K&N air filter for Duramax Diesel- Yes or No

I have an 03 Duramax and I run the standard filter.  The K&Ns let too much air and particles through for normal driving.  If you are drag racing and trying to squeek every last bit of HP out of your truck, then K&N might be ok.  The HP gains are actually negligable on daily driving applications.

The most important filters on the truck are your fuel filters and water separators.  Make sure those are new and change them on schedule.  I run extra filtration from a company called FASS.   https://www.youtube.com/watch?v=NqfE1eqfTwU

https://amzn.to/3IwKl76

@Eric Dye posted:

I have an 03 Duramax and I run the standard filter.  The K&Ns let too much air and particles through for normal driving.  If you are drag racing and trying to squeek every last bit of HP out of your truck, then K&N might be ok.  The HP gains are actually negligable on daily driving applications.

The most important filters on the truck are your fuel filters and water separators.  Make sure those are new and change them on schedule.  I run extra filtration from a company called FASS.   https://www.youtube.com/watch?v=NqfE1eqfTwU

https://amzn.to/3IwKl76

Thanks.

From what I am reading, its mainly an issue with 2020 and newer Duramax’s.

I am taking my truck in for an oil change this week and wanted to change the engine and cabin filter first. The last time I took it in the dealer wanted $150 for both air filters on my gasser. Thats getting a little pricey for my taste.

I’ve used K&N filters back in the 1980’s/1990’s in Jeeps.  I learned they are less restrictive than paper filters,  and they filter best the dirtier they get. Using them I could never really detect any performance gains. I stopped using them after I noticed a fine film of dirt in the throat of several of the various Jeep carburetors, which was an indication that they were not functioning well to prevent dirt from entering the engine.

Based on my experience I would recommend against using K&N filters. A OEM filter or a quality aftermarket paper filter will likely provide the best protection for an expensive diesel engine.

I use to use K&N’s on my dirt bikes but started using UNI filter after too many rebuilds. I thought having one on my TV would be safe, but after seeing how dirty my throttle body got I switched back to paper. If you can shine a light through it, it’s a no go.

I've used K&N filters in past, my new truck has paper filter.

With all the sensors, oil contamination, from wet filter, can cost $$$.

Changing filters yourself, will save at least half.  If you drive many dirt or gravel roads, change filter more often.

I had a 2004 Duramax.  K&N air filter, with a oil spray on it.  Dealer told me the oil gave the air filter sensor problems.  As soon as I mentioned K&N air filter, both tech's rolled their eyes.  Now I just buy a quality filter.

Stay with a good quality paper or  OEM filter. As Robert said, it’s easy to change yourself and about half the cost of shop installed. The big thing with a diesel truck is oil and fuel filters. I stay with the 5000 mile interval. My last Powerstroke I drove 360,000 miles with that maintenance schedule. No major engine failures.

Bob/Texas

@Eric Dye posted:

I have an 03 Duramax and I run the standard filter.  The K&Ns let too much air and particles through for normal driving.  If you are drag racing and trying to squeek every last bit of HP out of your truck, then K&N might be ok.  The HP gains are actually negligable on daily driving applications.

The most important filters on the truck are your fuel filters and water separators.  Make sure those are new and change them on schedule.  I run extra filtration from a company called FASS.   https://www.youtube.com/watch?v=NqfE1eqfTwU

https://amzn.to/3IwKl76

Until recently, the Duramax trucks did not put a lift pump in the fuel tank.  The last few years, the GM trucks now have one.  The FASS system, in addition to the two extra fuel filters, also included a lift pump at the tank.  IMHO, this is important, as it eliminates the need for the CP3/CP4 injector pumps to pull fuel from a fuel tank.

As Eric mentions above, stopping water from reaching the pump/injectors is also very important.  The current FASS water filter actually stops water from going forward to the stock filter and injector pump.  So, I added one to my truck.

