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Discussion Starter #1
So for a couple weeks my Alti has been throwing codes having to do with high volts on the Bank 1 sensor 2 location. I thought that was the entirety of my situation so I wasn't too worried since quite some time ago I had headers put on and there are no more cats on this vehicle -rendering the O2 sensors just something to keep the ECU fooled.

Right at 2 weeks after I noticed this code I started smelling something like glue in my car and I couldn't figure it out, I popped the hood on several occasions however I couldn't find anything to make that happen and started mentally linking it up to the high volts code I was getting (melting plastic maybe?) So I ordered a new O2 sensor in case this became a replacement issue.

Yesterday I had to run out of here to a site 50 miles away . Right as I was getting into the town I started hearing what sounds like a power steering pump low on fluid and straining to make a turn in this condition. The noise continued consistently and I mentally freaked-out because I thought "she" was about go on me. Then I got to the first green light and I saw brief puffs of white smoke coming up and disappearing. So I decide to drive it to site a few more miles and deal with it after my job. I take it to a garage after my job and they later tell me that my valve covers are leaking into my alternator. The valve covers were done about 5 years ago so I really didn't suspect them since they aren't a high maintenance part usually and I couldn't find any oil leaking on the ground . Turns out the oil probably dripped directly into the alternator and cooked off. Now my alternator whines all the time, but still runs. He also told me my rack was leaking and that he had to top it off yesterday. I scratched my head because I looked at the level before I took it in. When I looked at the PS reservoir this morning the car was cold and the reservoir was filled all the way to the max HOT line. I just shook my head cursing literacy aptitude in this country and sucked out the added fluid so my PS wouldn't explode.

Anyone know if it's possible to clean up a alternator in this condition. I shined a flashlight down into it and allot the wires were no longer copper colored but instead a steel gray shade. Are the bearings sealed in alternators? Can I try to degrease it? Also, if a valve cover leaks, do you buy more valve covers or just fix the gasket seal? I normally wouldn't ask that question, however having replaced them in the last 5 years I wasn't sure of the protocol now that they've been changed once. I can't even find a maintenance cycle list for valve covers online.. so any help would be appreciated.
 

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09 Altima 3.5SE 6MT Sedan
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You should probably clean the bushing end of the alternator (where the carbon brushes make contact with the rotor). Alternator bearings should be sealed, so start with a water based degreaser before working up to something like brake cleaner as a last resort.

If there's any oil on the pulley, you should clean/degrease all that and you may have to replace the belt too if saturated.
 

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Discussion Starter #3
Thanks for the quick response Doug, any idea which way to go on the valve covers? I'm having it all looked at tomorrow AM.
 

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09 Altima 3.5SE 6MT Sedan
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I'd stop the valve cover leak, that can't go anywhere good. As for the alternator....if it keeps working, you might escape having to fix it for a while once all the oil and crud burns off/wears off. Keep an eye on the battery light though.
 

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Sealed bearings are not as sealed as people think. If you only get incidental amounts of fluid around them they are OK but if you soak them in fluid it WILL get in. I rebuild sealed bearings and soak them in fuel it gets in in only 2-3 seconds. The seal covers are simply snapped in. I pull them and clean out bearing of old lube and then relube and snap cover back on. Free bearing up to $60.

Oil leaking into an alt is OK for a while until the oil begins to burn, it turns into carbon and along with the carbon already in it (used oil from motor) it then shorts parts out. Oil by itself clean will not carry much volt but change it to carbon and it shorts pretty quick.

I rebuild alts too.

If the valve cover is plastic then check it for cracks and some need to be changed if old enough the plastic has turned into carbon (like the oil) to easily shidel off pieces of it with a fingernail. Plastic VCs do not hold gaskets nearly so well as metal ones do, I don't know why but it is a definite thing. Probably due to more warping with heat to relax on the gasket.
 

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09 Altima 3.5SE 6MT Sedan
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B1S21 is the O2 sensor monitoring your cat efficiency. B1S1 is your Air/Fuel mix sensor.
 

