Engine Noise Complaint — 2008 Silverado 5.3L LY5
This truck came in just as I arrived at the shop to open for the day, the truck owner was in a bit of a panic mode. I asked about his concern, and he gave me a list of things that mostly made zero sense to me. He stated that he was trying to get to a job site and was from a town that is about 30 miles away and was afraid to try to drive it back there to get it checked.
His concern was that the engine had a noise all of a sudden that was never there before, then he stated that prior to the noise, the engine light came on but was running normally. He said he pulled over, shut the truck off, restarted the truck and the engine light was off and hasn't came back on, but now he has the noise and the transmission is running hot.
I went out to the truck to get the vehicle information, at which time he insisted that I listen to the noise. (I had already informed him that I couldn't check it out for a couple hours at least), so while I was there, I had him start it so I could listen, it had what sounded like a deep internal ticking. He then said, see, the transmission temperature is hot. I looked at the driver information center and noticed the transmission temp was only 136 degrees F.
When the time came to check the truck out, I shared what I was told with Nate and asked him to bring it in without a test drive and to check for codes. After checking fluid levels, Nate reported that only P0300 was stored, so I suggested checking the generic side for possible cylinder specific code(s), he then collected P0304. Nate listened under the hood and determined the noise was on the right bank, I suggested that he do an in cylinder test on two cylinders, one on each bank.
There are many tests that we could do in several various orders, I am a small shop with limited time to spend testing, so we went in cylinder. Simple/quick/accurate.
1st sample, cylinder 1.
Next, we analyzed cylinder 4, which is abnormal. I told Nate what the waveform indicated to me, and that is, that we had a collapsed intake lifter on cyl 4, and what indicated that to me.
Here is a short video demonstrating the collapsed lifter.
Hopefully this is written in such a way to be beneficial to everybody. Thanks for taking time to read this!
Great write up rusty . sometimes when you don’t have a known good, it’s always so simple to get a waveform from a working cylinder on the other bank . I see that dip on the Intake stroke much more deep . And also higher compression . all due to he intake valve not opening right ?
Nice write up Rusty.
Late open and early close. What were you circling on the exhaust opening?
There is a little bump in that slope also, seems to be in most of the traces, I believe that lifter is beginning to fail also.
Agreed. I have noticed the bump in exhaust opening pattern as the norm in these engines to varied degrees.
Great diagnosis with awesome pictures and video I have had a few broken valve springs on these motors and have the same issue now like yours but waveform looks good even removed valve cover to visually inspect lifter movement need to go deeper
Hope all is well. I just read your write up, Very Nice.
I just wanted you to know that I have had very good success fixing these GM 5.3L liter problems with ATS Chemical 505CRO oil treatment. I have fixed over 12 of these engines with lifter problems with no tear down. Put the oil treatment in the vehicle and drive it for about 30 minutes, then change the oil and filter. On one of these engine I had to leave the oil treatment in much longer. I drove the vehicle home and the next morning when the engine was started it was fixed. These lifters are prone to carbon build up (sludge) that sticks the locking pin. Once the carbon is removed the locking pin moves back in to lock the lifter.
Awesome Bernie! Thanks for sharing that with me! I have been selling some of those, mostly on excessive useage or start up smoking. Works extremely well! I will try it on the next one of these I get.
I have used this chemical in a few bmws and have fixed vanos issues awesome product ATS did it again thank you Bernie your friend Eric ….
Nicely done Rusty and nice write up! Thanks for sharing
Our experience with the same year and engine on two occasions was the same cylinder but a wiped cam lobe due to a faulty lifter roller.
Yeah, would have a completely different waveform though.
There is something I have been wanting to try with items like this, noises in particular. Using the in cylinder pattern in conjunction with an ultrasonic noise detector like the Inficon Whisper. These detect noise outside of normal human hearing and have some impressive capabilities. Normally used with headphones and well beyond the capability of a typical stethoscope. They not only work with headphones but also output a waveform that can be displayed on a scope.
The theory I have works like this. You have your cylinder profile that sets one specific engine position. The noise of interest is flagged in the Whisper output and the position is noted based on the known rotation from the pressure transducer. The number of cylinders is used with measurements to identify the internal component moving or in the case of a rod, piston etc changing direction. Then the likely cause of the noise is calculated to the component cylinder.....
Edited to add that the CKP pattern may also be used.....
I like that Idea.
I have already made a piezo stethoscope with a probe end. I feel a quick synch on cyl.1 is more than accurate enough. I was picking up every firing event, but was having a hard time picking out valve train noise. My next project will be an ear/horn type piezo stethoscope. See what I can pick up with that. Let me know how the ultrasonic tester goes.
Interesting! I certainly don't have any experience in that, but sounds like it could be very useful!
Hey Rusty great find! I'm just getting started in the world of in cylinder pressure transducers. I like to look at these captures and try to decipher myself what is going on in the cylinder but I find myself over looking or not spotting "hick ups" in the capture. So i notice that cylinder# 4 has higher compression the cylinder events are shifted a lil from the cursors and notice the large pocket on the intake, but whats wrong with the decompression pocket you circled?
I should have posted one without the divisions on it, if you look closely at that ramp, you can see a bump similar to a pintle hump on an injector current ramp, I believe that indicates the other lifter is beginning to have issues as well.
The bump on the exhaust pocket is normal on these engines. What is different with the collapsed lifter is in the intake position of the waveform. Notice that the intake drop is late after the 360 degree point. The pressure drop also takes longer to occur due to the lifter not opening the valve as rapidly as it should. At the 560 degree point (BTC) the pressure is starting to rise, this is due to the valve closing too early due to the lifter. The valve should be open at this point and not close until 50 degrees after BTC, thus allowing the pressure to increase.