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Engine Noise ~ NOT ON START UP ~


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Sep 23, 2002
Emporia, Indiana
I have searched and can only find threads about the tapping noise on start up. Mine has been making a tapping noise since it was almost new. It does not do it on start up but rather after it has warmed up. I first noticed it while in a line at a dive up window. You could hear it echo off of the building.
This sounds like a lifter noise. I had a Vortex Muffler put on a few days ago and the muffler guy let me watch as he started the AV and raised it back up on the lift to check for leaks. We noticed the noise a lot more from under the AV and it sounded like there were two tapping noises, one from the bottom of each side of the engine! They are not a knock, just a tapping sound. They don't seem to be getting any louder (about 9,000 MILES)
I have taken my service manager out to listen to it at least twice and he just says "Yea, these engines are not as quite as they used to be"
Sorry for the long post but I want to know if anyone else is having this noise. I have read about some users changing their PCV valve. Did that cause any tapping noise?
Kind of a lame answer from the Service Manager....

I havent noticed a noise on mine yet but I will keep and ear out for it.

Let us know what you get resolved.

Happy modding
There is a service bulletin covering this problem, I will get the number for you. Basically, the o-ring on the oil pickup may be cut allowing the oil pump to suck air and bleed the pressure off. As long as you have the complaint documented the dealer should take care of it. I know it covers the 5.3 and 6.0 engines in most GM vehicles. :0:
Has anyone else had to replace their oil pump O ring? What kind of noise was your engine making before you replaced it? Did the O ring fix the noise problem?
Ramz3 said:
TSB 02-06-01-038 dated 12-02-02

I looked on AllData and it did not list this TSB. Can someone find this and give me a link so I can print it out to take to my dealer?

Ramz3 said:
There is a service bulletin covering this problem, I will get the number for you. Basically, the o-ring on the oil pickup may be cut allowing the oil pump to suck air and bleed the pressure off. As long as you have the complaint documented the dealer should take care of it. I know it covers the 5.3 and 6.0 engines in most GM vehicles. :0:

I want to thank Ramz3 for sending me the TSB on this problem. I have been fighting the dealer for almost a year on this, he just says it is normal. I have heard enough 5.3's to know that it is not normal. This TSB discribes my problem to a T! I am going to make a trip to the dealer tomorrow and see what he has to say now. If I get them to replace to O ring on the oil pump pick up and it fixes the tapping noise I will call GM and try to get them to extend my engine warranty, after all it has been running short on oil for almost a year!
I didn't have this problem, but a friend of mine with a new Sierra with the 5.3L had what appears to be the same problem you are describing. At about 1000-1500 miles, he started to notice the "tapping" noise when the truck was warmed up. There was no noise when it was initially started.

He had to bring his truck back to the dealership 4-5 times before they finally determined that it was a problem with the o-ring in the oil pick-up tube. They replaced the o-ring and he hasn't had any further problems.

(He was lucky that there was only about a 7-10 day period and about 300 miles of operation between the time he first noticed the noise and it was finally repaired)

I have the same problem...have noticed the tapping almost since the day I picked it up...similarly mine is also very noticeable going through a drive-thru...have 6K miles on now.

Had shop listen but they said only could here injectors.

I need to locate a copy of this TSB also.
The TSB is to large to attach here, If you will send me your E-Mail address I will send it to you. Send me a private message if you want.

I have an appointment on Monday afternoon to get this problem checked out. I will let you know what they find. I have myself convinced that this is the problem but we will see.
My buddy got his Tahoe back after the Oring surgery yesterday, it purrs quietly, no more tapping.
Ramz3 said:
My buddy got his Tahoe back after the Oring surgery yesterday, it purrs quietly, no more tapping.

Thanks, great news! I take mine in Monday and only hope that this is the problem so I will be done with it!
? ?I took my 02' Z66 with 8800 miles in today for the tapping noise in the engine. I had the oil changed and tires rotated also. I had the TSB in hand and had told them about it when I called to make the appointment.
? ?We left it and went to lunch. When we got back about 1 1/2 hours later it was setting outside. The service writer said they did not hear any unusual noise. It did not surprise me as it kind of come and goes. I pay for the tire rotation and the oil change and go out and start it up and get out to see if I can hear the tapping. I hear nothing. I drove the 12 miles home and when I pulled into the garage I again hear it!
? ? I left it running and got out and put my ear down by the wheel well and you could hear a tapping noise, not to loud, but it was there. Well I took it right back to the dealer.
? ? They were fair about it and seemed interested. I ask if they had changed the oil BEFORE listing for the tapping noise and found out that they had. Well the TSB said that the split O Ring lets the oil airate so I thought that is why they did not hear any noise, they had drained out the aireted oil and put in new before checking it out!
? ? The dealership had just built a new building and moved in last week. They put my AV on a lift and let me be there with them. I could hear a tapping noise at idle, but it was not to loud. The service writer went and got the service manager and he, in turn went and got two mechanics. We were all listing under the AV for a good 10 min. They all said that it is a normal sound and that they are just noiser than they used to be!
? ? I was still skeptical and told them that my brother had a new Yucon XL with the 5.3 and it does not sound like that. The mechanics said that at least 90% of the 5.3's sound just like mine. ?We all talked for a while longer and the service manager said, well wait just a min longer and he left. He brought in his 1500 Silverado with the 5.3 engine and put it up on the lift right next to mine. I could not believe it, but it sounded just the same!!
? ? He said if I was not happy he would do the O ring change but he and the mechanics were all sure that it would not change the sound I was hearing. They said that with all the plastic and aluminum in the newer GM engines that this is normal. I didn't want them doing anything to my AV that would not help it so I passed on their offer. They say they do get lots of complaints of noise in the newer motors but they have seen many with well over 100,000 miles and no problems when they get older and the noise does not get any worse.
? ? To be fair, you can not hear the noise from under the hood. I notice it most when I am pulled right up next to a building, like at a drive up window. You can hear it by listening at the wheel wells after the engine is warmed up. They said if the O ring is sucking air you will hear the lifters get real loud and can hear it with the hood raised.
? ?I have it documented on three invoices from the dealer so for now I am letting it ride. I would be interested if some of you have heard the noise I am talking about. If you let the engine warm up and listen close at the front wheel wells you should hear a tapping sound coming from the engine. Not overwelming, just a light tap tap tap, like a lifter making a little noise. Sometimes you might hear it while at the drive up window at your bank or favorite
fast food joint. ?:6:
Whatever happened? My 03 5.3 with 50.5K miles is making noise at idle. Loud on start up but still present when warm. Sounds like lifter noise but not sure. Will use my stethescope tonight to see if I can track it down. Oil pressure normal.
Found the problem. Changed belt in October when up-grading to Caddy Alternator. Used a Dayco Top Cog 5060945. Found a 4 inch chunk of grooves missing :mad:
Replaced belt with spare and ordered Gates belt. Noise all gone :love:
Interesting indeed.

These TSB's are listed on the board HERE.

#00-06-01-023B: Info - Engine/Balance Shaft Rattle Noise - (Nov 26, 2002) (In 2002 part 1)
#02-06-01-038:  Engine Knock or Lifter Noise (Replace O-Ring) - (Dec 2, 2002) (In 2002 part 2).
For me soon after this episode at the dealer I ran 2 cans of Berrymans injector cleaner through a tank of gas. The noise all but went away! I am at 43,000 miles now and its quieter that it was then. I run 2 cans of that injector cleaner through it about 2-3 times a year. I think it was a noisy injector.