Start Knock....

knightrider2000 · March 30, 2003

Hey All,

My 99 Silverado with the 5.3 has started a nock/tick problem, almost like a lifter has leaked down, it quits after about 10 seconds of idling, usually only does it after truck has sat for about 4 hours or longer.. Is this what they are calling the famous cold start knock? Would an engine cleaner, that you put in your oil, possibly help?

Thanks!

Matt

Stepside Z · March 30, 2003

Sounds like the problem previously described. I am not sure that GM has a fix for it yet.

Blue Ghost · March 30, 2003

The cold engine tick that most 99-02 trucks have is caused by a design change in later model engines (they have removed the piston skirt to reduce rotating weight) which most have seen was a pretty lame idea, they claim this noise causes no engine damage and does not shorten engine longevity, which seems to be true (I have seen quite a few with over 200,000 miles)it's is just plain annoying

The second cause is when these engines start to get some miles accumulated, the oil entering the PVC sytem starts to bulid up carbon on the valves and pistons,the repair for this is to use a top engine cleaner that is put into the engine through a vacuum source(the booster hose) it it is best to get this product from you local GM dealer for best results,or have one perform this procedure for you (if you decide to do this yourself e-mail me I can give you pointers for best results)

Sorry for the rant,hope that helps

knightrider2000 · March 30, 2003

I was thinking of using a product called "Sea Foam" (any good??) through one of my vaccum lines. But would appericate any pointers you could give..

Matt

Blue Ghost · March 30, 2003

Matt, I have heard of using the product "sea foam" for cleaning the lubrication system but dont know how it works or if it is meant for carbon removal.

When using GM "Top engine cleaner" you want to get the engine up to full operating temp, have someone hold rpms around 2500 without letting it stall out as you add the cleaner into the vacuum system (a small funnel works well in the booster hose) or through the throttle body on early engines (slowly add the cleaner as not to flood the engine), as you reach the bottom of the can try to stall the engine with the last bit of cleaner or have your helper cut the engine off as you add the last bit, Now, the most important part is to let that last bit soak into the carbon thats in engine for approx 20min or more if wanted (dont let the engine get cold),after the wait period warm the engine and do as the say with a rental car, DRIVE IT LIKE YOU STOLE IT!! to blow out the loosend carbon.

As you will find out this will cause the vehicle to "smoke like a freight train" while cleaning, so PLEASE do this in a well ventalated area!

Also, when adding that "last bit" of cleaner I talked about dont go overboard and add so much that it floods the spark plugs or hydo-locks the engine!

Best of luck, Derek :thumb:

Disclaimer.... apply at your own risk, not responsible for problems that could occur

knightrider2000 · March 31, 2003

Just curious, how much is the cleaner at GM? Sounds pretty easy.. another question... i have installed a vaccum gauge, hooked it up on the very top of the intake.. it has a small line.. could i just take this line off and put it in the bottle, and let it suck it out? or would that be sucking it to fast?

Thanks!

Matt

Shaners · March 31, 2003

I would call GM customer service, and see if you can't get a free extended warranty on the engine. Several people have had good luck getting GM to extend the warranty on the engine to 100K miles.

the top end cleaner should work, but most likely, the knock will eventually come back...

knightrider2000 · March 31, 2003

I think i will try that, shanners.. Do you have a number i should call to check on getting one? i am going to try the top engine cleaner this afternoon, when the engine is warm, and let it set for about 5 minutes.. would still like to have the ext warrenty though

Matt