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Chevrolet 5.3 LS engine Rocker Arm/Pushrod Problem

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13K views 8 replies 5 participants last post by  Procharged GTA  
#1 ·
My dad's is currently working on a 2004 Chevrolet Avalanche with a 5.3 LS engine with 170,000 miles and the customer brought it for him to check out, because he said it just recently had started a "chirping" noise that sounded like belt tensioners, so he replaced those with new ones, and it did not cure the problem. Upon further inspection, he found that all of the rocker arms are worn pretty bad, as well as the ball tips on the pushrods, but there is NO evidence of blueing from high heat or anything, and they are not "dry", so it appears that this isn't an oiling issue, and as soon as it fires up, the gauge in the truck shows 30-40 lbs oil pressure to confirm it. I have read that the LS engine do have some valvetrain problems.... and he is thinking about replacing the rockers and pushrods with new ones, along with new oil and filter, and use a good synthetic oil... but he is hoping that it doesn't ruin the new rockers and pushrods if there is some other problem.

My question is, are the LS style motors inherent for wearing the rocker arm and pushrods as I have described? If so, then a new ones should last a long time again....

Thank
 
#3 · (Edited)
Thanks! That makes alot of sense, I've been talking to a couple people on the phone this morning too that has told me the same thing, and they also warned me about and o-ring that's behind the camshaft retainer plate? And also the cam bearings are known for giving problems? We don't have a whole lot of experience with the LS engine.... yet Lol, sounds like it may not be long if the customer wants it fixed....

Thanks!
 
L
#5 ·
04/05 5.3 with certain castings let coolant weep into oil and ive seen more then 1 plug up the oil filter. they come in making chirping noises and clacking noises due to lack oil pressure(lifters bled down). some if caught early can be saved and the owners change the oil filters once a month themselves and they trucks have lived a long time like this, other come in and damage to lifters,cam,valvetrain have put metal thru the engine and we replaced the engines.

ive also replaced them with just beat rollers due to lack of proper maintenance
 
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#6 ·
Let me add something to help with your diagnosis to better convince you. Remove the valve covers and start the engine. Take a long screw driver and isolate the chirp by placing the screw driver on each rocker arm bolt and listening. Once you find which one it is, remove the rocker arms from that cylinder, disable the injector and see if the chirp goes away. You may also have a misfire on the chirping cylinder as well.
 
#7 ·
Ok, thanks for all the help, now the customer has decided to buy another used 5.3 and have my dad change the whole engine out, it was delivered to us today. Here is the deal, the used 5.3 he bought is a Flex Fuel motor, and his truck is not a Flex Fuel 5.3, just a standard gasoline 5.3. So my question is, what needs to be changed from his old engine to the used "Flex Fuel" engine we are replacing it with to make it compatible with just gasoline like it currently is? I know the injectors are different.... what else needs to be changed from the old motor to the one to make it work? Thanks! :)
 
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