Ok, i'm a little freaked out about my car right now. Yesterday I went to start up my car and it made a horrendous racket from the engine. Loud metallic tapping, sounded really bad to me. Immediately turned it off, checked oil levels (fine), started it back up probably 4 more times last night with the same sound. Had it towed to Nissan this morning and they ran it for a few minutes and the sound went away.

With all of the stories about engine failure, i'm worried. Should I quit worrying and keep driving it, or look into trading it in while it's still running ok?

Matt

 

what did Nissan say after they let it run/tested it?

 

The "master tech" said that it might have been due to carbon buildup and he recommended the fuel system treatment.

I had it parked on a slope all of yesterday, I don't know if that has anything to do with it. I drove it around this evening after picking it up and it is running exactly the same as it did 2 days ago, no engine tapping or knocking. I'm still worried though - the sound was sooo loud and sounded sooo bad.

 

Same thing happened to me two days ago. Very loud knocking noise, and it was gone after 2-3 minutes. It came from top of the engine, I guess valvetrain, but I could not find any info or tsb. It works perfectly smooth now.
I am puzzled too.

 

bad gas?

 

No idea. It's ran perfectly fine for the last 2 days, i didn't change a thing. Guess i'll just keep my fingers crossed.

 

mine did the same thing but i think it did it because it was on a slope never heard it again

 

May have just been valvetrain noise. Hard to tell though without hearing it firsthand. I would just keep listening to see if it comes back.

I've just recently noticed what sounds like valvetrain chatter when accelerating at low RPM's. After doing some reading it seems to be somewhat common on these cars. I also read several instances of loud rattles during start-up, but mine hasn't ever done that. My Explorer used to chatter like crazy for a few seconds after start-up though.

 

It's been fine ever since that one occurance. I'll keep my fingers crossed but hopefully it was just something to do with being parked on the slope for the entire day.

Matt

 

Mine has made a sound like this a few times. I don't know the cause, but have narrowed down the circumstances...it only occurs on start-up when the previous run cycle was very short. Example: on a particular day, the car is only started for about 15 seconds to move it from the driveway to the garage; the following day the noise occurs upon start-up. It has never occured when the previous run cycle was long (up to normal operating temp). It's almost like the short run cycle is causing the following start to be somewhat of a dry start, but I'm just speculating.

 

the timing chain tensioners are hydraulically pressurized. That is, the use the engine oil pressure for their strength. Occasionally a situation will happen where they lose pressure and the chain becomes loose. This is my theory at least...

 

Any more info on this? I got this noise for the second time today... sounds like car had no oil in it but it went away a few minutes later. Oil is full.

Both times this happened to me, the car had been sitting for at least two days without being started. I normally drive "somewhere" every single day, and now I'm scared not to...

 

2-3 days of sitting will make the car run a bit dry for initial starting for just a few seconds.

If you are hearing this noise for more than 10 seconds (of initial startup) take it to a shop (the dealer or someone highly trusted) and have them take a look into the problem. If it is under 10 seconds this is normal.

 

Exactly what vqeric said has happened to me in this car as well as two previous maximas. Short cold start and stop, then later when restarted sounded like engine was coming apart.