In 2001, Nissan began mass-producing the QR25DE engine. Many Nissan models, including the Altima and Rogue, will still use the QR25 2.5L engine in 2021. The engine’s design is over two decades old, so it’s undergone numerous updates to boost performance, reduce emissions, improve fuel economy, and ensure long-term reliability. However, they are all based on the same QR25DE engine code and have the same basic design.
Nissan’s use of the 2.5 inline-4 for the past two decades shows how reliable the engine is on all counts. However, no engine is faultless, and this is no exception. The reliability, specifications, and other aspects of the Nissan QR25DE engine are covered in this article.
What Cars Use the QR25 Engine?
These Nissan 2.5L I4 QR25DE engines can be found in the following years and vehicle makes:
- 2005-2019 Nissan Frontier
- 2002-present Nissan Altima
- 2007-2011 Nissan Altima Hybrid
- 2003-2016 Nissan Murano
- 2008-present Nissan Rogue
- 2002-2012 Nissan Sentra SE-R & SE-R Spec V
- 2002-2020 Nissan X-Trail T30 / T31 / T32
The 2.5 inline-4 engine is also used in a number of other international models. Because it’s more difficult to find specific models from certain years, we skipped over a few.
Nissan QR25 2.5 Specs
Nissan’s QR engine line includes the QR25DE. The number 25 refers to the engine’s displacement, which is listed as 2.5 liters. DOHC is denoted by the letter D, while multipoint fuel injection is denoted by the letter E. For this reason, a QR25DE code is assigned to the 2.5 inline-4’s VIN number. The following are the specifications for Nissan’s QR25 engine:
|Displacement||2,488 cc (2.5L)|
|Bore x Stroke||89mm x 100mm|
|Compression Ratio||9.5 : 1 to 10.5 : 1|
|Torque (lb-ft)||173-180 TQ|
It’s important to remember that the QR25DE has been in existence for over two decades now! Over time, it has undergone numerous updates due to being a long-running production engine. The 2.5L engine is now in its 4th generation, according to the manufacturer. Despite the updates, the QR25DE’s basic design remains the same, which is why the engine code is also the same.
These are standard specifications for an inline-4 in today’s world. The QR25 has a lightweight aluminum block and head. Due to its DOHC architecture, it has excellent efficiency and power output. The Altima and most other Nissan models have between 175 and 182 horsepower. However, based on the year and model, horsepower ranges from 152 to 200.
2007+ QR25DE Engine
It was 2007 when the QR25 2.5L inline-4 engine received a significant update. A few of the modifications help fix the engine’s original problems, while others boost power, reduce fuel consumption, and reduce emissions. In 2007, the QR25DE engine received the following improvements:
- Manifold with a single path intake of greater diameter
- Piston crown shape has been revised to accommodate higher compression levels.
- New pictures and videos have been added to the cam profile.
- Additional friction-reducing coatings for the piston, bearing, and other moving parts
- A second engine mounting bracket
- A higher top speed and hp limit
An issue with the QR25DE intake manifold will be discussed. This affects Nissan Altima models from 2002 to 2006. The 2007 model year’s new intake manifold contributed to the resolution of these issues.
To further reduce friction, Nissan applied a thin layer of coating to key internal components. The QR25’s piston crown has been upgraded, allowing for a higher compression ratio to be used.
Nissan QR25DE Engine Problems
The Nissan QR25DE 2.5L inline-4’s most common issues are as follows:
- Exhaust manifold pre-cat
- Intake manifold screws
- Oil leaks
- Timing chain
The remainder of this article will focus on the problems with the QR25 engine. However, before continuing, there are a few points that must be addressed. This list of issues is what we’d consider to be the most prevalent. It doesn’t necessarily follow that these are typical Nissan QR25DE engine issues. Failures can occur in a variety of ways, but these are the most common.
Having said that, the 2.5-liter inline-4 is quite dependable in general. Nissan was able to fix many of the initial problems with numerous updates and modifications over time.
Despite this, QR25DE engines, even the newest ones, are not without their share of issues. We’ll do everything we can to make sure you know which years and models are the most vulnerable. We’ll come back to this topic at the end of the article and talk about how reliable QR25 is. For the time being, let’s move on to the topics listed above.
1) QR25DE Exhaust Manifold Pre-Cat Material
Okay, let’s get this party started with a fun QR25 engine issue. The 2.5L QR25DE’s exhaust manifold houses a pre-catalytic converter. There’s a third cat in the house. The pre-cat, on the other hand, was designed to be located nearer to the engine.
As a result, the cat warms up more quickly and emits fewer pollutants when started from a cold position. Unfortunately, the QR25 pre-cat material has a history of fracturing and resulting in engine damage when exposed to high temperatures.
Because it’s so close to the engine, some debris could be sucked back into the cylinders as a result of the magnet. The QR25DE may have excessive oil consumption issues if the cylinder walls are damaged by pre-cat material (among other potential issues).
