REVscene - Vancouver Automotive Forum

tegra7 · 01-16-2012, 12:50 PM

Any other Altima people out there?

So I have a 2002 Altima 2.5s. The other day I checked the oil and notice that all the oil was completely gone. I quickly put in some oil and took it for an oil change, mechanic also did a visual inspection, said everything looked normal,no leaks underneath, but it was also low on coolant. After topping up all the fluids a couple of days a go I checked the oil this morning and it was completely black. I did a bit of research online and read some nasty issues with the QR25DE motor. Precat breaks apart resulting in debris going into the motor, excessive oil & coolant consumption, head gasket failure and the list goes on.

I've noticed my precat making a rattling noise at times and I am looking for an aftermarket header to replace it. My question is, if I replace the precat with a header and flush some of the crap out of the motor, will excessive oil consumption stop or atleast get better? I should also mention, it does blow smoke under hard acceleration.

Another Issue I'm having with this vehicle is a slight misfire when starting. Engine starts and sputters a little but after I give it some gas it idles fine.
I've also noticed lack of acceleration under 3k rpms.

EDIT:I spoke with Nissan and they tell me all recalls were up to date on this vehicle. They say the oil consumption is caused by debris from the broken pre cat is scoring the cylinder walls and that I need to replace the precat & the motor for 5k. Yeah right.

5er · 01-17-2012, 10:17 AM

Yeah a bunch of sentras had engines replaced... I had 3 warranty engines. It takes longer to show-up on the automatic cars. Down shifting amplifies the problem... the cat gets fuel in it, gets hot, breaks up, sucks particals in engine... scores cylinder walls, then new engine.

5er · 01-17-2012, 10:22 AM

The starting issue is likely a bad cam or crank sensor, cam is easy, crank is awkwardly behind the engine.

5er · 01-17-2012, 10:25 AM

I have a brand new pre-cat for a sentra.. $50 if it helps. Not sure if they are the same on an Altima, you'll have to do a bit of research.

5er · 01-17-2012, 10:26 AM

Pretty much sell the car

unless you love it.

tegra7 · 01-20-2012, 11:06 PM

Quote:

Originally Posted by 5er

Yeah a bunch of sentras had engines replaced... I had 3 warranty engines. It takes longer to show-up on the automatic cars. Down shifting amplifies the problem... the cat gets fuel in it, gets hot, breaks up, sucks particals in engine... scores cylinder walls, then new engine.

But can the pre cat still be broken even if my car's not throwing a code for a bad cat converter?

GotRice? · 02-04-2012, 10:03 PM

yes... if u go on the sentra forum all 02-06 se-r and spec v owners will tell u to get a aftermarket header with no cat or get aftermarket no cat header and get a muffler shop to weld a cat further down the system to prevent the problem... and there is the famous butterfly screw problem on those QR25DE engine... the butterfly screw will unscrew itself, i guess from vibration and goes into the cylinder and scratch the sh!t out of it...

GotRice? · 02-04-2012, 10:10 PM

head gasket on those QR25DE motors usually last around 100,000km but that depends how u drive... some people had way over 100,000km without any head gasket problem..

tegra7 · 02-05-2012, 03:46 PM

Quote:

Originally Posted by GotRice?

yes... if u go on the sentra forum all 02-06 se-r and spec v owners will tell u to get a aftermarket header with no cat or get aftermarket no cat header and get a muffler shop to weld a cat further down the system to prevent the problem... and there is the famous butterfly screw problem on those QR25DE engine... the butterfly screw will unscrew itself, i guess from vibration and goes into the cylinder and scratch the sh!t out of it...

Quote:

Originally Posted by GotRice?

head gasket on those QR25DE motors usually last around 100,000km but that depends how u drive... some people had way over 100,000km without any head gasket problem..

Ya, I dropped the car at the mechanic yesterday to get a used motor installed. Newer motor has a stamp on the side indicating it was re manufactured by Nissan in 2007,has approx 60,000km on the rebuild.

I told the mechanic to loctite the butterfly screws & I got a catless header for it.

Fingers crossed.

GotRice? · 02-05-2012, 08:13 PM

that should solve the problem for the QR25DE but no one can stop that head gasket problem... u just hav to treat the engine like a baby... cuz i had no problem with mine after replacing the head gasket, butterfly screws and catless header... i still need to go hollow out my oem cat so i can get thru the aircare visual inspection, thats if they do look under the hood, but as for the OBDII scans i should pass with flying colors with the O2 sensor spacer...

DK33 · 02-09-2012, 02:35 PM

I feel your pain. MY POS QR25DE Altima... Engine lost compression, get it checked out my engine is dead without any sort of sign... Got a new engine... 2 days later the alternator went... A week after I changed the alternator, the driver's side window motor went, and then a month after that the belt tensioner and belt need to be change because started to squeal... FML! On top of that I spent money on buying the aftermarket header and getting it installed. *sigh*

chris_89T · 05-21-2012, 03:28 PM

Blown head gasket. Common on the 2.5 Especially 02-04.

While the motor is out id replace both the crank sensor on the back of the motor. There a ticking time bomb and will leave you stranded at the worst time. Atleast if your not going to replace it make sure there is no oil in the connector. If there is replace it, because if it isnt causing a problem now it will soon.

Inspect the Cat prior to installing the stock header. that rattle could be the cat falling apart, but there is also a bracket that secures the cat to the block that rattles itself loose.