L5P Duramax Problems [How Long will it Last?]

Now, we have the cream of the crop – the LSP. This is an engine that is found on the current models of the Chevy Silverado and the GMC Sierra. This one has been around for half a decade now. Many consider it to be GM’s best masterpiece of engineering as a result of its post-emissions nature of it. that being said, there are some L5P Duramax common problems:

The truck’s MAP sensor can get clogged up with soot particles and the connector(s) for the fuel injector(s) can also malfunction. Apart from these issues, tuners do face gearbox problems when they modify their truck.

That being said, let’s look at some common L5P issues:

Some L5P Duramax common problems you should know about,Below are some things to look for if you’re searching for an L5P Duramax for sale:

 MAP sensor failure

The most common problem with this engine is the failure of the Manifold Absolute Pressure (MAP) sensor. As with other diesel engines, this sensor is prone to becoming clogged. This is because of the particles of soot that tend to build up in the sensor. The pressure detected will hence decrease.

As a result, the sensor is no longer able to give the correct readings for the values of air pressure. This screws up the engine’s data and it is no longer able to perform like it should. The efficiency of the engine gets ruined and later on, the engine can fail as well. This is preceded by misfires and roughness.

 Bad injectors

Some L5P Duramax owners have complained about receiving P0204 or P0300 error codes. This translates to a problem with the connectors on the fuel injection system. The most common culprit in this case is connector #4 (aka the one for the 4th fuel injector).

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Because a vehicle cannot run without its fuel injection system, you can expect not only a drop in its performance. But you can also expect misfires and the engine performing rougher when idle. It can go as far as to put the truck’s engine into limp mode. Yes, the engine won’t exactly fail though.

 Transmission issues

One of the reasons that people like Duramax diesels so much is because you can modify them to increase their power outputs. You can add a couple of hundred hp to the mix which can totally change the feel of the engine. However, in the case of the L5P Duramax, the gearbox won’t be able to handle it.

The transmission will be ruined if it won’t be able to take care of those extra horses. This is why you need to mod it as well if you’ve decided to tune up the engine. You’ll need to make all sorts of upgrades to the gearbox in that case; if you want reliability from it.

Cylinder issues

The L5P Duramax misfire issue is a common one and you can expect a number of causes for it. Take a look at this document for example, by the NHTSA. It talks about a lack of high performance and engine misfires for the GM full-size trucks with the L5P.

The major reason stated for it is a problem with the cylinder. For example, the intake/exhaust pushrod may have broken. Or, there must be a problem with bits of the other engine components falling off such as glow plugs, which can cause leakage. Another probable cause is the excessive valve clearance on it.

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 Miscellaneous problems

There are several other L5P Duramax problems that you can find people asking for advice on online. You’ll also notice that most of them are for the truck’s emissions system. The DEF setups have been considered to reduce the reliability which is also an issue with the older Duramax models.

The DEF tank heater can fail like in the older LML Duramax. You can also face problems from the catalytic convertor system. Other than that, there can be a loss of coolant which can cause the engine to overheat. It is due to the truck’s coolant reservoir which will need a replacement due to excess damage.

Is the L5P Duramax a good engine?

Yes, it is a fantastic engine that may be one of the best takes on what a modern diesel should be. There’s an ample amount of power available, which has a positive effect on the truck’s towing capacity. You can expect this motor to handle a lot more power – up to 800 hp without any deletes.

They’ve also fixed most of the problems from the older Duramax engines. This means that this motor is a lot more reliable, despite being from an era of emissions. You won’t need to go out of the way in order to replace the original parts with aftermarket ones.

But what about the problems that have been mentioned above? You’ll just need to care for the common issues like the MAP sensor by keeping it squeaky clean from soot.

Is the L5P reliable?

As mentioned above, they’ve fixed a host of issues that bothered Duramax owners in the past. The new designs and components for the camshaft, turbo, fuel pump and injectors, and the tranny upgrades definitely help its cause.

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As a result, many of the overheating issues have been fixed. Still, this engine has been vulnerable to recalls; one of them fixed its block heater problem. There was another recall for the Diesel Particulate Filter (DPF) as well. These recalls have happened for more than one L5P Duramax year.

How long will an L5P Duramax last?

You cannot really get the value out of such a masterpiece of an engine without putting a couple of hundreds of thousands of miles on it.

VEHQ expects the L5P to e able to cross 500k miles without any major repairs for it.

Of course, Duramax owners may be aiming for 300k miles without any overhauls. These numbers can easily come true if the truck’s owner keeps it well-maintained. Regular tune-ups and periodic cleaning can positively cause the truck to drive around for decades.

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