Injecting foreign materials into the cylinders, where they could potentially mix with the oil and coolant, is never a good idea.
In any case, the Nissan QR25 engines from 2002 to 2006 are most affected by this issue. The Nissan Altima and Sentra were the most frequently encountered troubleshooting targets for customers.
Given how long it’s been since most engines had this issue, it’s likely that they’ve been “fixed.” It’s true that Nissan issued a service bulletin, but it wasn’t always a reliable solution. Our main concern is that the QR25DE’s long-term dependability and longevity could be jeopardized if damage occurred in the past.
Nissan 2.5 Pre-Cat Symptoms
The following are signs that your QR25DE 2.5L engine has a pre-cat problem:
- Dirty oil
- Oil consumption
- Low compression
- Engine failure
It’s possible that when the pre-cat fails, you’ll notice dirty oil or foreign matter in the oil when doing oil changes. In the early stages of engine failure, there aren’t many symptoms to worry about. Excessive oil consumption indicates piston rings and cylinder walls have been damaged by the pre-cat material. After that, you may experience compression loss or a QR25 engine failure.
QR25 Inline-4 Pre-Cat Fix / Replacement
Nissan did issue a service bulletin, but it wasn’t a long-term solution. Nissan Neither the pre-cat material nor the pre-cat distance from the engine were altered. That’s why getting rid of OEM QR25DE pre-cat material or a replacement header is your only option (exhaust manifold). For the price of a few extra dollars in extra power, many people choose to use headers instead.
Header upgrades usually cost between $100 and $200, and installing them is simple. It does, however, bring up an additional issue. A heat-damaged QR25 alternator is a real possibility due to the alternator’s proximity to the exhaust manifold. See if you can find an alternator heat shield like this SC Concepts one to help keep it cool and prevent damage to it.
2) Nissan QR25DE Intake Manifold Screw Problems
Another issue affecting QR25DE engines from 2002 to 2006 is an issue with the intake manifold screw. Again, Nissan Altima and Sentra models are most likely to have this problem. Butterfly screws, power valve screws, and so on are all names for the same thing.
A two-stage manifold is used by the engine, with two cylinders in each primary. Four butterfly valves follow (also known as power valves). There are eight butterfly screws in total, two on each valve.
These screws may come loose over time, allowing them to be yanked into the QR25’s 2.5-liter engine. When something like a screw goes through the engine, it’s a bad thing. As the screw exits the engine, it could damage the cylinder head, the walls, or even the pre-catalytic converter.
For 2002-2005 models, the QR25DE butterfly screws were actually redesigned by Nissan in 2006. Nissan issued a service bulletin in response to these issues. By 2021, most of the original QR25 engines should be fixed for the foreseeable future. If you’re still unsure, you should remove the intake manifold and look at the mounting screws.
2.5 Inline-4 Butterfly Screw Symptoms
Because of this, before the screw actually comes loose and goes through the engine, there aren’t any symptoms. QR25 butterfly screw failure symptoms include the following:
- Malfunction indicator lamp (MIL)
- Rough idle
- Power loss
- Engine damage
The butterfly valves and engine air flow can be impacted if the screw loosens. Rough idle and power loss are possible side effects. Hopefully the manifold screw is still in place. Otherwise, it’s critical to make sure the screw didn’t cause any major damage to the QR25 engine while passing through it.
Nissan QR25DE Butterfly Screw Fix
In other words, many 02-05 engines have a long-term fix. In 2006, new screws were used by Nissan to address the problems. To be safe, check your intake manifold again. If there are any loose screws, make sure to tighten them and coat the threads with Loctite. All 8 of the QR25 butterfly screws can be replaced if you obtain new screw designs to use in their place.
3) QR25 2.5L Inline-4 Oil Leaks
Another issue with the Nissan QR25 engine is the occurrence of oil leaks. Older engines are the most likely to have them. To be fair, age and mileage are factors in many cases. Oil leaks are common as vehicles and engines get older. Over time, rubber seals, gaskets, and the like degrade and crack. The valve cover gasket is the major source of QR25DE oil leakage.
There is a gap between the valve cover and cylinder head that needs to be sealed with a valve cover gasket (VCG). This rubber-like gasket degrades over time due to exposure to high temperatures and use. When your car is 8 years old and has traveled more than 100,000 miles, look for any signs of an oil leak from the valve cover.
Other oil leaks on the QR25DE 2.5L I4 engine are possible and have occurred. Make sure that the main seals and the IVTC solenoid don’t have any leaks. There are a few more common ones, but it’s not an exhaustive one.
