. It never does it warm......it's been doing this for quite awhile. Any thoughts?

[tahoe LT 99]

OK I found this about my problem.......???


Engine Knock on Cold Start
1999-2002 Chevrolet and GMC C/K Pickup and Utility Models

2002 Cadillac Escalade (2WD)

with 4.8L, 5.3L or 6.0L Engine (VINs V, T, Z, U -- RPOs LR4, LM7, L59, LQ4)

This bulletin is being revised to add an additional engine to the models section. Please discard Corporate Bulletin Number 01-06-01-028 (Section 06-Engine).

Some of the above vehicles may exhibit an engine knock noise that begins in the first 19,000-24,000 km (12,000-15,000 mi) of use. The knock noise is most often noticed during initial start-up and typically disappears within the first 5-30 seconds (may last longer in extreme cold temperatures). The noise is usually more noticeable on the initial start-up when the temperature is below 10°C (50°F) and may be more pronounced on the first cold start following a long trip.

This noise may be caused by an interaction between carbon that has formed on the piston, the piston motion and the cylinder wall. GM Powertrain Engineering, and an analysis of engines with this condition, has confirmed that the noise is not detrimental to the performance, reliability or durability of the engine. THIS NOISE DOES NOT HAVE ANY EFFECT ON THE LONGEVITY OF ANY OF THE ENGINE COMPONENTS.



Important
At this time, attempts to repair this condition by replacing the engine assembly or pistons are not recommended.

[ukrkoz]

yeah, daahh
as usual, GM engineers and PR are quick to come up with another bs about "that's how it's supposed to be".

ok, you have pushrod engine or not? if yes, get used to that noise. it's typical for pushrod engines, as due to long pushrods, it takes time for hydraulic lifters to reach operating pressure and close gaps on rockers.

otherwise, if you are about 500 miles close to oil change, pour a can of Seafoam into cranckcase and drive on it. YES, I SAID drive on it, it's totally safe to do. it'll clean "carbon deposits" just fine.

they call it clunckerado for a reason. one thing i learned about this truck off MANY posts and my experiences. it's been designed by people that used to work for 19th century steam engine and carriages companies. everything got to be BIG and CONTINUOUSLY LUBRICATED. and clearencies are in tenths of inch, not of millimeter. BIG. and a lot of GM magic lube. A LOT.

[j cAT]

Originally Posted by tahoe LT 99

Every time I start my pickup after it's been sitting for awhile "cold start" I hear this knock that seems to last for about 5-10 seconds and the knock gets faster as I accelarate but it goes away after that 5-10 seconds. It never does it warm......it's been doing this for quite awhile. Any thoughts?

I had this problem...2000 5.3L sil... It is caused by using conventional oil , and oil that is not 5-30wt....the heavier the oil the worse it is...carbon in the combustion chamber does cause this noise to last longer than 5-30sec....more like 5 minutes...

when cold let engine warm up...2-3minutes before driving on it...

remember GM is off the hook after the warrantee ends that why they say no damage...that is b/s...


they screwed up on the tolerances so this has been an issue back when these vehicles first come out...so far I've eliminated this noise...