White Smoke Billowing From Exhaust After Repairs

Well, I haven’t had a chance to sit down with anyone at the Credit Union to discuss finances regarding vehicle trade ins since this whole situation occurred. I’ve been too busy working. I inquired about refinancing the vehicle about a week before I took it to the shop, initially.

The problems with 2002 Altimas (and I am talking about 2.5L i4, and I am not sure that it applies to the V6, but it is possible that it can) are NOT bad engines. Failed engine is a result of a failure of pre-catalytic converters. Here what happens.

There are two converters in the car, one is the a combination of exhaust manifold and a catalytic converter, which is bolted the cylinder head in the front of the engine (2.5L i4, V6 may be different). The catalytic converter is filled with the honeycomb structure which suppose to burn off remaining hydrocarbons. It is a component of the emissions system. The problem with this particular design is that honeycomb material in these converters have tendency to crack, and break apart. Another component of the emissions control system in the modern cars is Exhaust Gas Recirculation (EGR) system, where portion of exhaust gases is diverted back into intake manifold and recycled in the engine. In Altimas (and possibly other Nissan vehicles with two catalytic converters) pieces of honeycomb lattice from the pre converter are sucked into intake manifold through EGR valve/passages, and end up being sucked inside cylinders. When this happens these pieces will rattle inside cylinders until they either burned by exploding gases, or blown out the exhaust valve, but while they are inside the cylinder they scratch/score the cylinder walls, which causes damage to the rings, which causes decreased compression, and at that point engine usually begins consuming oil.

Tester

I’m confused. Earlier you said you were getting a “rebuilt” engine. That sounds like a used one unless it had 66,000 when it was rebuilt. Either way, I’d recommend just driving the Nissan until you’re in a much better financial position.

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