altima 2002, 2.5 ( engine oil consumption)

[quietsoul]

Hi. I have Altima 2002, 2.5 L and there is 99000 mileage on it. I bought it like 10 days ago and I have been noticing serious problems even the mechanics can’t know it. My biggest problem is the engine oil consumption; I have to add oil every two days which is something annoying. I went to two mechanics; the first one told me that he couldn’t find any leak or smoking. He tried to figure out the problem but he couldn’t. The second mechanic said, maybe the tap wasn’t tight well which makes the oil flooded by adding much oil. He took off the engine cover to observe the car for two days but he still can’t verify the problem. I have appointment with him on Tuesday. Hopefully, he can fix it. I went to Nissan Agency and they told me you have to change the engine because it is a common problem ,If it is a common problem why do they sell their cars to us??I can’t return the car back anymore. I really need your help guys. I want u to advise me about this situation and how can I fix it?I have another question, what type of oil should I use? Now I’m using 10 W30 which made the oil consumes slowly. Is it good?How many galloons should I fill my car with? And what type of fuel and how many miles can I drive with full fuel?

My best regards

[audtatious]

There are numerous reports of "blowby" where some amounts of oil gets through the system and is burned through the intake. Usually this is a small amount. Additionally, there are numerous cases of the upper cats breaking down in the exhaust system. The 2.5l motor has a small amount of valve overlap which means there are instances where the intake and exhaust valves are somewhat opened at the same time, thus there is a small chance that debris from the cat breaking down could be injested into the motor which could cause damage to the cylinder wall and create excessive oil consumption.

I would contact your local Nissan dealership to see if the car has been in for numerous repairs (they should be able to search by VIN). If the worse-case scenario is damaged cylinder walls due to the cat breaking down then there is usually something that caused it such as bad injectors, bad airflow meter, sensors, etc.

[quietsoul]

thanx so muchbut I already went to Nissan Agency and they told me that there is a internal consumption failure and also there is a problem with catalytic converter.As a result, they told to change the engineI'm really confused.

[audtatious]

Catalytic converter failure probably means the upper cats broke up. These motors have pre-cats in the upper exhaust pipe which looks kinda like a honeycomb. If these break up they will fall and block the main catalytic converter. In the QR25 motor you also have the possibility of these breaking apart and getting into the cylinders which seems to be the issue you are having.

Unfortunatly, a new motor is about all you can do.

[quietsoul]

how much are the piston rings? or the cats?do u think it is better to change themI can't sell the car now ...I need it

thanx

[audtatious]

I honestly don't know about engine part costs. The cheapest way is to find a lightly used motor at a junk yard and pay someone to swap it in. Of course, you cannot be totally sure that motor does not have issues either.

Catalytic converters (aftermarket) are not really that expensive and can probably be found on ebay

[MaximA32]

According to All Data, a motor from Nissan costs about $2800 and approx 12hrs of labor. I'm guess-timating here but that means labor costs would be about $1200. That would but you at about $5k to have a new(ish) motor insalled with labor. Keep in mind that price doesn't include gaskets, fluids and all other incidental peices parts.

[audtatious]

And getting a used motor and having it installed would possibly be 1/2 that cost. You'd have to call around to see if you can find one and then find a mechanic who will put it in for you.

[CPS]

I'd say the cat caused the problem. The 02's were notorious for sucking in power valve plate screws, which bounced around inside the engine then shot into the cat. The cat breaking up and getting sucked back into the motor is very common. If you attempt to rebuild it you are looking at way more trouble than it's worth.

And good luck trying to find a dealer that will do a motor for 12 hours. Most of them charge 20-24. You might get an independent shop that will quote it for 12, but you'll end up paying more than 12 because if you don't know what you're doing it can take a long time.

[audtatious]

It's unfortunate that Nissan really screwed up the design of this motor.

[64dodge540]

ok I can tell you some pricing. You can find a low mileage motor for around 1200.00-1400.00 dollars depending where you look and for how long. Me, I found a 2.5L motor with 26,000 miles on it for $850.00 for my car. The precat convertor cost me before the bought the motor 440.00 but I seen another nissan dealer with a quote for 367.00 after a purchased mine.