was reading on a nissan forum, one user said that the 4 cyl. engines (QR25DE, as the one i have in my car) are hard on oil and that the mobil 1 5W30 tends to shear down to a 5W20 when run hard in these engines. said the mobil 1 is too thin. many people said the mobil 1 0W40 would be better, as most of the time it shears down to a 30 wt. recommended viscosity for my car is 5W30, and iven been using Mobil 1 5W30 with no problems, it just concerns me after i read that. i run the car fairly hard, always let it warm up though, before any hard running, also has a coolant leak(paid 1,000 for the car due to a paint defect, dont want to really put any money into the head gasket as it runs fine now) in the #3 cyl although the car runs fine, just have to add coolant every so often to th overflow bottle. does not smoke at all. jus got a used oil analysis from blackstone, had a small concentration of potasssium and sodium i nthe oil, so my coolant leak suspicion was confirmed.these 2.5 engines ar notorious for having many problems, and i cant believe mine has survived 25,000 miles of hard abuse since ive owned it. just wondering if the mobil 1 0W40 would be a good oil to use in my car.
nissan 2.5
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if it's the original engine and you have 25k, you're doing good.. at around 45-60k expect the CEL to light up and give you a catalyst below threshold code that the only cure is a new motor.
There are a lot of issues with this motor, but once they're addressed it's pretty solid.
I've run Mobil Clean 5000 and Clean 7500 (summer) exclusively since 19k. It does go thru oil pretty fast on the new engine, almost 100k on it.
the o2 bung plug on the cat had shoddy welding and caused a leak as well, dealership only cat
Oh.. California cat for that matter.. took a few hours to swap out.. have to remove the alternator to do it. But it's just nuts & bolts.
the cam sensor is a major issue.. the fix was to reprogram the car computer to ignore the excessive errors that were read. Car's been fine since.
I still run 5w30, still using mobil clean 5000 (have 1 case left), wix oil filter, did a MMO cleanup last winter.. so far so good.
There are a lot of issues with this motor, but once they're addressed it's pretty solid.
I've run Mobil Clean 5000 and Clean 7500 (summer) exclusively since 19k. It does go thru oil pretty fast on the new engine, almost 100k on it.
the o2 bung plug on the cat had shoddy welding and caused a leak as well, dealership only cat
Oh.. California cat for that matter.. took a few hours to swap out.. have to remove the alternator to do it. But it's just nuts & bolts.
the cam sensor is a major issue.. the fix was to reprogram the car computer to ignore the excessive errors that were read. Car's been fine since.
I still run 5w30, still using mobil clean 5000 (have 1 case left), wix oil filter, did a MMO cleanup last winter.. so far so good.
The QR25DE did have some issues. http://en.wikipedia.org/wiki/QR25DE does a pretty good job providing a a brief overview.
If the current QR25DE is hard on oil, mine certainly isn't showing it. But I'm pretty easy on it and drive mostly highway miles. Check out my used oil analysis at the following link:
https://bobistheoilguy.com/forums/threads/castrol-edge-5w30-6k-miles-08-nissan-qr25de.140902/
Based on the results, I ran the subsequent fill of Ultra for 7,500 miles and plan to do the same with my current fill of it. Then I'll get another used oil analysis.
If the current QR25DE is hard on oil, mine certainly isn't showing it. But I'm pretty easy on it and drive mostly highway miles. Check out my used oil analysis at the following link:
https://bobistheoilguy.com/forums/threads/castrol-edge-5w30-6k-miles-08-nissan-qr25de.140902/
Based on the results, I ran the subsequent fill of Ultra for 7,500 miles and plan to do the same with my current fill of it. Then I'll get another used oil analysis.
Don't worry about viscosity shearing if you aren't even extending your OCIs anyway.
After 2007 the QR25DE was revised and all of the previous problems shouldn't exist period. Constant adjusting and revising is a common thing to expect from Nissan.
My 2011 Nissan Sentra SE-R Spec-V (QR25DE HO) also hasn't shown any signs of issues either. I suspect that the Spec-Vs have some serious baffling though as draining oil only provides a little more than a gallon.
After 2007 the QR25DE was revised and all of the previous problems shouldn't exist period. Constant adjusting and revising is a common thing to expect from Nissan.
