Engine knock on CX-9 GT 2008

I'd like to report a problem:

Just bought a CX-9 GT and am experiencing a very strange rattle coming from the engine compartment when accelerating very lightly and engine being fully warm (being ran for at least 15min). The rattle is coming during 2000-2300rpm. Below and above that range, the problem does not occur. The rattling noise sounds as if some metal is grinding on one another. I think this problem I am exhibiting is by far, not normal and want to know if anyone can enlighten me.

Symptoms/Conditions:
1. Car must be hot/warm (must be driven for at least 15 minutes)
2. Must be in a drive or reverse direction. Problem does not occur in park or neutral.
3. You have to be accelerating lightly, the engine rattle occurs from 2000rpm - 2300rpm. It's not a tapping or ticking sound but rather a "buzzing" metal to metal grinding.
4. Sounds like the sound is coming from the intake or exhaust systems and the rpm is causing a natural vibration frequency that is causing a metal part to vibrate (or resonate). Could explain
5. The car doesn't seem to be power limited or anything abnormal. Drives just fine - just a rattling sound that I hate to believe is normal!

Today, Saturday, I took car to dealership. Mechanic on duty gave me appointment for Monday morning.
He said that they had a problem before regarding the bearing on timing chain tensioner.

If you drive on a quiet street, without radio on - put it in third gear manual and try to get just over 2000 rpm. Let me know if you hear something?

Update

I picked up my CX-9 GT from the dealer today. He said that heat shield around the exhaust was the problem. However, I heard the same noise but less intense. Now, the noise was very similar to the one created by the valves and lifters.
I came to a conclusion that the original noise was a combination of two. One problem was gone and now I can be certain that the remaining knock is related to the valves.

After an intense test drive, I called the Dealer and suggested to wait a few weeks to see if the problem disappears.

Has anyone had the same or similar problem and is there any suggestions?

Yeah, I had the same buzzing sound on mine also. I went to the dealer and they couldnt find where is comming from, they check and ajusted the shield exhaust but but the noise still there. Then they just create a record reporting the problem and give me a free oil change because they couldnt fix it.

GUZ! I'm so happy to inform you that I solved my problem. Dealership did not have a clue and did not do anything for me. I tried everything! Different gas grades, gas additives, changed oil 3 times, oil additives. Nothing helped...The friend of mine, who's mechanic, pointed to VVT - variable valve timing. He said that sometimes something gets stuck there in new engines and has to be worked out.
I went for a ride on highway and kept accelerating to 3000 rpm and let it drop under 1500 rpm constantly for 30 km or 20 miles. I used a manual option in the 5th gear - so it made my life easier. It solved my problem and now my CX-9 GT runs like a charm. I hope it helps you too! GOOD LUCK!!!

Zorba, thanks for the advise, but it didnt work on my for me. I still have noise.(flame) Im planning to go back to the dealer to see if they finaly have an answer to fix this problem.

OK! Let me know what is going on. Sometimes the same noise comes back. ??? Maybe is a new engine design problem.

Mazda should do something about it!

Zorba:
The rattle (or vibration) between 2000-2200rpm has been well-known (see edmunds.com on CX9). Almost all have it, but in different degree.
http://townhall-talk.edmunds.com/WebX?14@@.f19674f/0

For mine, the issue is more severe when the engine is cold. When it warms up, the vibration fades a little, but it is still there.
I suspect that it has something to do with the natural frequency of the front end structure which resonates at the same vibration frequency with that of engine when revving at 2000-2200 rpm. Mazda needs to come up with a kit of some sort to reiforce the front end structure to get rid of the vibration (or resonance).

Anyway, just my guess. On mine, it shows, but it does not annoy me.
On edmunds.com, one guy reported that his dealer mechanic tightened some screws under the hood, and the vebration was significantly improved. You might want to check it out there.

(drinks)Ceric,
Thanks for your post I fix my problem. I print out your link about edmunds.com and I toke to the dealer as a prove that Im not the only one. They keep the vehicle the all day giving me a Mazda 3 as a loanner, and when I pick it up in the afternoon all vidration and rattle was gone...(drinks)

GUZ said:

(drinks)Ceric,
Thanks for your post I fix my problem. I print out your link about edmunds.com and I toke to the dealer as a prove that Im not the only one. They keep the vehicle the all day giving me a Mazda 3 as a loanner, and when I pick it up in the afternoon all vidration and rattle was gone...(drinks)

Click to expand...

Please post the operations performed and parts utilized. The information is right on your invoice. Thanks in advance.

My CX 9 AWD GT does this rattle too...

I was having a CX 7 previous and never heard anything like it before. Now, it is very stressfull and I hate Mazda engineers for this. Mazda dealership told me that it is normal for a new car to sound like this , until it is breaking in....
This is a very very stupid thing to say...i suppose. The only thing that CX 7 was breaking in was that RPMs were decreasing slower when was new and until 8 k miles was a truly sports car.
By the way, does anyone knows why mine is making only the rattling sound when I'm idling the engine at stops and traffic lights with the shifter in drive ?
I have to mention that my RPMs are around 600-700 RPMs and when I drive I do not hear a sound during the movements. Only when it's standing still....
I really dislike the noise shielding because when I'm throttling the engine sounds too noisy , compared to CX 7.
I guess Mazda CX 9 isn't a very "polished" car compared to the CX 7....
If anyone experienced the same rattle during standing at traffic lights and stops....please let me know that I am not the only one...with this problem...
Thanks !

Zorba: I'm glad you started this thread / reported your engine knock as I have started to experience engine knock in my 2008 CX-9 GT as of about February.

