Girlfriends Maxima sometimes makes a rattle under the hood?

[Sid]

I'm not sure what it is but it freaked me out yesterday. We were driving and from a stop once she hits past 2000 RPM's you can hear this rattle from under the hood. It's not a ping because I've heard that before. BUT I've never heard a knock honestly. It doesn't sound like a marble in a can or anything. Just like a quick rattle of some sort near her intake manifold. I kind of freaked because I thought maybe for some reason it might be the Pureone Oil filter or the Castrol Syntec 5w30 (Felt bad because I made her switch to synthetic for 6 months to see how she likes it.) Checked oil. Gorgeous! Crystal clear and filled. I think I've ruled out the filter because the car sounds completely smooth when she first starts it up. I figured if it was the oil filter it would definitely give indication at start up.

What do you think? She needs a new air filter which is being installed today. Maybe a PCV valve. The car runs very smooth. Gets bad mileage though. She's run out of warranty. Any help is appreciated.

 

[topz]

Could it be timing chain tensioner? Mileage/year of car?

 

[ebaker]

Could be the variable valve timing gear (VTC), especially if it's a 92-94 DOHC motor.

 

[Tosh]

A quick rattle? Like detonation that suddenly stops? Maybe the knock sensor heard it and retarded the timing? Are you sure it's not a ping?

 

[methusaleh]

Could it be as simple as a hood prop rod not put back in its place securely? That happened on my girlfriend's Stratus all the time...

 

[andyd]

loose heat shield?

 

[Sid]

The car is a 2003 Nissan Maxima W/3.5L engine. 28,000 miles. Given oil changes earlier than it should. Just changed the Air filter to a Pureone Air Filter today.

It still seems to do it at about 2K RPM's. But not as bad as a couple of days ago. She says she hears it sometimes but she thought it was normal. I couldn't get her to tell me whether she heard it before or after the oil change. I'm just wondering if parts aren't getting lubricated properly. Then again the sound is near the intake manifold. I wish I can explain the sound to you guys. It's like a really loud hard drive under the hood. Imagine your hard drive seeking for information and amplify that sound. Sort of like that. Weird I know. My old 90 Mercury Sable with the 3.0L engine did it ALL the time. Ran for years. She puts 93 octane. I'm not sure if the car calls for it but I keep telling her not to use higher octane if it calls for 87 because it's useless if the car not designed to burn 93.

 

[tdpark]

I think the Maxima is speced for High test.

 

[Tosh]

Time to get out the home-made stethoscope!

 

[kcryan]

its got a knock sensor though

 

[unDummy]

If its spec'd for high test, use it.
A knock sensor still needs to sense knock which is easily available on lower octane fuels in 'hot' motors.
Stick with the 93 if that is what the owners manual recommends for best performance.

Dump the oil filter. Its an easy test to see if your motor doesn't like Pureone or if you got a defective one.

At 30k miles, flush the coolant and change the thermostat.

Check with the online Maxima forums to make sure that nooone else had issues like that. I know that some other Nissans had loose nuts, bolts, or screws. The engine will run even worse after eating a screw.

Change the fuel filter(if it has one), and use a quality FI cleaner in the next few tanks of gas.

 

[Sid]

quote:

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Check with the online Maxima forums to make sure that nooone else had issues like that. I know that some other Nissans had loose nuts, bolts, or screws. The engine will run even worse after eating a screw.

Change the fuel filter(if it has one), and use a quality FI cleaner in the next few tanks of gas.

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I'm a newb over at the maxima forums so I have to 15 posts to make a new topic.

I'm sure the engine didn't eat a screw. Her piston could say bye bye at that point....in fact could a screw even fit past an intake valve?

I did put in a bottle of Valvoline Fuel System Cleaner.

I was talking to a friend and he says it's some sort of sensor. Couldn't remember the name of it. Said a few of his cars have done it. I'm not sure honestly but I will post it up on the Maxima Forums to see if I get a response. Thanks!

quote:

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If its spec'd for high test, use it.

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What is Spec'd for high test?

 

[Blue_Goose]

My 2005 Matrix had the same sort of rattle that you are describing..granted much different engines but at 3k on the tach or around 40 mph I would get this rattle for a second.

I had Castrol GC in there but it also made the noise when I had Pennz Plat and M1 in there...however it did not make the rattle with the first fill of M1(prior to the Pennz Plat)

Underlying theme is they are all synth...

My last OIC I put in Chevron 5W30 SL and lo and behold the rattle is gone

The only thing I can think of is whatever it was did not care for synth oil...I dunno...maybe just a weird timing coincidence with the OIC perhaps

I'll be doing a OIC this weekend and I may put Pennz Plat back in...it will be interesting to see if rattle returns


Goose

 

[CBR.worm]

3 things come to mind. 1st, the max requires premium. It will lightly ping on 93 under some conditions.

2nd. My wifes maxima makes a strange clicking noise, it seems to be like 5 clicks in a row as the engine drops down near idle speed, and sometimes at a slow (20 mph) cruise through the neighborhood. In her car we tracked it down to some kind of valve in the plastic intake manifold that was opening and closing. Someone said it was the dual length intake runner butterflies opening and closing - basically resetting the zero position. Hers is an '00, so it is a 3.0 instead of 3.5, but I imagine most of the stuff is the same.

3rd. I think the butterfly screw would pass pretty quickly through the engine unless it lodged itself either in the top of a piston, or in a valve seat. either one would cause a change in operating noise that would be pretty pronounced. I think the more common failure mode is that the screw gouges the cylinder wall before leaving the cylinder and causes high oil consumption. I don't know if this was an issue on maxima's - I only heard about it in altima's.

 

[Sid]

Well I just heard one person on the maxima forums say he had to replace his engine because of a butterfly valve screw. He said at first he just had the sound I had. Then the tech was revving the engine and the screw went from his intake manifold into the combustion chamber. Not a good move. I'm taking it hopefully this Thursday to the deaoler to see what they say. I have the feeling this won't be easy.

 

[Tosh]

Oh dear! At least it's still under warranty, right? Let us know what happened.

 

[Korean_redneck]

Is the hood stand placed in the hoood stand holder?