On the 3.5s like yours, MOST likely it has a broken timing chain guide!
Yes, I have the TSB and I'm aware of the issue ... the chain tensioner guide slider for the two secondary cam-chains wears out very quickly, and the cam-chain starts chewing on the metal plunger and backbone of the tensioner. See this thread for some photos, page 1 and 3.
wierd engine whine noise - Maxima Forums
My question is - are the Altimas just as susceptible? It's very strange, because on the Altima boards there is hardly any talk about it. Yet, on the Maxima and Frontier boards there is all kinds of talk about it.
I talked to a couple Nissan dealer service departments, and they've never even heard about this problem. I think it takes about 60K miles for this to show up, so maybe there will lots of owner's who suddenly have this issue, and will notice it by the whining made by the cam-chain when it finally eats down to the metal on the tensioner. This issue seems to be a pretty hot topic on the internet too if you search for "NTB07-042".
I want to know what the hell Nissan was thinking. They have had cam-chain tensioner problems since the first generation Altimas (1993) and they yet haven't figured out a good design? I did notice the technical bulletin does NOT include 2002 and 2003 3.5L VQ V6s for some reason. I'm thinking they must have tired to save 5 cents per tensioner and switch to some junk plastic starting in 2004.
I just bought a used 2004 Altima 3.5 SE with only 18,500 miles on it and figured it was going to be trouble free after talking to the dealers and they claimed that motor was "bullet proof". Unfortunately, the power train warranty on the car was over Oct 2008.
I think Nissan is going to in for a rude awakening when all these VQ engines start whining in the next year or so. I'm assuming they all will eventual eat down the tensioner slide block ... unless there is something I don't know, like was it only a few bad batches of tensioner that made it into production? Anyone know? Since there is no VIN beak in the technical bulletin, I'm thinking every one listed in the bulletin is a ticking time bomb ... including mine.
I'm going to write Nissan about this ... there should be no excuse for such shoddy engineering. They should have their cam-chain system perfected by now on all their vehicles.