2000 5.3 knock, help diagnosing cause?

[LeakySeals]

Originally Posted By: Snagglefoot
Originally Posted By: LeakySeals
Originally Posted By: Snagglefoot
It's worth trying 5-30 oil and a Fram Ultra. What was the temperature the morning you started it? I heard it was a bit cold in your part of the woods lately.


I stopped using the Ultra on my 6.0 because piston slap got worse. I tried a better flowing lower efficiency filter and that helped a lot.


Interesting. Wondering, did you changed the type or weight of oil at the same time. IE: changing two parameters in stead of one? Also, can you tell us which filter gave you the better results? Thanks.

Stuck with the oil in my sig for the test.





The only variable changed was the filter. Started happening after an oil change last year. I did a hot swap with a spare Fram TG. Topped off. Gone! I figured it might be a one-off so I went back to the Ultra next oil change. Back came the slap. Swapped to the TG again, gone. So now I just stay with the TG. I don't know what changed last year, but I can't use that filter on my 6.0 anymore.

 

[LeakySeals]

Would appear having good flow at startup keeps cold pistons from wiggling around as much.

 

[Mc357]

Originally Posted By: Snagglefoot
Originally Posted By: Mc357
I did add a quart or Marvel's it did not help yet. I'm hoping it's just a small clog, and will soon flow better .
But as others have said it may be piston slap and nothing will cure it.


I wouldn't chalk it up to piston slap. When you bought the truck it was quieter, correct? I'm guessing the problem showed up with the colder weather. Would that be right?


Exactly. The guy I bought it from said it ticks when cold sometimes. But it didn't seem so bad as it is now that temps have dropped.

 

[Trav]

Originally Posted By: Mc357
Originally Posted By: LeakySeals
I thought that problem was limited to the 5.3 w/AFM. Guess not, thats the noise.. a lifter gouging a cam lobe.. Gotta fix it, can't live with.

Is there a check engine light on?

The check engine light comes on if I keep it above 2000 RPMs for very long so if I go down the highway and I go over 70 I will get a flashing check engine then it stays solid if it's very cold out and I'm going 35 or 40 I will also get a check engine if the RPMs go above 2000 for more than a few seconds the code is p0300 random multiple misfire.
I just put new iridium ac Delco in and it did not help


First thing to check is the cat(s) before going any further. A plugged cat(s) can cause all sorts of noises from the engine.
Forget the oil for now, that's not doing much good, spark plugs and snake oil either.

 

[Snagglefoot]

Sounds like Delo 10-30 is a logical choice. It has a higher level of detergent and surfactent. Being a mixed fleet oil the zinc is not unusually high, somewhere around 750 ppm. The higher temperatures coming shortly might mask the results so maybe wait until its warmer before you do the change. Leakyseals mentioned that the Fram TG helped. Keep us posted as lots of folks have the same problem.

https://cglapps.chevron.com/msdspds

 

[Snagglefoot]

Originally Posted By: LeakySeals
Originally Posted By: Snagglefoot
Originally Posted By: LeakySeals
Originally Posted By: Snagglefoot
It's worth trying 5-30 oil and a Fram Ultra. What was the temperature the morning you started it? I heard it was a bit cold in your part of the woods lately.


I stopped using the Ultra on my 6.0 because piston slap got worse. I tried a better flowing lower efficiency filter and that helped a lot.


Interesting. Wondering, did you changed the type or weight of oil at the same time. IE: changing two parameters in stead of one? Also, can you tell us which filter gave you the better results? Thanks.

Stuck with the oil in my sig for the test.





The only variable changed was the filter. Started happening after an oil change last year. I did a hot swap with a spare Fram TG. Topped off. Gone! I figured it might be a one-off so I went back to the Ultra next oil change. Back came the slap. Swapped to the TG again, gone. So now I just stay with the TG. I don't know what changed last year, but I can't use that filter on my 6.0 anymore.


That's real interesting. Thanks for sharing that.

 

[Mc357]

Originally Posted By: Snagglefoot
Sounds like Delo 10-30 is a logical choice. It has a higher level of detergent and surfactent. Being a mixed fleet oil the zinc is not unusually high, somewhere around 750 ppm. The higher temperatures coming shortly might mask the results so maybe wait until its warmer before you do the change. Leakyseals mentioned that the Fram TG helped. Keep us posted as lots of folks have the same problem.

https://cglapps.chevron.com/msdspds


I was thinking the same thing, delo should have the detergents that may help if it is some piece of sludge blocking a passage.

I have read a lot of problems, but mine just seems louder than piston slap. I had an 01 with 275k miles and it had a lifter tick, and it was less of a deep knock sound.

my oil pressure gauge also jumps around a bit while i am driving sometimes.

I do hope it is piston slap, not some sort of major failure.

 

[LeakySeals]

Originally Posted By: Snagglefoot
Originally Posted By: LeakySeals

The only variable changed was the filter. Started happening after an oil change last year. I did a hot swap with a spare Fram TG. Topped off. Gone! I figured it might be a one-off so I went back to the Ultra next oil change. Back came the slap. Swapped to the TG again, gone. So now I just stay with the TG. I don't know what changed last year, but I can't use that filter on my 6.0 anymore.


That's real interesting. Thanks for sharing that.

No problem. I'm not bashing the Ultra in general, I like that filter. Just not on this 6.0, it likes something else.

