I've been searching through threads for an anwer to my startup rattle and found some answers, but nothing concrete. My VQ has had no problems with rattling until about 100k. It started with the bb's in a can rattle on cold startup- ratcheting sound that could be the cam tensioner. Its on the list of fixes as is really hasn't been all that bad. Some starts it doesn't even make the ratchething metallic sound for the first few seconds. I had to run out of town and the G had sat for 4 days. I came back to start and it made the ratcheting sound which went away , BUTTT also a loud tapping /ticking sound that lasted about 10 minutes or until the car warmed up. (i'm talking loud-thought i blew the engine) My mobil 1 has about 700 miles on it and oil levels are full. I wasn't beating on the car or anything before i left. It almost sounded like the valvetrain wasn't getting oil or somthing? It was definatly a topside engine knock, not like a lower rod bearning. Once car was warm, i took it for a drive, and no problems and sound was totally gone. Any thoughts on this? engine has 110k synthetic every 3k since new. its and 2004 non revup. Only engine related mods are Berk Cats and Z-tube with pop charger. Again i was searching and found rattling noise threads, but nothing exactly like the noises i heard. It sounded like straight up metal on metal till the car was warm....and now it doesn't make the noise anymore. I wish i woulda had it on video.

 

How long is it sitting for between startups? You could try a thicker oil.

 

Sounds like you've taken very good care of your G for all those miles changing oil frequently with synthetic. Can we assume you checked the oil level after she was making all those crazy noises? With 100K on her clock and leaving it sit the noises you heard could be alternator bearing/water pump....anything. As long as those same noises don't occur frequently I wouldn't be concerned. Don't take her to Infiniti if they do....
Gary

 

@G35DREAM - ive been running 10w30 mobil 1 synth high mileage with no problems for the past 5 changes. Actually it stopped my typical VQ valve cover leak lol. (well just bought me time i'm sure till i have to replace it. Not sure if i should go any thicker. My G does not burn any oil at all. Every 3k the level is almost exactly full.

@Gary C - thats exactly whats pissin me off, is that i am ocd and meticulous about all my cars and bikes. I don't beat on my G at all, thats what i have my bikes for. Its a 5at, my grocery getter lol. The sound definatly sounded like it was right under the valve covers or very close proximity to it. I have started to get the slight ratcheting sound that other forum members have stated could be the cam tensioner. I saw lots of posts about that. But this was different. This is the first time it sat for 4 days, but i don't think thats out of the norm for any car. Especially one thats in the garage and taken care of. I thought maybe alternator or A/C or water pump too, but this def sounded top side of the motor. Maybe Cam gears or somthing. Almost sounded like the lifters were outa lash. Just trying to avoid the Stealership as much as possible. I can do most work on cars, but when it comes to ripping engine internals apart i usually take it to the stealership, and i haven't found anyone reputable that works on G's here in PA yet.

Thanks for your responses though, even with the G issues i wouldn't trade her for the world....unless the world was a new 370.....lol

 

started her up tonight.....banging.....missing....rattling....rou gh idleing......looks like its off to the stealership....def didnt sound good....

 

Well good luck man.

 

thanks, will post up with what they find. After talkin to a tech on the phone he's guessing tensioner or problem with lifters not getting oil to pump up....don't know how sludge could remotely be a problem with my oil change choices and intervals....

 

any updates? mine does the same random start up noise you mention..It does it some times, ofcourse the dealer can not find the problem when I take it in..

 

@Vp-G - had it to a friends garage that specializes in nissan. Final verdict is the tensioners are starting to go, but my problem was lifter related, not the actual tensioners making noise. Did an entire engine flush with Castle* motor flush. (pour into oil, let it idle for 15 mins, then drain all old oil out) Replaced it with a New Purolator Pure One Filter and also German Castrol 0-30. Honestly, i have no valve chatter at all anymore, it was almost like a lifter wasn't pumping up or oil wasnt getting up fast enough. Whether it was the drain back valve on the filter, the flush or the 0-30 castrol, i'm not 100% sure, but it makes no valve noise whatsoever on startup. Let it sit for 2 weeks and started, with still no chatter! Makes slight tensioner rattle on started which sound almost like a ratcheting sound. Not a rhythmic banging or clicking, just a quick ratchet sound once and awhile on startup. Hope that helps! I will update if i find anything else. The tech said the VQ engines tolerances are tight and he has seem them respond in cold climates to the better cold flow of a 0 weight on startup. Just his .02cents

 

yes I do have that ratcheting sound you speak of once in awhile. It is more noticeable now that it is getting cold. just don't know what it is

 

if its the ratcheting sound, more than likely it is your cam chain tensioners that are starting to go. Theres slack in the chain until the engine is running. From what the tech was telling me they just wear down. The more high RPM the engine sees the sooner it will wear (like everything else) Search the forum as there are a few writeups on this problem. Some guys say they've run 50k+ with this problem, and it has not gotten worse or worn anything else out. I'm going to replace mine when i do a water pump and alternator in the spring. Just to knock out all the front engine stuff. The problem i had other than ratcheting was valve related. It was an upper engine banging on startup for the first 45 seconds everytime i started it. And oil was totally full. And i'm talking banging, not ratcheting. Rhythmic loud loud ticking. Again after what i did with the flush and oil, i only have the slight ratcheting that was there before this valve problem. You are right though, in the cold the ratcheting seems more pronounced. Not sure if its the cold metal and plastics resonating or whatever.....

 

thanx for this thread im having the same kind of noises and wasnt sure what it was either

 

yeah it seems alot of the VQ's have this issue....its just hit or miss.....revup and non revup..........I also searched over on the Z forums and found the same info. I did find a couple of guys on the Z forum that added Forced Induction to their VQ, while this ratcheting was happening, and still never had any reliability issues. Like anything, i'm not gonna bang it off the rev limiter to see if the startup noises get worse or not....LOL........but gathering all the information, it seems the ratcheting will not cause performance or reliablitity issue in normal driving and useage. BUT it is somthing that if you have the extra cash around and are doing somthing to the front of the motor anyway, it should get fixed. Most seem to start ratcheting around 60k, give or take. Mine started at 90k miles. 105K on it now no problems and it hasn't gotten better or worse. Doesn't miss or sputter idle rough, or anything. Just did new plugs at 100k.