[BMWinAZ]

Quick question. My car is at the dealer for some CPO work and they tried to sell me their Engine Decarbonization" and „Fuel Injector Flush" for $200 a piece. This is a N55 engine with 35k miles. I know these procedures are pretty unnecessary for a well maintained N52 engine. Are they more useful for the direct injected N55?

[sspade]

Fuel injector flush is likely hogwash so long as you've been using a top tier fuel of 91 or better octane. I also use a can of Techron every 10k just to be sure and that may even be throwing money down the drain.

Now the Engine Decarb... I would be interested to hear more about. Wonder what exactly is included in this service?

[Billfitz]

They're probably using this or something similar for 'de-carbonization':
https://www.amazon.com/CRC-05319-Int...e%2C223&sr=1-1

The other option is walnut blasting, which would cost a lot more than $200. Cleaning the intake valves yearly is a good idea, especially as you can do it yourself for less than $20. Fuel doesn't go through intake valves with direct injection, so detergent in the fuel won't clean them. While you're at it clean the MAF sensor:
https://www.amazon.com/CRC-05110-Mas...GCNCBESQ5JPAEP
The injector cleaning is probably using this:
https://www.amazon.com/dp/B07576419V...d-dda674112141

I put that in my tank yearly. It can't hurt, beats replacing injectors.

[_bdiddyb_]

SCAM! don't fall for that! Unless they "walnut blast" your intake, and you can do the injector flush yourself. 35K is too soon for de-carbonizing anyway.

[Billfitz]

Originally Posted by _bdiddyb_

35K is too soon for de-carbonizing anyway.

It's too soon to justify the expense of walnut blasting, which requires removing the intake manifold and a lot more. But if you clean the valves regularly you may never need walnut blasting. An ounce of prevention...

[sspade]

Do we think that using quality fuel and the odd bottle of Techron will keep injectors clean, long term?

[bavarianride]

Originally Posted by Billfitz

It's too soon to justify the expense of walnut blasting, which requires removing the intake manifold and a lot more. But if you clean the valves regularly you may never need walnut blasting. An ounce of prevention...

My N26 gets 2 bottles of Costco fuel injector techron cleaner very 5k-6k miles. That should address the injectors, but not intake valves though.

So should walnut blasting still be considered@50k-60k miles?

[Billfitz]

How long do you plan on keeping the car? It might be a worthwhile investment if that's another 30k miles or more, especially if you do it yourself. The blasting part is easy, removing the intake manifold and all the stuff it takes to get at the manifold is the hard part.

[bavarianride]

Originally Posted by Billfitz

How long do you plan on keeping the car? It might be a worthwhile investment if that's another 30k miles or more, especially if you do it yourself. The blasting part is easy, removing the intake manifold and all the stuff it takes to get at the manifold is the hard part.

Local indies charge $600+ for that job, and yes, it is not designed to be easily serviceable,, plus the risk of breaking stuff(even done by paid pros).

My thinking is to keep for another 40k to 50k, so dont-touch for now.

[Billfitz]

I don't know if it's possible to get a look at the valves with a borescope without too much hassle, but if it is I'd consider doing that before spending $600 on something you don't need, or not spending $600 on something you do need.

[bavarianride]

Originally Posted by Billfitz

I don't know if it's possible to get a look at the valves with a borescope without too much hassle, but if it is I'd consider doing that before spending $600 on something you don't need, or not spending $600 on something you do need.

That sounds like a good idea, although borescope through spark plug openings only get to combustion chamber, so the backside of intake valves are still blocked, correct?

BTW an indy tried in vain to use borescope through the oil cap opening to inspect the plastic TC rail guards, as there were too many twists and turns along the way.

[Billfitz]

You wouldn't go through the plug holes, you've got to go through the intake manifold. I don't know if that could be done easily.

[bavarianride]

Originally Posted by Billfitz

You wouldn't go through the plug holes, you've got to go through the intake manifold. I don't know if that could be done easily.

Got it, but getting through intake manifold(and removing all those components) probably will be 2/3 the work of walnut blasting, right?

[IraHayes]

Originally Posted by sspade

Do we think that using quality fuel and the odd bottle of Techron will keep injectors clean, long term?

Injectors, and piston tops too. Techron is probably one of the few additives out there that I would say is legit, and not snake oil.

[BMWinAZ]

Originally Posted by _bdiddyb_

SCAM! don't fall for that! Unless they "walnut blast" your intake, and you can do the injector flush yourself. 35K is too soon for de-carbonizing anyway.

Didn't get it done at the dealer. But I started to think about researching additives/cleaners by Techron and LiquiMoly. May use them on all my cars in the future.

[Billfitz]

Originally Posted by bavarianride

Got it, but getting through intake manifold(and removing all those components) probably will be 2/3 the work of walnut blasting, right?

I don't know, haven't looked at it all that closely. You might get in by just pulling the pipe at the throttle body entrance.

[J.D.]

Originally Posted by Billfitz

It's too soon to justify the expense of walnut blasting, which requires removing the intake manifold and a lot more. But if you clean the valves regularly you may never need walnut blasting. An ounce of prevention...

How do you clean the valves without walnut blasting?

[Billfitz]

Read post #3.

[J.D.]

Originally Posted by Billfitz

Read post #3.

Oh ok, I've read differing opinions as to whether that stuff works or not...

[bavarianride]

Originally Posted by J.D.

Oh ok, I've read differing opinions as to whether that stuff works or not...

Techron cleaner works to some extent, but only on surface that are touched by the fuel. With direct injection, the back side of intake valves cannot be cleaned by techron fuel additives.

[Billfitz]

Originally Posted by J.D.

I've read differing opinions as to whether that stuff works or not...

Opinions are like rectums: everyone has one, and they're only good for crap. Film don't lie. There are youtube videos that show its effect.

[J.D.]

Originally Posted by Billfitz

Opinions are like rectums: everyone has one, and they're only good for crap. Film don't lie. There are youtube videos that show its effect.

Duly noted. Thanks.