As for the noise, it definitely sounds like classic engine knock and occurs every time the throttle is applied when the engine is under load. The knock routinely occurs in two circumstances:

1. Going up a steep hill
2. Trying to accelerate when the automatic transmission has it in too low of a gear.

It also seems to be a little more evident/obvious when the vehicle is cold; however, once the vehicle warms up, the engine knock does still occur. It does NOT occur when driving on level terrain, regardless if the engine is cold or warm (or at least it is not loud enough to hear inside the cabin when driving). Of course when driving on level terrain, the engine is not under much of a load either.

We have taken it into the dealership twice. On the first trip, they said it was the brake booster connect rattling. While this made absolutely no sense to me, I let them have their chance to repair the problem. As you may expect, this did not fix the engine knock. On the second trip, I decided to be more proactive, and printed out the TSB pertaining to loss of power. I had hoped the reprogramming of the codes would help the engine, and if I were lucky, would eliminate the engine knock. Unfortunately, this did not fix the problem either.

Naturally, in the owner's manual it recommends 87 octane.

I plan to take the vehicle back to the dealership a 3rd time. I can offer the first time I took it to the dealership they did offer the passing comment that another CX-9 had been taken in to be serviced reporting the same problem. Perhaps this problem is on a larger scale than just this thread. Perhaps it only applies for a certain period of vehicles coming off the line. I will keep everyone updated on my developments. Please do the same.

As for any other details on my end, it is 2008 GT purchased in June of 2008. We've had the vehicle about 9 months before we started to notice the engine knock (or at least for the engine knock to be loud enough to make itself evident). The vehicle currently has about 9,000 miles on it. Outside of this problem (which unfortunately is no little problem), our CX-9 has been a great car for our family. We are hopeful a fix can be found.

Unfortunately, I am experience it at standing still revs...

gte331r said:

I'm glad you reported this as I have started to experience engine knock in my 2008 CX-9 GT as of about February.

As for the noise, it definitely sounds like engine knock and occurs every time the throttle is applied when the engine is under load. The knock routinely occurs in two circumstances:

1. Going up a steep hill
2. Trying to accelerate when the automatic transmission has it in too low of a gear.

It also seems to be more evident when the vehicle is cold. Once the vehicle warms up, it is more subtle in the above two instances. It also does NOT occur when driving on level terrain, regardless if the engine is cold or warm (or at least it is not loud enough to hear inside the cabin when driving).

We have taken it into the dealership twice. On the first trip, they said it was the brake booster connect rattling. While this made absolutely no sense to me, I let them have their chance to repair the problem. As you may expect, this did not fix the engine knock. On the second trip, I decided to be more proactive, and printed out the TSB pertaining to loss of power. I had hoped the reprogramming of the codes would help the engine avoid being under load, and if I were lucky, would eliminate the engine knock. Unfortunately, this did not fix the problem either.

Naturally, in the owner's manual it recommends 87 octane.

I plan to take the vehicle back to the dealership a 3rd time. I can offer the first time I took it to the dealership they did offer the passing comment that another CX-9 had been taken in to be serviced reporting the same problem. Perhaps this problem is on a larger scale than just this thread. Perhaps it only applies for a certain period of vehicles coming off the line. I will keep everyone updated on my developments. Please do the same.

As for any other details on my end, it is 2008 GT purchased in June of 2008. We've had the vehicle about 9 months before we started to notice the engine knock (or at least for the engine knock to be loud enough to make itself evident). The vehicle currently has about 9,000 miles on it.

Click to expand...

Your Mazda seems to have a slightly different issue than mine...but I guess that a test on a drive line won't solve the problem. And I think we paid also too much for a car with too many issues...

Ahhh, by the way. They ( the dealership) have sold me the car with a loose connector on the right side mirror...so wasn't powered at all and also the BSM wasn't working... The next day i went to the dealership, storm into the GM office and told him that the car wasn't merely checked when they've sold it. So, once again , painless experieces on a Mazda dealership are not common...i think...
And I really don't know what in the name of God i supposed to do with the 47 k car that has all the options but no noise reduction also...?
I really wonder if I am a suc..er or not ?

A guy over at edmunds.com just reported that the knocking noise problem of his CX9 was fixed. The cause was failed VVT (variable vlave timing) actuator.
Just to raise another possible causes for your engine noise issue. If so, the noise level should increase proportionally with engine RPM.

That is me - same username over there. I had the same symptoms as Zorba. They had to crack the engine open and replace the VVT lift actuator. The noise is gone now. It was just over $2K charged to Mazda. If you have those symptoms, get it in. The place that fixed mine was Kings Mazda in Mason, OH. They had it for 10 days, but gave me a loaner CX-9 to use for free. They did tell me I was not the first with that problem.

John

So glad to see all those responses and concerns. The update from my side would be that engine noise from my mazda cx9 gt is gone - by itself.

Since noise is gone I feel more power coming from the engine. Car runs like a charm and hoping to stay this way.

Maybe, somebody should open a new thread regarding the recommended oil grade: 5-20. Summer is coming and I'm concern that this oil is too thin and might damage the engine.

The factory recommended oil isn't going to damage the engine. That's all I've put in.

I am running 5w-30 synthetic. the 5w-20 is the manf's way of getting more MPGs. Personally, I feel abit more secure running a 30w oil. When winter hits, I will go with a 0w-30. Just my 2 cents.

I will start a new thread regarding the oil issue - so others can find help easier on that topic

Our home temps run from 5f to 105f. Plus we regularly drive to Phoenix and other 115+ locations. Never had one problem with the factory recommended oil.

They recommend a specific weight for a reason, and they know a lot more about why a certain oil should be used than you guys.

You're more likely to cause a problem by second guessing the manufacturer, without knowing exactly what the different weights actually mean.