Scotty I bought a new Chevy hd truck last year and now after it’s 3rd oil change it’s making the dreaded “typewriter” tick out of nowhere. Wondering if this is an issue I should worry about or just take GM’s word for it and just live with it? They’ve had a bulletin out for these trucks and can’t believe this is a noise people should just live with. Hopping you could shed some expert insight to why this noise happens and if GM is telling the truth about it not effecting the engine reliability.
The ticking is at its loudest point near the oil pan right next to where the transmission bolts to the engine. I have a video of it, not sure how to post it on this forum. But it is an irregular noise that does increase repitition with RPM but does not imitate RPM at idle.
where is the ticking coming from? Maybe it's just the injectors.
https://www.youtube.com/watch?v=U927cYhQXB4
not sure how to post it on this forum.
See the "READ THIS FIRST - Forum Guide" topic near the top of the home page.
sounds nasty. What does GM say causes it? Do you have a link to the bulletin?
GM says that typewriter clicking sound is normal? Unbelievable...
What's worse is that no noise on factory oil, or after the first 2 oil changes just happens to appear after 3rd one?
https://acrobat.adobe.com/link/review?uri=urn:aaid:scds:US:67cb07b1-d918-33eb-874c-eb2b233d4069
GM Bulletin for L5P typewriter tick as normal.
this bulletin was printed for me at each dealership with updated manufacture dates.
The ticking is at its loudest point near the oil pan
"DEF Injector Noise: A tick noise may be heard coming from under the vehicle and typically it is heard at low vehicle speed and especially next to a building, such as when going through a drive through. The noise is from the DEF Injector and is considered a normal operating condition."
Is this what the dealership told you was the source of your noise?
GM Bulletin for L5P typewriter tick as normal.
Hm, interesting. To some degree, GM must be right. I don't think they would make such an official public document like this unless there was some truth to it. Otherwise, if it was later found out the engines had a serious and common flaw which caused this noise (for instance by a mechanic who tore an engine down and found evidence), then that would look really bad. GM could be accused of negligence and trying to cover it up.
But I have a different issue with this bulletin. It's too ambiguous. Let's say an engine had a legitimate defect, and it made a noise that could be described by the very vague term "tick". This bulletin is a basically a free pass for dealerships (who have an incentive to avoid warranty works as much as possible) to sweep any noisy engine problem under the rug.
I think GM should have included very thorough diagnostic procedures to sort out which reports of noise are in fact benign, and which could be symptom of a real problem that needs to be addressed.
you may want to seek the professional opinion of a non-GM affiliated mechanic. One who is very experienced with modern diesel engines.
Owned a diesel Mercedes 240D once and I've operated diesel tractors, this noise still surprised me. Yes, a diesel will typically sound louder than a gasoline engine, but this noise "started'' after his 3rd oil change??? That in itself seems strange to me. I agree @imperator , "It's too ambiguous"
Ford has a similar issue with their Coyote 5.0 engines (typewriter tick) that shows up after the first oil change. Some engines are affected. some are not.
Something is going on with these newer engine designs. I have yet to see anyone tear down one of these motors and determine if there really is an issue or not.
Since the typewriter tick is not present in a brand new engine until the oil has been changed, GM and Ford are not being entirely truthful. What is changing after the oil change? Is the oil they use from the factory masking it?
I'm guessing their engineers know what the issue is, and it's a small enough problem that engine longevity isn't affected (from their perspective at least).
