# New Member looking for Guidance



## Marc (NJ) (Dec 13, 2015)

Looking to buy my son a 2002-2006 Altima for his first car. Most likely a 4cyl. Looking for recommendations of what to look out for when buying one. Any year better than the other? etc. Thanks in advance.


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## rogoman (Dec 16, 2004)

Be especially careful with the 2002-2006 models that use the 4 cyl QR25DE engine. The common problem with those engines is the catalytic converter breaks down and bits of catalyst substrate get sucked back into the combustion chamber and score the cylinder walls. The QR25DE uses the variable valve timing for EGR rather than a conventional EGR valve. It opens the exhaust valve slightly during the intake stroke to accomplish this. The catalytic converter, which is part of the exhaust manifold, is so close to the head that the bits of debris get sucked in past the exhaust valve with the exhaust gases. Nissan claimed the reason for this was the ECM programming. A recall for 02-06 QR25DE equipped Sentras and Altimas was initiated years ago to correct this problem. An updated ECM was provided, updated manifold heat shields and several other things and in some cases, replacement of the exhaust manifold assy. and engine short block. If the vehicle has already had the campaign performed and you're planning to buy one, then you should be OK.


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## Marc (NJ) (Dec 13, 2015)

Thanks for the insight rogoman, I will definitely use it when shopping for one.


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## Marc (NJ) (Dec 13, 2015)

How about the V6 3.5, how are they?


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## rogoman (Dec 16, 2004)

The VQ35DE V6 used in the altima's, from many reports saying that it's a very reliable engine. The one drawback that I consider to be a PITA is the replacing of spark plugs. To replace the plugs on the right bank, (closest to the firewall), the intake manifold, throttle body and it's coolant connections, and the MAF need to be removed. If you're planning on purchasing a V6 model, negotiate with the dealer as part of the purchase to have them replace the plugs. The replacement interval for the plugs is 105,000 MI, so you'll be good with the plugs for quite a long time. Be sure to use the NGK OEM platinum tipped spark plugs.


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## Marc (NJ) (Dec 13, 2015)

What insight can you give on the earlier generation 98-01?


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