My 2011 Nissan Sentra SE-R Spec-V (QR25DE HO) also hasn't shown any signs of issues either. I suspect that the Spec-Vs have some serious baffling though as draining oil only provides a little more than a gallon.
i meant ive put 25,000 hard miles on it since ive owned it, bought it with 89k in january 2010 and i now have 114k. i got rid of the cat problem i put a header on it back in november (alternator was a pain, bottom bolt was so tight i rounded off the bolt head, even using a 1/2 drive breaker bar!)just trying to find the best oil for the QR25.
my car is a 2002, first year with the 2.5
You had a good UOA with the Mobil 1. I am sure you could run Pennzoil conventional (or any major conventional on sale) and continue to breeze through as long as you change the oil at around 3k. No need to run Mobil 1 0w40 or any expensive oils with your short intervals. (I seriously recommend short intervals anyway).
Son has a 2006 and the engine was replaced by the manufacturer before it was sold new at the dealership, warranty is 100,000 miles. He purchased used at 58,000, runs great absolutely no issues, I change his oil and have been using Amsoil 0W30, Mobil 1 0W30 and Shell Synthetic 5W30 with at least a 6000 mile OCI. Seems to be relatively easy on the oil IMO.
spector, you might want to look into a header that replaces the factory exhaust manifold, sooner or later it will cause oil consumption problems, i fixed mine at 103k right when the cat in the manifold was starting to give me problems
I use only 5W30 and 10W30 in my '04 2.5S without any issues but also drive normaly. I do have several questions about the front converter since it's been brought up in this post. I realize these questions are for the Maintenance Section but, I'd like to ask them here if that's alright?
OK, so let's say I just want to change out the front converter in my '04 Altima 2.5S with another brand converter. I have heard of this issue only recently(past year or so) and understand that these front converters can break up inside themselves and cause major engine issues. I've had no trouble as of yet(owned since new).
I can't nor do I want to install headers in my Altima as per State Inspection Laws. Needs a converter! Maybe the new Headers come with a new converter, as well IDK but, I still don't want them. My experience with header in vehicles over the past 40 years has been nothing but issues...Cracking, discoloring, have to modify to install, etc, etc, etc.
My questions are:
What after market brand converter should I use?
Have there been any dealers replacing any of these converters under a TSB(should customers complain)?
Was the '04 effected by these faulty converters(or just '02-'03)?
Was there a recall on these converters?
OK, so let's say I just want to change out the front converter in my '04 Altima 2.5S with another brand converter. I have heard of this issue only recently(past year or so) and understand that these front converters can break up inside themselves and cause major engine issues. I've had no trouble as of yet(owned since new).
I can't nor do I want to install headers in my Altima as per State Inspection Laws. Needs a converter! Maybe the new Headers come with a new converter, as well IDK but, I still don't want them. My experience with header in vehicles over the past 40 years has been nothing but issues...Cracking, discoloring, have to modify to install, etc, etc, etc.
My questions are:
What after market brand converter should I use?
Have there been any dealers replacing any of these converters under a TSB(should customers complain)?
Was the '04 effected by these faulty converters(or just '02-'03)?
Was there a recall on these converters?
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was reading on a nissan forum, one user said that the 4 cyl. engines (QR25DE, as the one i have in my car) are hard on oil
The 2.5L being "hard on oil" seems like a deja vu topic here, iirc. In my 8+ years/~85k miles experience with a 2.5L Altima, the engine is NOT "hard on oil". The engine ran fine on 5w30 and there is my used oil analysis showing excellent results using Valvoline conventional posted on the used oil analysis board to back it up. The engine used virtually no oil at all.
Of course, that all changed dramatically when the precat disintegrated spewing substrate which was sucked into the engine. The rest is history for me an thousands of other 2.5L owners.
IMO, with your current head gasket leak, and the 2.5L's history, you would be wasting your money on Mobil 1 0w40 or any other expensive synthetic oil. My advice, run any inexpensive name brand dino, 5-30, 10w30 or hdeo until the engine expires or you get the head gasket fixed, whichever comes first.
