#1
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2005 Altima 3.5SE p0420 code, and now white smoke out of passenger side exhaust
Hi everyone, I was driving my car (83K miles) home during a snow storm and just before getting home I heard a clunk (Thinking I
had probably hit some high pile of snow on the unplowed road) and didn't think much of it until 5 minutes later I got the SES light but didn't notice any change in the running or idle of the engine. The next day I didn't run the car until I had to move it around my driveway to make space for guests and then came the smell of gasoline (Not rotten eggs) and white smoke from the passenger side of the dual exhaust. So at first I was thinking I might have knocked a seal loose, but now I'm worried it's something much much worse that coincidentally happened after the thunk. The code I got from my reader: P0420 - Catalyst System Efficiency Below Threshold (Bank 1) Here's some recent background of issues that may or may not have affected this situation.
Any help or advice on this would be greatly appreciated, thanks! Last edited by londonfog; 02-03-2013 at 05:29 PM. |
#2
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So I've done a little more research and so far I've found that it might be either a head gasket leak or that my valve stem seals have perished.
My head gasket is only a few months old, and I could swear the smoke was white coming from the car, but the smell of fresh oil/fuel being burnt rather than rotten eggs is also pushing me toward the valve stem seal. People have been saying that if it's the valve stem seals, though, that the smoke should be blue. |
#3
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1. white smoke at start up in a cold winter morning and disappear as the engine warms up could be just condensation. if the issue persists, coupled with loss of coolant with no visible external leaks, then coolant has somehow find its way to the combustion chamber. could also be cracked engine (block//head). since you heard a big "thump" while driving, its not a bad idea to go underneath to do a visual of exhaust piping and EVAP components.
2. blue smoke, you got it, oil burning. you just had an oil change, so check oil level be sure you didn't overfill. 3. head gasket failure. you said its 5 months old. there are many factors that can cause HG to ffail, such as: damage to the mating surfaces (engine block and head), warped mating surfaces (and not machined) due to lack of complete engine cool down before disassembly, improper tightening (torque) of head bolts, and damaged head gasket. Suggestion: send for Oil Analysis to confirm coolant and oil have mixed. |
#4
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So the smoke was just condensation when I went to check it out again, I was just paranoid the first time I saw it as it's been colder with the recent snow storms that passed through.
I had the dealer diagnose it and the rear catalytic converter has failed so it looks like I'll have to swap it out. So far the dealer has quoted it at $1100, and Midas at $787. I'll probably do the oil analysis anyways just to see how the car is doing, thanks for the suggestion. Last edited by londonfog; 02-05-2013 at 01:09 PM. |
#5
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So the front catalytic converter is fine, but the one in the rear is the one that needs replacement? They are asking too much to replace that rear catalytic converter. You can find one on ebay for less than $200 and just do the job yourself. I'm sure there are plenty of people on this forum that can help you with the procedures.
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#6
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Only the CAT in between the sensors will trigger the dtc P0420. Any CAT downstream not monitored will not trigger the dtc. If you live in emission clearance states like California and 9 other states that have adopted California emissions standards, go to a smog testing station or any shop that offer exhaust gas analysis.
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Tags |
2005, 35se, altima, code, exhaust, p0420, passenger, side, smoke, white |
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