More about Engine noise...

Kamyoon · July 28, 2003

I contacted my dealership about the engine noise and they gave me the normal stealership hassel. First they couldn't hear anything (while parking and running the car next to their facility's AC unit)!! After we moved the car, sure enough it was there. Then they gave me the bit about carbon tick, and the need to have the injectors cleaned...told them I have done that already!!...Then they said it will cost me $450 to run some kind of engine cleaner through the spark-plug holes, leting it sit overnight, and that should take care of it. But no Mr. Goodwrench garauntees ...And that basically meant we do not want your bussiness and do not want to deal with your problem.

There are a few e-mail on their way to the "GM whomever" as we speak. Hopefully I'll get a response

While listening to the noise I noticed that:

1- The noise comes on about 30sec to a minute after I turn on the engine.

2- When I start up, the oil pressure gage is above 55.

3- When the gage pressure drops to about 40 to 45, it starts ticking.

4- When I rev the engine, the pressure goes up to above 60 and the tick goes away.

5- leting of the gas, pressure stays above 50 for about a minute or so and there is no ticking.

6- As soon as the pressure drops in the 40 to 45 range, the ticking starts again.

7- I have changed the oil and filled with 6 qrts of 5W-40 Syn. and the same thing repeated again. Dip-stick shows oil level is in the high opertaing range.

Does this mean anything? Could it be an oil pump problem? The truck doesn't burn oil or show any indication of leak or etc.

This is a 4.8L GMC Sierra 2000 with 59K on it.

Any help on this will be greatly appreciated....

Shaners · July 28, 2003

I have heard that there are some issues with an oil pump O-Ring that can cause a "ticking" sound...

Good Luck...

JonesNTN · July 28, 2003

What are your RPM's during all of this? Is it possible your valve springs are causing all of the noise?

Kamyoon · July 29, 2003

Aside from when I rev the engine up to 2500 rpm, the ingine is just idling. When I rev the engine, the frequency of the ticking noise goes up and then disappears. After I let off, the oil pressure stay high for a while and no noise. Then when it drops, the ticking starts.

I just found a TSB for the O-ring issue. I am going to check it out to see if that is the problem. If you have gone through this before, let me know how should go about getting to this O-ring.

Thanks for your responses.

Kamyoon · July 29, 2003

How can you tell the difference between valve spring noise and this piston slap business that every body is posting about?

If it is valve springs, what is the solution?

The guy from dealership recommanded doing 90MPH on the highway to burn up the carbon build-up!!

I am a newbie to all of this piston-slap and valve noise issues. Is carbon build-up what creates valve spring noise? If not, what is the cause, and how can it be cured?

bassdog · July 29, 2003

I have the clicking noise as well, dealer is replacing the oil pump o-ring late next week. The clicking is coming from the lower end near the oil pan.

WEFs99 · July 29, 2003

I've been told that mine (5.3) is piston slap but it sure sounds like old fashioned lifter noise to me. Kamyoon, yours definitely sounds like a lifter because it is affected by pressure.

2001 HD · July 29, 2003

Bassdog-Please give us a report after the o-ring replacement. I've seen this TSB, but have been sceptical that this is the problem. But the CSK does seem to improve right after an oil change. And the guys over on LS1Tech.com are having problems replacing o-rings and they seem to slip out of place during installation and get sucked into the pump.

SilveradoWV · July 29, 2003

My 4.8L does the same thing, actually its not a big deal to me!! But if anyone finds a cure please pass it along!

Lester · September 22, 2003

has anyone for grins tried heavier weight oil on one oil change i.e. 10W-30?

AZ-Z71 · September 22, 2003

Difference between the valve spring noise and the piston slap is that the piston slap usually does it on the first start in the morning when the engione is cool and goes away after about 10 seconds.

jhm · September 23, 2003

Difference between the valve spring noise and the piston slap is that the piston slap usually does it on the first start in the morning when the engione is cool and goes away after about 10 seconds.

The dreaded piston slap!! This noise can appear under any conditions. Mine is super quiet when cold, no noise period. After I start accelerating I hear a definate metal to metal ping type noise. Truck has had 3 tests on analyzer and they say everthing is perfect, just "normal piston slap" that I dont need to worry about, at least I got the extended warranty from GM for free, guess I will drive into the ground!

dukbludvl · September 23, 2003

i run 10w-30 in my yukon during the hotter summer months and 5w-30 during the winter.

could it be that you have a compression problem? have you changed the spark plugs recently? when i last changed mine, i didn't get one of them in there tight and the engine made a ticking sound until I found the loose one and tightened it up.