Nissan 2.5 I4 Oil Leak Symptoms
The signs and symptoms of an oil leak are usually quite straightforward. The QR25DE engine’s oil leak problems can be detected by looking for the following symptoms:
- Visible leak
- Smoke from engine bay
- Burning oil smells
- Low oil
A few visible drops of oil on the ground are a sure sign of an oil leak. The ground may not even be affected by minor oil leaks. The QR25 valve cover gasket is located on the engine’s hood, above the oil pan. Drizzled oil may burn off before reaching the ground if it comes in contact with hot components. The engine compartment may be smokey, or you may detect burning oil smells.
Another possible symptom is low oil, but you should have noticed one of the above ones first. Because all engines use some oil on a regular basis, a low oil level isn’t always a sign of an oil leak.
QR25DE Valve Cover Gasket Replacement
The QR25 2.5L inline-4 engine’s valve cover gaskets are an easy and reasonably priced fix. A low-cost gasket, as is common with oil leaks, is to blame. The VCG is a low-cost, do-it-yourself project for the do-it-yourself crowd. If you take your car to a repair shop, expect to pay anywhere from $100 to $200 more for labor.
If the QR25DE engine has other oil leaks, the repair will be more expensive. Main seal leaks at the front or rear are also inexpensive, but labor costs rise as a result.
4) Nissan QR25DE Timing Chain Problems
The larger Nissan VQ35DE V6 engine has a history of timing chain problems. Timing chain issues aren’t as common with the QR25 engine, but they do happen. Many modern engines use chains instead of timing belts, which saves time and money. Timing chain tensioners, on the other hand, are a problem in chain systems. Tensioners and guides degrade with use.
The QR25DE timing chain may be able to stretch or jump a few teeth as a result of this. It’s an interference engine, which means the pistons and valves travel in the same area. To put it another way, if the piston and valve timing is jumped too far, they may actually collide. That’s not good at all. At the very least, you’ll have a few crooked valves.
The QR25DE timing chain is prone to premature failures and issues. Original engines, on the other hand, may be nearing the point where their components naturally wear out due to their age. If your Nissan 2.5L timing chain has more than 120,000 miles on it, it’s time to have it inspected. Although some cars do reach a lifespan of 200,000 miles or more, it’s better to be safe than sorry.
QR25 Timing Chain Symptoms
Some symptoms of a Nissan QR25DE 2.5L engine timing chain, tensioner or guide problem include:
- Limp mode / power loss
- Poor overall engine operation
The main symptom of a QR25 timing chain failure is rattling or clunking noises coming from the engine compartment. Many people will notice it as one of the first signs. You may also experience MIL, power loss, and poor engine performance in general.
In most cases, however, these signs appear after the chain has broken and a few teeth jumped. In the video below, the VQ35 3.5L V6 sounds like it has a broken chain.
Nissan QR25DE Timing Chain Replacement
If you need to replace the entire chain, tensioners, etc., the cost of labor can quickly mount up. The QR25DE engine is specific to the year and model of Nissan only. Parts cost about $300-600 and labor can easily reach $1,000 or more.
Even though the job isn’t cheap, the alternative of the chain or tensioners breaking is far worse. If the chain gets tangled and some valves get bent, the repair bills can quickly mount up.
QR25 2.5L I4 Reliability
Reliability of the 2.5-liter Nissan QR25DE inline-4 engine Yes, we believe the reliability of this engine ranges from average to above average. Half of the QR25 problems we’ve discussed are confined to the 02-06 model year engines. For a good reason, Nissan has continued to produce the 2.5L engine for the past two decades. They’ve also done a great job with QR25DE updates and upgrades in improving reliability over time.
Early engines, on the other hand, had a slew of issues that could have been disastrous. Engine damage can occur as a result of pre-cats, butterfly screws, or timing chains going bad. For 2007 and later QR25 2.5L engines, Nissan did an excellent job of updating the engine, so these concerns should be minimal.
Maintenance is a big factor in reliability. Use high-quality oils, replace fluids on schedule, and address issues as soon as they arise. If you follow these steps, the QR25DE should perform admirably (with a tiny bit of luck on your side). Over 200,000 miles of trouble-free operation is common for QR25 engines.
Nissan 2.5 CVT Transmission Issues
Another important issue involves Nissan QR25DE powered car CVT transmission problems. Even though the focus of this article has been on engine issues, overall vehicle reliability is a much broader topic than engine issues alone. The CVT automatic transmission on some Nissans has a bad reputation. The CVT transmission on early Altima, Sentra, and other models with the QR25 was covered by an extended warranty for ten years and 120,000 miles.
Transmission problems can occur in any model, even the most recent. This topic has a ton of information, but it’s a little off-topic for this particular article. As a result, that’s where we’ll leave it for now. It’s only worth mentioning because transmission issues can be expensive to fix if discovered after the manufacturer’s warranty has expired.
Which Nissan QR25 2.5L engine do you have and how does it perform? Are you thinking about getting one?
Let us know what you think by leaving a comment below!
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