 

[Mc357]

Originally Posted By: Trav
Originally Posted By: Mc357
Originally Posted By: LeakySeals
I thought that problem was limited to the 5.3 w/AFM. Guess not, thats the noise.. a lifter gouging a cam lobe.. Gotta fix it, can't live with.

Is there a check engine light on?

The check engine light comes on if I keep it above 2000 RPMs for very long so if I go down the highway and I go over 70 I will get a flashing check engine then it stays solid if it's very cold out and I'm going 35 or 40 I will also get a check engine if the RPMs go above 2000 for more than a few seconds the code is p0300 random multiple misfire.
I just put new iridium ac Delco in and it did not help


First thing to check is the cat(s) before going any further. A plugged cat(s) can cause all sorts of noises from the engine.
Forget the oil for now, that's not doing much good, spark plugs and snake oil either.


I do not get any 02 sensor codes, and the truck seems to run well otherwise, even when it does misfire, i can not feel it happening. it feels like it has the power it should.

 

[Oldmoparguy1]

Interesting problem. I had something similar in an old Chrysler 3.8 V6. Changed to Rotella T-6, 5w-40 and it mostly cleared up. If it were mine, I would change the oil to Rotella T-3 15w-40. Just change the oil, leave the filter on. If the noise gets better it would point you to something like piston slap. If not, no harm done. Doing so would be a cheap diagnostic. Good luck.

 

[demarpaint]

I'm not seeing how an oil or a filter change is fixing it, sorry.

 

[RedOakRanch]

I had heavy piston slap on cold mornings for a few years. BC0w30 and a napa gold has fixed it, no slap in the last 20k miles. I didn't even try to fix it, just lucked out.

 

[Trav]

Originally Posted By: Mc357


I do not get any 02 sensor codes, and the truck seems to run well otherwise, even when it does misfire, i can not feel it happening. it feels like it has the power it should.


Why would you have O2 codes in open loop? When warm the mixture is much leaner and a partially plugged cat will let some of gasses through, if it were totally plugged it would stall.

 

[Mc357]

How would I find out if it we're a partial plugged cat? I did pass CT emissions not long ago.
Do you know what temp the fuel ratio changes? I can keep an eye on temp to see exactly when the knocking stops.

 

[Mc357]

Originally Posted By: RedOakRanch
I had heavy piston slap on cold mornings for a few years. BC0w30 and a napa gold has fixed it, no slap in the last 20k miles. I didn't even try to fix it, just lucked out.


Did yours sound the same as mine? Mobil 1 makes a 0w30 too

 

[Trav]

Originally Posted By: Mc357
How would I find out if it we're a partial plugged cat? I did pass CT emissions not long ago.
Do you know what temp the fuel ratio changes? I can keep an eye on temp to see exactly when the knocking stops.


Vacuum gauge/back pressure gauge or pull the front O2 sensors or drop the pipes off the manifolds. If there is a noticeable change you know where to look further.

 

[FermeLaPorte]

Just get a good oil 5w-40 oil

 

[AVB]

Originally Posted By: Trav
Originally Posted By: Mc357
Originally Posted By: LeakySeals
I thought that problem was limited to the 5.3 w/AFM. Guess not, thats the noise.. a lifter gouging a cam lobe.. Gotta fix it, can't live with.

Is there a check engine light on?

The check engine light comes on if I keep it above 2000 RPMs for very long so if I go down the highway and I go over 70 I will get a flashing check engine then it stays solid if it's very cold out and I'm going 35 or 40 I will also get a check engine if the RPMs go above 2000 for more than a few seconds the code is p0300 random multiple misfire.
I just put new iridium ac Delco in and it did not help


First thing to check is the cat(s) before going any further. A plugged cat(s) can cause all sorts of noises from the engine.
Forget the oil for now, that's not doing much good, spark plugs and snake oil either.

That was the problem on my 2003 Avalanche 5.3. It had noise at start up, it sounded like it was coming from the engine. I got under the truck and beat on the cats, you could hear them rattle.

 

[clinebarger]

That's Piston Slap. Some LS engines are really loud when it's cold!

Like Trav already stated......Fix the misfiring! Your going to ruin the converters if their not already the cause of the misfiring. A flashing MIL means the converters are being harmed.

These trucks generally set a P0101 "MAF sensor out of range/sensor performance" when the converter/s get plugged/partially plugged. But not 100% of the time.

Did you replace the plug wires?
Have the Catalytic Converters checked. You can make a Vacuum/Pressure gauge adapter out of an old O2 sensor.
Check Fuel Pressure.
Check for Fuel present at the fuel pressure regulator vacuum hose.
Spray some carb cleaner around the base of the intake (Where it meets each cylinder head) on a cold start.....If the RPM's change dramatically or makes it run rough, Change the Intake gaskets. They leak when is cold & will not necessarily cause "lean" codes.

Do you have a way to isolate the cylinders that are misfiring? Capable scan tool to watch/log misfire data?
While the Multec II injectors on your truck are not near as bad as the original Multec injectors......Their performance still degrades over time/mileage especially if it sits a lot. I think Trav checks & flows Injectors?

 

[Georgiey22]

I owned a 99 Silverado with a 5.3 and here is what stopped startup slap for me. Switched to M1 0W30 AFE with a Napa Gold Filter. Has 140K and purrs like a puppy. Gave it to my Uncle and he uses it as his work truck. Hope this helps.