Diesel mechanics constantly state, keeping fuel and air clean is extremely important in modern diesel trucks.  In commenting about the OP question, I throw my hat in with the above responses.  The stock air filter on your PU is an abundant filter.  Just change it often.  It is very easy to change, so you don't need to pay for someone else to do it.

One final comment.  Since the current Ultra low sulfur fuel has less lubrication than regular No 2 fuel, I now add an fuel additive to be safe (Hot Shot).

Congrats on your new truck, Jason!   

@Les1 posted:

Until recently, the Duramax trucks did not put a lift pump in the fuel tank.  The last few years, the GM trucks now have one.  The FASS system, in addition to the two extra fuel filters, also included a lift pump at the tank.  IMHO, this is important, as it eliminates the need for the CP3/CP4 injector pumps to pull fuel from a fuel tank.

As Eric mentions above, stopping water from reaching the pump/injectors is also very important.  The current FASS water filter actually stops water from going forward to the stock filter and injector pump.  So, I added one to my truck.

Diesel mechanics constantly state, keeping fuel and air clean is extremely important in modern diesel trucks.  In commenting about the OP question, I throw my hat in with the above responses.  The stock air filter on your PU is an abundant filter.  Just change it often.  It is very easy to change, so you don't need to pay for someone else to do it.

One final comment.  Since the current Ultra low sulfur fuel has less lubrication than regular No 2 fuel, I now add an fuel additive to be safe (Hot Shot).

Congrats on your new truck, Jason!   

Thanks for all the good info. I will stay with the OEM filter.

I assume the dealer will check the water separator, and change if necessary when I get the oil changed? Like I previously stated first time diesel owner. I had a diesel tractor and it had a visible water separator that I could empty when full, not sure on this truck.

Jason,

The stock fuel filter on your new PU, has an electronic sensor on the bottom so it is supposed to send a message to your dash if water is present.  It also has a drain valve, so one can manually remove water collected in the filter.  

All diesel today, likely has some water present, and the stock fuel filter can protect your expensive fuel delivery components from small amounts of water.

The real danger is when someone gets bad fuel contaminated with lots of water.  Then the stock filter can allow the water to go through to the injector pump.  This can cause catastrophic damage to the pump/injectors, etc.  Repair costs can exceed $10,000!  

The Bosh CP4 pump can also be damaged by diesel fuel with low lubricity.  Chances are relatively low, you will have any of these problems.  😊

@Jason & Celia-Texas posted:

Thanks for all the good info. I will stay with the OEM filter.

I assume the dealer will check the water separator, and change if necessary when I get the oil changed? Like I previously stated first time diesel owner. I had a diesel tractor and it had a visible water separator that I could empty when full, not sure on this truck.

Les,

Are you using Hot Shot (EDT) Everyday use?

@Jason & Celia-Texas posted:

Thanks for all the good info. I will stay with the OEM filter.

I assume the dealer will check the water separator, and change if necessary when I get the oil changed? Like I previously stated first time diesel owner. I had a diesel tractor and it had a visible water separator that I could empty when full, not sure on this truck.

I would never assume the dealer would do anything in your best interest.  I would suggest learning to change and service the fuel and water filters yourself.  Or find someone you trust.  In my experience, the dealer can't be trusted.

Jason,

The fuel filter on your new truck is much easier to replace, than previous models.  It is SO EASY.  As easy, (perhaps easier than the oil filter) ! 

Here is a video showing how:

https://www.youtube.com/watch?v=-AN5h3_cysk

During our cold months, I use Hot Shot's EDT Winter Defense.

https://www.hotshotsecret.com/...pEAAYASAAEgLyQfD_BwE

Now that our temps have warmed up, I have started using their LX4.  I believe it has the most lubrication than any other additive.  It was developed specifically to protect the Bosh CP4 injector pumps.  Does it prohibit the pump from blowing up?  I honestly don't know, but Lubricity is my main concern about todays diesel fuel.

https://www.hotshotsecret.com/...yEAAYAiAAEgJYS_D_BwE

Again, I agree with Eric's statement, regarding most, (but not all) dealers.

You have a beautiful truck!