At this point I don't see choosing any synthetic oil as the answer to increasing your engines longevity.
was reading on a nissan forum, one user said that the 4 cyl. engines (QR25DE, as the one i have in my car) are hard on oil
The 2.5L being "hard on oil" seems like a deja vu topic here, iirc. In my 8+ years/~85k miles experience with a 2.5L Altima, the engine is NOT "hard on oil". The engine ran fine on 5w30 and there is my used oil analysis showing excellent results using Valvoline conventional posted on the used oil analysis board to back it up. The engine used virtually no oil at all.
Of course, that all changed dramatically when the precat disintegrated spewing substrate which was sucked into the engine. The rest is history for me an thousands of other 2.5L owners.
IMO, with your current head gasket leak, and the 2.5L's history, you would be wasting your money on Mobil 1 0w40 or any other expensive synthetic oil. My advice, run any inexpensive name brand dino, 5-30, 10w30 or hdeo until the engine expires or you get the head gasket fixed, whichever comes first.
At this point I don't see choosing any synthetic oil as the answer to increasing your engines longevity.
charbaby, yes there was a recall on them, the dealers would just replace them with another converter of the same kind, i know, dumb right? it affected all years 02-06. the converter is in the manifold so i dont know how you would be able to replace it with an aftermarket converter. since you have emissions laws, it would seem that you would just have to stick with it, and watch your oil level, we dont have emissions tests, i just said to [censored] with it and put a cheap header
Originally Posted By: mobilaltima
charbaby, yes there was a recall on them, the dealers would just replace them with another converter of the same kind, i know, dumb right? it affected all years 02-06. the converter is in the manifold so i dont know how you would be able to replace it with an aftermarket converter. since you have emissions laws, it would seem that you would just have to stick with it, and watch your oil level, we dont have emissions tests, i just said to [censored] with it and put a cheap header
I guess what I was asking is, that I have searched for after market converters for this car and have found several. Is there any particular one better that the others in terms of quality? Or are even the after market converters going to bust up, fall apart inside themselves and cause engine problems anyway?
charbaby, yes there was a recall on them, the dealers would just replace them with another converter of the same kind, i know, dumb right? it affected all years 02-06. the converter is in the manifold so i dont know how you would be able to replace it with an aftermarket converter. since you have emissions laws, it would seem that you would just have to stick with it, and watch your oil level, we dont have emissions tests, i just said to [censored] with it and put a cheap header
I guess what I was asking is, that I have searched for after market converters for this car and have found several. Is there any particular one better that the others in terms of quality? Or are even the after market converters going to bust up, fall apart inside themselves and cause engine problems anyway?
the converter (pre cat) in the manifold isnt replacable by aftermarket, you mean the the second converter under the car?
The aftermarket options for pre-cat replacement are to replace the exhaust manifold/pre-cat as one unit. The pre-cat is just some material held in place by 2 screens. The failure is due to the screens failing and the pre-cat material being sucked into the engine.
You could also buy a manifold that does not contain the pre-cat as you do have a catalytic convertor in the car still and the car will still pass emissions. This would probably be the best option to avoid ever having to worry about this issue again. Not sure which aftermarket brand is best though. Oh and you should also gain a few horses because the pre-cat material causes exhaust turbulence.
You could also buy a manifold that does not contain the pre-cat as you do have a catalytic convertor in the car still and the car will still pass emissions. This would probably be the best option to avoid ever having to worry about this issue again. Not sure which aftermarket brand is best though. Oh and you should also gain a few horses because the pre-cat material causes exhaust turbulence.
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You could also buy a manifold that does not contain the pre-cat as you do have a catalytic convertor in the car still and the car will still pass emissions. This would probably be the best option to avoid ever having to worry about this issue again.
Do you have a reference to verify that statement? That would be highly important in states (like mine) requiring emissions. There is also an upstream and a downstream O2 sensor that have to be accounted for in any alteration of the 2.5L exhaust catalyst system. Otherwise an SES/CEL light will occur and have to be dealt with.
Whatever the case, these are all matters a 2.5L Nissan owner shouldn't have to be concerned with. But, Nissan wrote these 2.5L turds and their owners off a long time ago.
