Truly odd noises...

[drbenway]

Hello and thank you in advance for any help you may give me.

I have a 2007 SL hatchback with CVT and 54,000 miles on it. No big problems on it, but in the last few weeks it has developed some odd noises that weren't there for the previous 53.9k miles. I noticed yesterday that when driving in light city traffic, I have a noise somewhat reminiscent of a diesel engine. It happens about a second after I first touch the accelerator, when starting out from a standstill. It basically happens somewhere between 1,200 to 1,700 rpm and then stops. It has also happened when climbing a small hill at low speed, (under 20mph).

This morning I also noticed it happening when I first start the car. It's only about a half second in duration, but very distinct, like a cross between a bad catalytic converter and the diesel I mentioned above. It will also make that exact noise when revving the engine in park or neutral. Again it only lasts for a second.

As for the quality of the sound... It's more of a cross between a growl and a rattle. I don't believe it's a grinding noise. Anyway. It doesn't happen at speed, when you get past 2k rpm, when going down a steep hill and the rpms are higher or when accelerating to pass.

I've kept the maintenance up (oil changes/air filters), but haven't been to the dealer since the 30k (big money) service.

I appreciate any help you can give me as to what might be the cause of this, so I can prepare myself for the chance that I might have to sell one or both of my children for "scientific experiments" in order to pay for it.

[Promise Land]

have you checked that all the fluids are up to proper levels?

Is it more of a ticking? We've all experienced some form of a ticking at various mileage intervals.

[drbenway]

have you checked that all the fluids are up to proper levels?

I just had it serviced about a month ago. I will check today when I get out of work. Is there anything specific I might want to check apart from the typical oil/coolant stuff? I did have a ticking sound for a day or two around two weeks back, but it went away. It was a constant ticking it didn't get faster when you hit the accelerator. I thought it was more of the sound of something loose, than a ticking sound.

Also. When I was listening to this sound today, I noticed that it was louder inside than out. While driving through an alley with brick buildings on both sides I couldn't really hear much going on outside. But when the windows are closed, you can hear that diesel-like rattle/growl. It sounds quite loud.

Thanks for the suggestion.

[drbenway]

I checked the fluids and everything looks good. But the sound is still there. It won't make the sound if I lay into the accelerator a little more than I normally would. As long as I'm above 2k RPM it doesn't make the sound, but when it does it's quite awful.

[NissanPartsDepartment]

It sounds like you are talking about what is called an engine ping.
Are you familuar with this noise?

[drbenway]

It sounds like you are talking about what is called an engine ping.
Are you familuar with this noise?

No I am not. If that is what it might be, what would in your opinion be the cause? It is a deep, throaty sound. As I mentioned above, it sounds like I'm driving a semi. It stops at 2k when I'm accelerating. I appreciate any help you could send my way.

Thanks

[eeshazor]

I too am now interested in learning about this "engine ping." :P

[NCJack]

It sounds like you are talking about what is called an engine ping.
Are you familuar with this noise?

No I am not. If that is what it might be, what would in your opinion be the cause? It is a deep, throaty sound. As I mentioned above, it sounds like I'm driving a semi. It stops at 2k when I'm accelerating. I appreciate any help you could send my way.

Thanks

If its engine ping, using a higher octane gasoline should alleviate it. And if that solves it, I would look into having your engine cleaned since deposits can cause this. Use Pennzoil Ultra if you want it slowly and safely cleaned, or use Seafoam. Look into "water decarbonizing" on google too.

Regards,
Jack

[BBISHOPPCM]

The sound you are hearing sounds like a loose heat shield. Get under the car, and (using your fist), whack the exhaust a few times; if you hear a rattle, there you go! If the shield is loose, it can be easily re-secured.

[drbenway]

Thanks again. I'll give whacking the tail pipe a try, although it seems to have calmed down a bit since I tried better gas.

[drbenway]

First I want to thank everyone for their suggestions... I have learned that it's definitely not the heat shield, and probably isn't engine ping either. I had it into the normal shop I go for inspections and little things and they said the couldn't narrow it down any more than it's on the passenger side of the engine. And it sounds kind of like an air compressor problem. It's definitely a rattle though.

If anyone has any more ideas, they will be much appreciated. Thanks in advance.

[Moghedian]

I've got the same noise, but it is really evident to me in idle. Been to the dealer 3 times for it. They checked heat shields, tightened everything down and attributed it to me being hyper-sensitive about my car. It still does it from time to time, but I've learned to live with it.