Hi, so I have a 2017 Infiniti QX60 AWD, it’s basically the same as the pathfinder, same direct injected VQ35DD engine and CVT. You need to look into ‘Walnut Blasting’ the valves to properly clean it, then you install a oil catch can to keep the oily exhaust from getting back into the intake, since the intake needs to come off clean it with purple power and also clean the throttle body, DO NOT touch the throttle body butterfly flap or else you will need to tow the car to Nissan to reprogram the throttle body instead turn the ignition to on without turning the engine on, and press the gas pedal while spraying throttle body cleaner, this will move the butterfly flap. The CVT you need to do an oil change every 30k miles there is 2 filters one for the cvt oil cooler and a strainer filter on the valve body when the cvt pan is removed. Make sure to get new oil cooler housing gasket and oil pan gaskets. My CVT oil came out completely black, it’s supposed to be clear/light blue. Make sure not to overfill the CVT, level it by warming up to 107 F, open overflow plug, wait for oil to come to a slow trickle and close it back. I bought the car new with 6 miles and now at 103k mile, thing still runs buttery smooth.

 

Yep what I was getting at earlier in this thread ( a year or more ago), was the only way to really clean the intake valves is by some mechanical method like the walnut shell blasting like you suggested. Sprays won't do it. I'm not sold on catch cans either. Could they help some? Maybe. Combustion vapors are still going to pass straight through a catch can.

I'm with you on the CVT spill and fills. I've done at least 4 of them on my 2019 at this point. First one was right after I bought it used in Oct 2019 w/ 24K miles on it as an ex-rental. The CVT fluid was very dark. I haven't touched the side mounted cartridge filter yet, nor the pan screen. Not sure I'm going to.

Equally as important as the CVT juice spill/fills is changing the gear oil in the transfer case. If you haven't done that yet in your 2017 QX60, you are beyond needing to. They only hold a few ounces of gear oil and it will be black, glittery and beat to heck.

 

I've done a bit more investigation. It appears that if this is to be attempted, the cleaning solution should contain polyetheramine aka PEA which is active ingredient of Techron.

The CRC gdi cleaning product is supposed to contain PEA.

I don't believe Seafoam uses PEA as active ingredient.

I will see if the gdi service at jiffy lube uses PEA. When they did this service on my vehicle, they appeared to have a can of cleaning solution with compressed air connection and I assume they connected thru this PCV valve hose.

I'll also ask my service advisor at Nissan to see if they can be more specific about their service.

There are also newer oils in the market specifically for gdi engines like Valvoline Modern Engine Oil with low NOACK values.

Valvoline also markets gdi cleaning services thru NTB with their solvent that I assume contains PEA.

For now I'll just keep changing the oil at 4000 mile intervals.

 

For now I'll just keep changing the oil at 4000 mile intervals.

When I changed the engine oil on my 2019 yesterday, the oil/filter had 3500 miles on it, yet still came out dirty diesel engine black. It freaks me out every time. Never saw anything like it unless the oil had some crazy amount of miles on it. I couldn't bring myself to go beyond 4000 max on these DI PFs. Been doing oil changes since I was like 13-14yrs old. I'll be fiddy in a few months. LOL. There has got to be sludged up 2017+ out there if folks neglect OCs.

 

While doing an oil change on my 2019 today, I pulled off the plastic engine cover as I normally do to give everything a look over. Looks like the PCV valve is right up front on the cam cover near the oil fill port. The hose to the PCV valve would be an ideal access for intake cleaning sprays or solution. Loosen the hose from the PCV valve, start the engine, pop the hose off and have at it with the spray. May need someone to sit behind the wheel to keep the RPMs up though.

 

I've used Quaker state, Pennzoil, and this last change was valvoline. Previous oil test data I got back didn't show much that was concerning, I'll send this last one (Valvoline)to be tested and let folks know what they say. I don't expect it to show any effect from doing this treatment.

I did go with Mobile 1 this time and an O'Reilly house oil filter,vwhere before I was using higher cost filters. Just don't seem to make sense spending on better filter since replacing oil and filter at 4k miles.

This vehicle has mostly highway miles so my usage probably as benign as possible. I was gonna start towing though...

 

Seems like there is no reliable info regarding this issue for any DI engine that I have found besides YouTube videos that show improvement with boroscope camera. Of course CRC and seafoam claim good results with no side effects.

I was not able to see what the jiffy lube guy did, but the idle was very smooth after he was done.

The sea foam can went in the intake after the maf sensor with the engine revved around 2000 rpm. Hard to see anything since the tube not visible in front of the intake valve. Instructions are to shut down the engine and let soak for 10 min and then drive hard for several miles.

The jiffy lube guy did not ask me to do anything after the treatment.

I can't say that it is running any smoother after the sea foam but it was very smooth already. But it did put on a good "smoke show" as I have seen it referred to.

Kinda wish they had left the engine lower powered with conventional port fuel injection so this isn't something new to deal with.

 

Kinda wish they had left the engine lower powered with conventional port fuel injection so this isn't something new to deal with.

Right? Our last Nissan was a 2016 Nissan Quest that basically has the same engine and CVT as the PF. It was the VQ35DE (port injected). I had better power, better fuel economy and was quieter. The power thing could have been due to a different final drive ratio though, I dunno.

I think the best thing we can do for our 2017+ direct injected PFs, is use a decent quality synthetic oil, preferably one with very low NOACK and don't extend oil change intervals beyond ~4K miles or so until we get some long term data on carbon build-up on.

The problem with those spray cleaners is, you're supposed to inject them in a large vaccum line closest to the valves. Supposedly if you inject it upstream of the throttle plate like is sounds like you did, they are not as effective (I'm told).

 

I'm assuming Iffy Loob used a spray can product? Where did they inject it? What did they use?

Where did you inject the seafoam?

I don't have a concern with my 2019 yet that was also purchased last year as an ex-rental with 24K miles on it. We've only got 35K on it at this point but I've posted about my DI intake valve build-up concerns in the past and no one had experienced it yet.

Thing is, using using liquid products through a vacuum line isn't going to remove heavy build up and will throw a bunch of junk in your catalytic converters. My theory there is this will shorten the life of the cats. In essence your possibly making one thing marginally better, while taking life away from something else.