You could also buy a manifold that does not contain the pre-cat as you do have a catalytic convertor in the car still and the car will still pass emissions. This would probably be the best option to avoid ever having to worry about this issue again.
Do you have a reference to verify that statement? That would be highly important in states (like mine) requiring emissions. There is also an upstream and a downstream O2 sensor that have to be accounted for in any alteration of the 2.5L exhaust catalyst system. Otherwise an SES/CEL light will occur and have to be dealt with.
Whatever the case, these are all matters a 2.5L Nissan owner shouldn't have to be concerned with. But, Nissan wrote these 2.5L turds and their owners off a long time ago.
The upstream O2 sensor should function fine after the modification because it's before the pre-cat. For the downstream you can get a "spacer" fake O2 sensor that the real O2 sensor plugs into. So the fake sensor plugs up the socket the O2 sensor normally would be in, and the actual O2 sensor is sensing outside air so it wont throw a code.
I'll try and find a post about someone saying they have passed emissions without the pre-cat.
I completely agree that Nissan should not have released an engine with such a major fault in it. I'm sorry if it seems like I am trying to downplay a scenario that should never have happened, I am not. I do however feel that the car is not destined for the junk heap as this repair is not too expensive if you do the work yourself.
I'll try and find a post about someone saying they have passed emissions without the pre-cat.
I completely agree that Nissan should not have released an engine with such a major fault in it. I'm sorry if it seems like I am trying to downplay a scenario that should never have happened, I am not. I do however feel that the car is not destined for the junk heap as this repair is not too expensive if you do the work yourself.
Have read about spacers to 'fool' the SES system.
Whatever the case, the largest majority of 2.5L Nissan owners, including myself, were deceived into believing the recall for the precat was to fix the issue. Unfortunately, nothing could be further from the truth.
And imo, the OP's current head gasket issue is related to a failure of the precat prior to his purchase.
Whatever the case, the largest majority of 2.5L Nissan owners, including myself, were deceived into believing the recall for the precat was to fix the issue. Unfortunately, nothing could be further from the truth.
And imo, the OP's current head gasket issue is related to a failure of the precat prior to his purchase.
Same engine in a Sentra post.
"What about state emissions testing if I remove the precat?
Catalytic converters work best at high temperatures, this is why the precat sits so close to the engine, it reaches its optimal temperature quicker, thus cleaning your exhaust for the first few minutes after startup. However, the QR25DE comes equipped with a second catalytic converter located in the midpipe. This midpipe cat alone will still allow you to pass emissions after the car has warmed up. If you have a visual inspection in your state (like California) an aftermarket header will obviously cause you to fail, so your best bet is to either use the stock manifold without the precat, or just swap in the stock manifold for the inspection."
This guy passed it right after doing the header job but is confused as to why he's failing now. It's another Spec V, sorry, they seem to be more into modding than Altima owners. Same engine and same problem though. He posts the actual results though which is kind of neat.
This guy passed NJ state inspections whi...ith no pre-cat.
I realize one error in my post. I did not mean you would be able to pass California emissions without the pre-cat, I doubt you would be able to. I mean other states with not quite as strict emission standards.
Semi-related, this thread has a nice how-to.
Hope this helps.
"What about state emissions testing if I remove the precat?
Catalytic converters work best at high temperatures, this is why the precat sits so close to the engine, it reaches its optimal temperature quicker, thus cleaning your exhaust for the first few minutes after startup. However, the QR25DE comes equipped with a second catalytic converter located in the midpipe. This midpipe cat alone will still allow you to pass emissions after the car has warmed up. If you have a visual inspection in your state (like California) an aftermarket header will obviously cause you to fail, so your best bet is to either use the stock manifold without the precat, or just swap in the stock manifold for the inspection."
This guy passed it right after doing the header job but is confused as to why he's failing now. It's another Spec V, sorry, they seem to be more into modding than Altima owners. Same engine and same problem though. He posts the actual results though which is kind of neat.
This guy passed NJ state inspections whi...ith no pre-cat.
I realize one error in my post. I did not mean you would be able to pass California emissions without the pre-cat, I doubt you would be able to. I mean other states with not quite as strict emission standards.
Semi-related, this thread has a nice how-to.
Hope this helps.
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