# 2.5 L Pre-Catalytic Converter Question



## FrontierFred (Sep 18, 2015)

Hey, everyone.

I love my 2017 Fronti (2.5L SV King Cab AT). It's my second Fronti. However, I recently read there can be issues with the pre-catalytic converter that's built into the exhaust manifold of the 2.5 L engine. Apparently, the ceramic material can break up over time and get sucked back into the motor. Has anyone else heard of this? Just wondering if it's a problem only with older models (similar to the radiator fluid mixing with the tranny fluid issues the 4.0L engines used to have but are now fixed).

I tried my best search techniques but couldn't find anything in the forums. Thanks in advance for any info.


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## quadraria10 (Jul 6, 2010)

Tended to affect earlier versions of the qr25de engine. And even then to the best of my knowledge mainly affected Sentra SER models around 2002 to 2004.

Here is an article that explains it somewhat. 

2002-2006 Nissan Altima 2.5L (QR25DE engine) Seeing bluish smoke and Code PO420? ? Auto Repair Instructions

I have a 2006 X trail with the 2.5, no such problems after 11 years and 195,000 kms. Does not burn oil, no leaks, exhaust all still original. Been great and still gets good mileage. I don't think it should be a worry for you.


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## BRubble (Jun 22, 2014)

FrontierFred said:


> Hey, everyone.
> 
> I love my 2017 Fronti (2.5L SV King Cab AT). It's my second Fronti. However, I recently read there can be issues with the pre-catalytic converter that's built into the exhaust manifold of the 2.5 L engine. Apparently, the ceramic material can break up over time and get sucked back into the motor. Has anyone else heard of this? Just wondering if it's a problem only with older models (similar to the radiator fluid mixing with the tranny fluid issues the 4.0L engines used to have but are now fixed).
> 
> I tried my best search techniques but couldn't find anything in the forums. Thanks in advance for any info.


After reading the article that Quadraria posted, it seem's that oil consumption may play a role in this.

There are a few thing's that an owner can do to help prevent oil consumption and this is what I have tried to do since at least '73.

1. Follow the breakin period as advised in the Owner's Manual.
2. Use the recommended Viscosity Weight and Type of Motor Oil recommended in the Owner's Manual for Your Temperature Region.
3. Allow the engine to warm up until the Engine RPM's fall to normal Idle speed or at least about a minute at normal warm engine idle speed.
4. Keep RPM's at or below 1750 for the 1st 10 mile's, and be easy on takeoff's from stop's like at traffic light's.
5. Try not to ever go over 4K RPM's and better if you can not go over 3K RPM's.
6. Change the engine oil/air filter at the recommended interval's ie Time and/or Mileage, whichever come's 1st. Never neglect the Air Filter.
7. Alway's use a Nissan OIL Filter.
8. Keep everything Stock/OE in regard's to the Engine and Exhaust System. Might be able to substitute catalytic converter's though in an effort to be able to be afford, if or when that is ever needed.

My local Nissan Service advisor recommended that I use Mid Grade Gas,, as it is easier on the Valve's(I currently have a V6 Frontier).

Prior to this V6 I drove a 2.4 Hardbody for 20 year's and at 175K mile's the engine wasn't burning any oil and the engine was still very quiet.

I also drive with the objective to get good MPG, which is easy on the gas,, and easy on the brake's,, which will also help the engine and brake's last longer.

Regards,


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## quadraria10 (Jul 6, 2010)

Best wishes for the holidays BRubble.
Good break in tips for his 2017. I just haven't seen anything here about that particular issue with the newer gen qr25de engines.

I confess I have never used a Nissan Oil filter on mine. Have always used Purolator or Bosch oil filters, and for the past four years Mobil 1 synthetic oil which I now change twice a year and go somewhere between 8,000 and 10,000 kms between changes.


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## smj999smj (Jan 1, 2006)

The issue was with the first few years of the QR25DE engine which appeared in the 2002 Altima and Sentra SE-R. The issue was caused by the engine management programing of the ECM which caused the deterioration of the catalyst substrate. Because these engines used the variable valve timing to accomplish EGR by cracking open the exhaust valve during the intake stroke (rather than use a conventional EGR valve design), tiny particles of the substrate could get sucked into the combustion chambers where they would score the cylinder walls and create a poor piston ring to cylinder wall sealing condition, resulting in an oil burning engine. The issue was serviced under a recall, but not all of those engines received the recall or they received them but it was a little too late and they ended up having problems, anyway. A lot of those vehicles were given either new short-blocks or (later) long blocks as part of the recall. I haven't heard of this being an issue on any Frontier I4's. 
The oil filter didn't have anything to do with the issue and you don't have to use a genuine Nissan filter on your vehicle, but still should use a quality filter and, more importantly, service the oil as recommended by the manufacturer. Personally, I do use Nissan filters most of the time; if you buy them in bulk (I have three Nissans that all use the same filter), like a case of 12, you can usually get a little bit of a discount if you talk to your Nissan dealer or buy them online from a place like CourtesyParts.com or NissanPartsDeal.com. I get the drain plug washers by the bag, which fit both the oil pan and trans pan drain plugs, from Ebay. You can get them in bags of 10, 20, 30, 50....whatever you need...and a lot cheaper than getting them from Nissan. Just search "Nissan 11026-01M02."


