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GMC 4.3L Valve Noise Help


misterZ

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Help!

 

My `04 GMC Sierra 1500 all of a sudden developed a valve/lifter ticking noise last night when I started it up to run an errand. After driven 4-5 miles the noise subsides and all seems quiet. It happened again this morning on my way to work. I change the oil regularly, the dipstick reads full and I have good oil pressure (~38psi) before and after it's making the sound.

 

My concern is I've never experienced this in the past and the engine is typically very quiet until now. I'm due soon for an oil change (15% usage left) but heard I might try to add Marvel oil and also check to be sure it's not an exhaust/head leak(?)--pushing 180K miles.

 

Thanks in advance,

 

EDIT: CORRECTION 5.3L motor

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Guest Gr8White

Are you positive this is valvetrain noise? Sounds like it might be a leaky manifold or header- (don't know whether you have headers). What happens is the manifold leaks when cold, then expands as it heats up and seals the leak. If you have good oil pressure and a full dipstick I would look for this as a possible cause of your noise. I've had it happen to me and exhaust leaks can sound lvery similar to valvetrain ticking. Just a thought. Get it into the garage in the dark when cold and see if you can see any light exiting the manifolds, if it's minor you might not see anything but it's worth a shot....

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Are you positive this is valvetrain noise?

 

Not positive but everything I read today indicates this is a common occurance in (high mileage) GM & Ford motors related to the hydraulic valvetrain--not enough oil getting to the lifters at start up when the engine is cold. Here is what I captured off the Trailvoy.com forum regarding my engine:

 

 

"What happens is that any lifter that is being 'compressed' by a lobe on the camshaft will tend to 'leak' some of its oil over time. So you turn off the engine with a valve or two being pushed into the open position. Upon startup, it takes a few seconds for the lifter to fully 'prime' back up with oil and you get a faint ticking sound due to the lifter not being full height until this occurs. Provided it isn't the heavy sound of a collapsed lifter and the noise goes away after a few seconds, this shouldn't be a problem."

 

"I talked to one of the outside sales reps from gopher engines in minnesota he said there is a bulletin from the automive engine rebuilders association about there being and o-ring on the oil pump and it causes the oil to drain back causing the lifters to not pump up completely right away."

 

 

So possibly my oil pump is leaking? My noise is not that subtle and quite annoying until the engine is warm. I also read that synthectic oils sometimes resolves the problem or at least quiets the motor--I've been using conventional oil but will switch next oil change. Thanks!

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I've experienced that in a 96 4.3 in my Land Rover conversion. It has only happened a few times over 10 years. The noise is crazy loud until the lifter pumps up. I've never opened the engine to resolve it and it hasn't happened in a couple of years now...go figure.

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Could be an exhaust leak or lifter that quietens down after getting warm...wasn't there a GM TSB on the 4.3 out for excessive carbon build up on the piston dome causing a similar noise? I'll look for that and get back to you.

 

EDIT: n/m just noticed you changed it to 5.3l

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So why post here? You know there is a Gen III and Gen IV forum with people that use that engine. Just curious.

Actually the curious part here is why the Nissan engines in this forum fall under OTHER.

 

Check this out.

http://www.ls1tech.com/forums/generation-iii-internal-engine/1075148-cam-lobe-failure-analyses.html

 

http://www.ls1.com/forums/showthread.php?p=1486333

 

http://answers.edmunds.com/question-Ticking-noise-starting-Chevrolet-Tahoe-14654.aspx

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