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Discussion Starter #8
Hey Doug, I appreciate the reply.. I mean who would answer if you didn't right? hah.
I just thought I'd remind you though that I'm not a mech, I pretend to be when I don't want to front the cash for someone else to work on my car. That said, all I know at this time is that a Sensor 2 is considered "downstream" as in "After the engine". The link I provided is clear enough, but I don't have manifolds or cats so my setup looks a bit different than the illustrations. It was also confusing to me that above on the main diagram that shows all locations, it shows sensor 2, Bank 1 as the last sensor in the line. Whereas below, on the close-up illustrations of the locations it is shown next to the oil pan -which is fairly close to the front of the vehicle. In other words, you're going to have to reply to me like I'm 5. Once I've got something, I've got something, but getting it in there is some kind of adventure...
 

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09 Altima 3.5SE 6MT Sedan
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Hey...no worries...I don't write novels if I don't have too...but not scared to go a bit more verbose :)

So, here's the basic layout:

Thottle body-->cylinder-->BankXSensor1->Precat->BankXSensor2->Catalytic Converter->Tailpiper->Muffler

BxS1 is used to adjust the duty cycle of the injector to ensure efficient combustion mixture
BxS2 is used to monitor the efficieny of the precat (small catalytic converter, located close to engine so it heats up faster)

Usually with a straight downpipe or gutted precat, BxS1 stays unchanged (btw this is the heated, upstream sensor). BxS2 usually needs some antifoulers or other cheater mechansims to mimic the effect that the precat would have had on the exhaust gases. BxS2 will be located right after the precat element, so still fairly close to the top of the engine.
 

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Discussion Starter #10
Oh Doug, very NOT for a 5 year old to understand. I'm guessing your short-hand "x" is your way of including both Bank 1 & 2 interchangeably so it saved you some writing... Ok how about this?
Using the link to NissanHelp.com in my post above, this one--> 2002-2004 Nissan Altima with 3.5 Engine O2 Sensor Location | Nissanhelp.com . Tell me what sensor it should be. I'd say circle it, but you'd have to bring up Snipping Tool in Windows, draw on the illustration and re-save the pic and attach, which is a hassle.
 

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09 Altima 3.5SE 6MT Sedan
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100406
 

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Discussion Starter #12 (Edited)
So I looked into my issue the other day. I knew the set-up was going to look a bit different than the illustration so I just decided the best I could do was get under there and find the Bank 1 headers, trace this to the first sensor and then follow it downstream to get to the sensor 2. In reality that was the most confusing part as it was, the 2 downstream sensors were side by side on the same section which left me wondering which sensor to play with. When I took my car back to the shop for a timing advance code my car was giving me, (where I got the alternator and vaIve covers replaced) I asked the mechanic which sensor it was but never got a straight answer from him. I had remembered that he told me he checked it out the 1st time I brought it in, but that was when he gave me the shit news that my alternator was no longer charging the battery (stupid plastic valve covers).

So I do something with my 02 sensors, I wrap the connection harnesses in aluminum foil; it tends to keep the plastic cleaner, more protected and easier to remove. It also showed me which sensor it was because the guy unwrapped it and as it is with aluminum foil it never quite wraps back as tight as the first time you put it on. I pull the harness connector apart and my problem was obvious. There was lots of green corrosion on the pins as well as in the holes. Since I already purchased a new sensor I decided to use it to take care of half the corrosion. I figured I could probably clean the old one up and have it as a back-up sensor if needed. I didn't have any brake cleaner left, just WD-40 that I didn't want to use so I grabbed some of my computer alcohol wipes for electronics and squeezed some drops into the holes while shoving a few wire bristles from a wire brush in and out of the holes to scratch off as much green as I could from the female end of the connector. So far it seems to have paid off. The code hasn't come back for a day, I'm keeping my fingers crossed always half-expecting that light to pop back up on my dash. I'm hoping to make it to 200K with this car, but the problems come in groups now, a feeling a bit like a dam with ever replenishing new leaks and me running out of fingers to stop the flow with. But that is for another post or I'd effectively hijack my own problem thread.

Btw, as it turned out the Bank 1 Sensor 2 location is on the passenger side of the exhaust system and the Bank 2 Sensor 2 location is on the Driver side of the exhaust system.
 

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09 Altima 3.5SE 6MT Sedan
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Good job, thanks for the detail provided...will definitely help others.
 
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