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## FrontierFred (Sep 18, 2015)

Thanks, everyone. Good stuff.

I haven't changed the oil on a Fronti 2.5L before. From what I've read, the oil filter on the 2.5L is behind a rubber shroud (instead of a metal access plate on the 4.0L). Do you need to remove the shroud? Or can you simply move it out of the way?

Thanks a bunch!


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## BRubble (Jun 22, 2014)

quadraria10 said:


> Best wishes for the holidays BRubble.
> Good break in tips for his 2017. I just haven't seen anything here about that particular issue with the newer gen qr25de engines.
> 
> I confess I have never used a Nissan Oil filter on mine. Have always used Purolator or Bosch oil filters, and for the past four years Mobil 1 synthetic oil which I now change twice a year and go somewhere between 8,000 and 10,000 kms between changes.


Thanks Quadraria,

I just put my trust in Nissan on the Oil Filter, so it's one less mistake for me to make when doing maintenance. Like SMJ, I get the Nissan Filter's on either Amazon or Ebay, and they usually come from a Nissan Part's Department that are selling at a Discounted price.

I've thought about useing Synthetic, but I'm down here in the Deep South by the Gulf, which doesn't get very cold down here, and I'm retired,, so I don't drive very much. So far I've decided to stay with Castrol GTX 5w30, but for about the same price,, I could get WalMart's Supertech Full Synthetic 5w30 for about the same price. That's what SMJ is useing the WalMart Supertech Full Synthetic. If I lived up in the North Country though,, I'm pretty sure that I would be useing Full synthetic, because of the ability for full synthetic to pour better, even @ the same viscosity of Dino Oil. This is what I've read,, but don't know for a fact about the pour point. Another reason,, since I don't drive very much, is that I've read, that Synthetic tend's to run off parts faster, compared to dino that tend's to leave a film of oil longer on the parts. Again just what I've read,, and don't have any fact's. I do have one small engine Brigg's and Stratton that calls for full synthetic,, so that's what I use in that engine, because B&S recommend's it.

Best Wish's to You as well,, and Hope Santa bring's you just what you want. Amazon and Ebay are Santa's Helper's. 



> Thanks, everyone. Good stuff.
> 
> I haven't changed the oil on a Fronti 2.5L before. From what I've read, the oil filter on the 2.5L is behind a rubber shroud (instead of a metal access plate on the 4.0L). Do you need to remove the shroud? Or can you simply move it out of the way?
> 
> Thanks a bunch!


Fred,

I'll have to defer to someone else that has the 2.5L on Removeing/Installing the Oil Filter. On my V6 I just read the Owner's Manual,, as well as the Service Manual and then developed my own method. I don't know why Nissan make's it difficult for VQ40DE 4L owner's to remove/replace the oil filter. Apparently the Man or Woman that designed the Oil Filter Access has never done his/her own oil change's. But I shouldn't complain, cause it wasn't that easy on the 2.4L I4 Hardbody that I had for 20 year's either. 

I hope it is easier on the 2.5L for you to do. The Service manual for our Truck's is a Free Download on the WWW. Just Google Frontier Service Manual,, and you'll find a free download somewhere.

Enjoy Your New Frontier and Happy Holiday's.


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## smj999smj (Jan 1, 2006)

I don't even bother with the oil filter access panel on the front skid plate on my 06 & 08 Pathfinders, anymore. I just remove the whole skid plate out of the way. It's a few more bolts, but makes access a lot easier and I can do a better job cleaning off the residual oil.


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## BRubble (Jun 22, 2014)

smj999smj said:


> I don't even bother with the oil filter access panel on the front skid plate on my 06 & 08 Pathfinders, anymore. I just remove the whole skid plate out of the way. It's a few more bolts, but makes access a lot easier and I can do a better job cleaning off the residual oil.


Me too, and it also let's me get a better look at what's going on under there as well.

Happy Holiday's SMJ, Here's hopeing You and Your's have a Great Christmas.


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## FrontierFred (Sep 18, 2015)

FYI, I expected I'd have to crawl under the truck to find the oil filter, and I haven't yet had time for that. But then yesterday I figured I'd open the hood and specifically check if I could see it from above. Sure enough, it's right there in plain sight on the passenger side of the engine. Then I took a quick look under the truck and found the oil drain plug right away. Overall, seems like a relatively simple process. Nothing seems to be in the way of anything.

Thanks again everyone for the assist!


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## BRubble (Jun 22, 2014)

FrontierFred said:


> FYI, I expected I'd have to crawl under the truck to find the oil filter, and I haven't yet had time for that. But then yesterday I figured I'd open the hood and specifically check if I could see it from above. Sure enough, it's right there in plain sight on the passenger side of the engine. Then I took a quick look under the truck and found the oil drain plug right away. Overall, seems like a relatively simple process. Nothing seems to be in the way of anything.
> 
> Thanks again everyone for the assist!


While you got the hood open,, coat the Battery terminal's with Grease to prevent corosion. Been doing that for over 30 year's; Cheap, Fast, and It Work's.

Regard's


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