2011 Chevy Traverse LS 3.6 V6 44000
miles. Out of the blue I heard a light
constant ticking noise while driving. Next
day I started the car to warm it up before I
put my kids in and could still hear a light
tick. As soon as I started driving the tick
turned into a full blown knock. I turned
around and brought it back home. No
trouble codes have come up. I brought it to
one mechanic who immediately said "rod
knock, get rid of it" just by sound alone.
Second mechanic thought maybe rod
knock and wanted to drop the oil pan to
verify. Well to get to the oil pan on this car,
you have to pull the transmission and a
bunch of other stuff. So basically he would
have to pull the whole front end off from
the bottom to even diagnose the issue. We
are out of all warranties, and even
diagnosing would be extremely expensive.
Basically he wanted us to have a
replacement engine ready to go because
of the labor involved to even find the issue.
We decided to sit on it for now. I've been
searching around and I have found that
there's a slight possibility that our noise
could be coming from the intake manifold.
Maybe the flappers are loose or broken
and are banging around in there. I'm pretty
handy, so I'd like to try a couple things
before I junk this car that I still owe on. My
question: Is there a way to disable the
intake manifold while on the engine to see
if it changes the noise? It seems pretty
straightforward removing it and even
swapping it with a new one, but I'd like to
be able to actually diagnose the issue first.
I am also planning on pulling the power to
each cylinder to see if the noise changes
as well. Also, like I said, no engine lights
are on, and the car drives fine. No loss of
power, as far as I can tell no oil pressure
drop, etc. it just sounds like it's going to
Kill the power to cylinders one by one and if the knock gets noticeably quieter a rod bearing is the likely cause. My guess is you mechanic is correct. Has anyone bothered to check the oil level in the engine?
Yes, I plan on doing that as well. I didn't mention that oil level is fine, I always change my oil and filter when I should. As a matter of fact, I got an oil change maybe 300 miles prior to the knock. When the mechanic pulled out the oil he did not see and obvious metal shavings or anything. I'm going to check the oil filter myself as well.
A spun rod bearing may not put lots of metal into the oil.
Thanks, good to know. I think my chances of spinning a rod bearing are on the low end, since I have so little miles on the car, I've never beat on it, have always kept up on maintence, never let get low on oil. Could it be a spun rod? Sure. Could it be something else? Maybe. I just want to find out for sure myself. I can't drop the oil pan, or tear apart the engine myself, so I'm looking for other ways to diagnose. All I want to know is if there's a way to stop the intake manifold from opening and closing the flappers while the car is on to see if I can get a change in the sound. I found a gm service manual somewhere online for my car that said when someone brings in this car with a rod knock sound to first replace intake manifold, if that doesn't work, proceed to tearing apart engine.
Bob gave you a good suggestion, pull a plug wire one-by-one, and see if knock changes. It will not only let you know if it is indeed rod knock it will let you which cylinder is the guilty culprit. I would also look for an exhaust leak, pull valve covers and listen to valve train - you can also determine if it is lower end related or valve train related by determining if knock is equal to engine RPM (lower end related) or one-half engine RPM (camshaft/valve train). BTW there are a lot of complaints about the high-pressure fuel pump being a source for a ticking noise, and that is driven by the cam, so again if the tick is at half engine RPM, that might be a source for your noise. This engine being direct fuel injection, I think you would be better off taking it to a GM tech and not a neighborhood mechanic, they might be more familiar with the noises common with this engine.
Thank you for the insight! I'll be digging in this weekend. Hoping I get some answers before I decide to just drive it off a cliff
Please post what you find during your investigation of the knock.
Will do. Found an interesting tidbit that I'm going to look into as well: the DI systems can cause major carbon buildup in the back of the valve stems since there's no fuel to wash over them and keep them clean. I pulled off my air filter yesterday because I had a minute to take a peak. My pcv port was pretty full of oil and the air intake tube was pretty saturated too. The throttle body was also coated with oil. Known issue from what I've read. I'm thinking about getting a bottle of sea foam and spraying it in the throttle body to try to clean up the valve stems. I only drive the car for short trips so maybe carbon buildup is a possibility.
It's a rod. Thanks for the help guys. So if anyone wants to buy a 2011 Chevy Traverse that's going to need a new engine, but otherwise is in great shape.... I have one available. I don't have the cash to put in a new engine at the moment, but someone could make a good profit if they have the time, money and space.
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