silverado

heres a dum question how come when i first start my truck thers a little nock for like 2,3 seconds then it stops. thanks :screwy:

I would think its just the oil getting circulated??

What brand oil filter is on it. Cheaper filters such as Fram have no or poor anti drain back valves and on the 4x4 with the filter sideways the oil drains out until you start it again. I personally use A/C, Napa gold or Wix filters.

thanks guys, i use ac delco for my parts,you guys think adding (lucas oil addetive) is a good idea..........

thanks for any info :icon16:

No lie, Lucas is some good stuff, but if your not having any smoking, or heavy, steady knocking, I'd leave it out...thats just my personal opinion though. I've run it in a F-150 before and it helped..it also had close to 200K very hard miles on it..

Hey, PULL, I'm not sure if I would use Lucas additive. That stuff is thick as thick as RTV when it comes out of the tube. I know that the oil will dilute it when you get it into your motor. But exactly how many miles do you have on your motor to warrant this thick of an engine treatment? Your motor was built with pretty tight tolerances, putting something as thick as Lucas in could very well make your problem worse. Motor Honey and Lucas might as well be the same product, they claim the same things. If you have a problem with start-up engine knock, maybe you might try using a block cleaner to the oil just before you change the oil and filter. I've used K+W brand block cleaner. I've also tried the trick of driving with one quart of Dexron-Mercon substituted for one quart of oil, and then driving for 3000 miles on that. The tranny fluid is more highly detergent than regular motor oil and is supposed to help clean out gunk build-up. I experienced no problems and I seemed to have gotten more crud out the next oil change. I would definitely stick with ACDelco filters or WiX as was already suggested. One last item, do you drive far enough to get the engine up to operating temperature, Maybe short driving trips are causing sludge buildup in your engine, then oil starvation happens, thereby causing a knock. -Chris

Sounds like "Piston Slap" to me. This excert is from another website I found;

"There've been a lot of complaints about cold-start knock in the Vortec engine family, and most General Motor's customers are getting incomplete answers at dealerships. We've spoken with Matt Kester, assistant manager with GM Powertrain Product Communications, about the situation. He said General Motor's engineers are aware of the problem and are currently in a research stage. The cold-start knock involves the 4.8L, 5.3L, and 6.0L V-8s in all applicable GM cars and trucks from '99 to '02. They believe the cause is carbon buildup on the circumference of the piston above the top piston ring. This interference is affecting the dynamics of piston travel and therefore causing a knock. It seems the problem begins after the first 12,000 to 15,000 miles, and the knock will last between five and 30 seconds in temperatures below 50* after a cold startup. The noise also seems more pronounced after long trips and at lower temperatures. The use of a top engine cleaner will give only temporary results, if any, and a replacement engine without modifications would most likely develop similar symptoms. We were also told that a Technical Service Bulletin is in the process of publication, which should provide an explanation of the condition but not a fix, and that carbon deposits and associated knock are not causing any structural damage to the engine. So, for now, don't let it bother you. We'll give you further details when the TSB becomes available."

Here is the TSB from GM;

Info - Engine Knock on Cold Start #01-06-01-028A - (03/18/2003)
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.

Check out this website for some more info, it is a very common GM problem.

http://www.pistonslap.com/

thanks for some info guys ,spitanddirt my truck has 90000 mile on it ,i only use it when i go out with my family,that about maybe once a week. sometimes longer than that ,the rest of the time it just sits there.

one more question ,when i put it into gear sounds like the u-joint makes a clunk noice ,but i whent under there and it seems ok. there is no play in the drive line at all .any help is welcomed

thank for the help guys :banghead:

I had been reading about the rear diff twisting from the applied load. The sound was created from either the springs or the severe misalignment of the the rear u-joint. Have a friend put the truck in and out of gear and you listen from underneath. Pay close attention to the drive shaft and the leaf springs moving. Hope this gives you some ideas-Chris

thanks chris for taking the time,its my first time posting here and all you guys been helpful thanks again and i will try what you said


thanks :lol2:

That piston slap article did say "no structural damage to the engine", right?