I need your help! I have a 2001 Maxima with 30K miles. Lately, I've noticed the engine sounds rough when started for the first time in the morning. It happens under light to medium acceleration but when pushed very lightly or very hard the engine sounds ok. Is this "valve clatter"? Sounds a bit like a sawing machine!!!

Now it started happening even after the engine has warmed up. For example - after a long commute on the highway, and when I hit city traffic. But it is pretty cold out. Is this normal? Shall I bring it to the dealer? Any help will be appreciated!

 

The engine shouldn't sound differently when its cold outside. I'd like to know your definition of "pretty cold". Are you sure the sound you hear at start is the same you hear during normal driving? Is the sound at start a high pitched whine? If so its just normal starter whine which is pretty normal for the Maxima in cold weather. Is it a metallic rattle? Probably the timing chain which is also somewhat normal (bad sound but not doing any damage).

Is the sound during normal driving a slight rattle under load? If so, it could be the coil packs have packed it in. Search the TSB stickies for "coil pack" which will give you all the info you need.

 

Thanks for replying. Yes - It sounds like a slight rattle under load. And it only happens when engine is under moderate load at low RPM. (I have an auto - so I can't really put it under much load without downshifting).

But if I gun the car or apply the gas very gently - the engine sounds fine.

This started happening only when the engine was cold. Now I get this every once in a while (but not always). Oh, I'm in the NE - around 5 degrees F in the morning.

I looked at the posts here about the coil problem but I'm not sure if indeed it is the coils. I get as much power out of the engine as before. And the noise goes away at high RPMs (say above 3K).

 

Can anyone help?

I brought the car to the dealer, but they couldn't duplicate my engine noise/rattle. I mentioned the coils TSB, and even though my VIN is within the range of affected engines, they couln't change the coils before hearing the noise.

I'll have to leave the car overnight with them. First thing in the morning when the engine is really cold I get the knock under moderate acceleration. Sound like a sawing machine.

Can anyone suggest what it might be? The dealer said if it were the coils the engine will knock when warm, not cold. Mine knocks always when very cold, and occasionally when warmed up!

Oh well...

 

Mine has done this maybe five times. But only when I first start it up. After about 20 secs it gradually goes away. It's never done it when it's warm. It really only does it when the following sequence of events take place: I have to move my car out of the garage (the car runs about 30 seconds). I turn it off and then the next morning or the next time I crank it it sounds like the timing chain or valves are sticking. I just coughed it up as lack of oil at the top of the engine.

It is a bit disturbing, but your not alone.

 

What kind of gas are you using?

 

Yes--sounds like pinging if it is under a load.

 

I use 89 octane. But it's not an octane problem. It's different from pinging valves. When mine does it, the engine is rough idling and just sounds like metal grinding. I can't imagine the timing chain chain getting kinked, but that's what it sounds like.

 

Mine has been doing it for a long time and just like sgrd the dealer's couldn't determine what was wrong with it if anything. They told me that they would have to call in a tech to tear the engine apart and find out what is wrong with it.

They drove it and said it runs fine and they couldn't hear anything then I drove them around in it and pointed it out to them, that's when they said bring it in and the tech would tear it apart.

I'm not taking it in to have some tech tear my engine down, it seems to run fine despite the noise and I haven't had any engine problems at all. My car has over 114K on it and other than a new tranny I've had no other problems thank the Lord.