LB7: Rotational knocking when engine is warm
- Thread starter SpotlessDemo
- Start date
Thanks for the info Curt and everyone. Curt, I hope mine is just a valve adjustment and nothing like yours. That looks like a nightmare. Short of any other ideas I plan to adjust the valves in about a week or so. I'll keep everyone posted. My money is not on the injector since it definitely sounds like a rotational noise. I have been wrong before, but a poor guy with a diesel doesn't have much more than hope at this point, right?
could you just unplug the injector harness for cyl 5,7 drivers firewall!(maybe even try it with cyl 1,3(drivers side front) unplugged after trying 5,7) @ valve cover and see if noise goes away with engine warm? i understand it will throw codes but might be a quick diagnose to see if its a valve train or injector noise without having the software(efi live/tech2 to isolate injectors?
just my .02 cents! :thumb:
just my .02 cents! :thumb:
Hey Spotless Demolition,
Did you ever figure out the ticking noise? My truck is making that same exact noise at the rear cylinder on the passenger side. I was also told that the injectors had just been replaced when I purchased the truck. The noise is driving me crazy!
Did you ever figure out the ticking noise? My truck is making that same exact noise at the rear cylinder on the passenger side. I was also told that the injectors had just been replaced when I purchased the truck. The noise is driving me crazy!
sorry to burst your bubble but modern vehicals (and i mean mid 80s and above) dont have valves that just go out of adjustment, they use hydrolic lifters that are self adjusting (unless you go aftermarket then solid lifters are available) if a valve is out of adjustment the you have a problem in the valvetrain
ok two things.
1. Its spelled "HYDRAULIC", not hydrolic.
2. Duramax's DONT HAVE HYDRAULIC LIFTERS.
sorry to burst your bubble...........
ok two things.
1. Its spelled "HYDRAULIC", not hydrolic.
2. Duramax's DONT HAVE HYDRAULIC LIFTERS.
sorry to burst your bubble...........
Lol.
Sorry its a solid tappet roller but that makes no sense to me as to why we never have to adjust the valves, with a solid lifter, not trying to be an ass here but can you explain that to me?ok two things.
1. Its spelled "HYDRAULIC", not hydrolic.
2. Duramax's DONT HAVE HYDRAULIC LIFTERS.
sorry to burst your bubble...........
I haven't had a chance to open it up yet. I'm hoping to get to it in the next week or 2. Oh, and according to a diesel mechanic and the Chevy dealership, they are hydraulic and NOT solid that need to be adjusted to .12", and according to Chevy they have been known to go out of whack. Either way, I guess I'll find out in a week or two. I'll post the results when I do.
there is a difference (you saying "sorry its a solid tappet roller" makes it sound like you were rolling your eyes at me as if I was splitting hairs over what kind of lifters they are)..........you said its hydraulic, and its not. Thats pretty significant.
Because the dmax lifters are huge and GM/isuzu designed them to be strong enough so they dont wear out like the aftermarket solid rollers you can get for your old muscle car.....I guess?
Thats not to say dmax valve clearance doesnt loosen up slightly over time, but its not a "regular maintenance" procedure; if you never adjust the valves in 300,000 miles, yeah they might be a couple thousandths out, but its not going to hurt anything.
If you are in there doing injectors or something (or if you ever remove the rocker arm assembly), you should check/reset the valve rocker arm clearance "just because why not".
Have you even taken apart a duramax valvetrain before or seen pictures of it? Its not anything like the powerstrokes you work on.
uhh ok well the diesel mechanic at your chevy dealership is dead wrong, im sorry.
I have a whole box full of about 50 dmax lifters sitting right here and they certainly dont look hydraulic to me.
Ditto the last two post on the solid lifters. If they were hydraulic, they would have zero lash. I feel for you guys who are getting this bs grime dealers. I don't go a week without getting a call from a customer who talked to a shop or dealer that gave them info that was at best inaccurate.
Haha, I hear ya! Big difference between a certified Dmax tech and some guy who changes brakes all day, cant just talk to anybody.
FWIW, I dont think Ive seen a diesel with hydraulic lifters. Ever.
I will admit no I have not torn down a dmax that far, done injectors on a few lbz and llys, but not an lb7, in all of my experiances I've only seen hydrolic lifters in late 80s to todays vehicals in stock form, and made an assumption, as you can see it bit me in the ass, ill admit fault on my part
It is almost pointless to argue with Ben about specifications on any year dmax. So you know. He is very knowledgeable about them.
I wasent arguing, I admited I didn't have to correct info and asked what was correct, I'm here to learn just as much as the next guy, ill admit I don't know much about the duramax as I do powerstroke, and I want to know as much as I canso I can perform more work when it becomes available
I believe 6.2/6.5's have hydraulic lifters. Powerstrokes have them too as far as I know.
I would say injector as well. Mine had the same symptoms that yours did about 2 weeks ago and a bunch of guys here on the forum recommended that I run a quart of 2 stroke oil with a tank of diesel. So far I have ran 2 quarts through with 2 tanks of fuel and my truck is quieter than ever. It is worth a try and really cheap before you start tearing into the motor. It sounds like you have an injector sticking when the motor gets warm, which is exactly what mine was doing.