M56 Carbon Build Up

[ken in az]

Hi All, just figured I'd share my 115k Mile intake valves.

According to the Service History it is had the Intake Valve cleaning procedure done every 30K miles since before I got it. I literally just did a Dual can (one per throttle body) SeaFoam Treatment and this is what they look like...





I'll be taking pictures and posting a how to for cleaning them.

[madmanpauly]

Yeah, that's the problem with direct injection. Many articles have been written about it. Using sea foam won't help because sea foam runs through the injection system which is injected directly to the combustion chamber and won't clean the top of the valves as conventional injection systems would.

Are you using a particular product to clean it?

[ken in az]

No, I injected the aerosol version of SeaFoam directly into the intake before the throttle bodies and after the mass air sensor.

I did 2 cans since we have dual throttles.

[EdBwoy]

Oof! And that's the after picture? How was the before state?

[ken in az]

I didn't get a before image unfortunately. I didn't get my Borescope in time to do a before image.

Honestly I was hoping it would be better, but I have also seen a lot worse.

[hemachayart]

Spray, Ethylene Glycol into port in this picture. It will be white smoke come out after start but it's ok.

[Ilya]

Spray, Ethylene Glycol into port in this picture. It will be white smoke come out after start but it's ok.

Can you buy that?

OP, how long did you let the car sit with Seafoam soaking? I usually do a ton of it and let it sit for like 45-60 minutes even though most guides say 30.

[hemachayart]

There are plenty one of them
https://www.carolina.com/specialty-chem ... /861710.pr

[ken in az]

Here are my updated Before pics - these were the worst of the bunch. You can see how the carbon is literally piling up on the valves and ports blocking flow.









I used a combination of CRC Intake Cleaner, SeaFoam Aerosol, Brake Cleaner, Toothbrush with trimmed bristles, and a sharp pick.

Let me tell you it was a pain in the neck. I wish I would have done the walnut blasting, but with how slow everything is taking to get delivered these days I decided to just go with the chemicals.

Driving impressions after cleaning, no they aren't spotless and shiny like the walnut lasted intakes, but they are clear from obstruction 98%. First day driving it was still smoking when I lid into the throttle at low RPMs. Burning off the residue of the cleaner and the extra carbon is what I am assuming it was. took a day and a half to stop letting out little white puffs of smoke here and there.

After the smoke cleared, WOW - it drives sooo much better. I notice it most in low throttle to part throttle. No more hesitation, no more hunting for the right gear to be in when going slow. It's like the car woke up from hibernation and is ready to go.

Well worth the time and effort. FYI - it only took me 45min to get the intake manifold off. It's easy enough I'll probably do the walnut shells here in a month or two LOL.

Let me know if you have any questions.

[DFW2011M56S]

I did my carbon clean and noticed the same thing. I walnut shell blasted. Makes a massive mess of the engine compartment. Little blobs of gummy carbon and walnut shells everywhere.

Mine was actually setting a P0300 code at the time.

[Yoda's Master]

Request diy when you walnut blast

[Ilya]

Yes, please do a DIY.

[DFW2011M56S]

I did the walnut shell blast after loosening the deposits with a good soaking of B12. Finished the job with one of those metal dentist picks to remove the ring of gummy carbon left behind on the valve seats.

I had previously used two different chemical cleaners. The chemicals failed to reach the front 4 cylinders because the PCV ports for those cylinders were plugged with gunk in the manifold. I cleaned the manifold and got all 8 pcv ports flowing properly again. Car ran like new after. Even with 90+K mile plugs.

I used GM top engine clean through a vacuum powered dripper every 5K right before changing the oil after that. Half the can into the PCV valve hose on each bank. When I pulled the intake to change my starter solenoid at ~115K they were still virtually spotless. I think the Mobil One I was running helped alot as well as it does not sludge the valves as badly because it is more resistant to coking with high heat. Previous owner was running dinosaur oil in it. I think a few more treatments would have gotten the valves clean on the rear 4 cylinders. It cleaned the heck out of the ports. The residual just ended up gunked up on top of the valves. If it had been done regularly from low mileage through the PCV ports the passageways on the front cylinders never would have clogged up either. If you look at the intake manifold you will notice both sides have a rail that looks similar to a fuel rail. Each rail has a hole drilled through it or cast through it into the manifold runner for each cylinder to evenly distribute the PCV gasses. CRC makes a cleaner that works very well that comes in an aresol can. I think a can into each bank every 200 miles or so would probably clean up most if not all of this over several treatments but it would be a crap shoot without pulling the manifold to see what is happening.

[ken in az]

I'm going to try the commercial version of the BG Platinum Air Intake, Valve Cleaner - https://www.bgprod.com/catalog/gasoline ... r-cleaner/

Here's a video of it in action by The Car Wizard on Youtube. He uses it on an Audi/Lambo V10. - https://youtu.be/8zmXyB38mRg

Using the PCV hoses on the intake behind the Throttle Body is a great idea. That hose connects to each individual Intake port so the cleaning solution should get to all the valves - here, check out this video, please don't mind my heavy breathing as my allergies have almost turned me into a mouth breather LOL

https://i.imgur.com/0tKxMXt.mp4

I imagine solution being pulled in and distributed evenly, like little injectors for each cylinder's valves.

[Oleg92]

I dont have that much expertise like you guys do?

I am at 70k and never done it.

Looks concerning. how much would that cost at a regular shop to do ?

[Malbec 56 Beast]

BG44k is awesome stuff
Oil changes fuel and opening it up can help keep this buildup down. 3M makes a great fuel additive that works great

Andy

[DFW2011M56S]

BG44k is awesome stuff
Oil changes fuel and opening it up can help keep this buildup down. 3M makes a great fuel additive that works great

Andy

Fuel additives or top tier fuel will not help a bit for this problem. Fuel does not flow over the valves or through the ports.

[AZhitman]

^ Correct. These are direct injection engines.

We had the same issue on my wife's '13 Mazdaspeed 3. We did the walnut shell blasting.

[DFW2011M56S]

^ Correct. These are direct injection engines.

We had the same issue on my wife's '13 Mazdaspeed 3. We did the walnut shell blasting.

Yea direct injection sucks for carbon buildup. Even my stock port injected 3.5HR was far from clean at 178K miles when I did the plugs. I had to do the valve covers today at ~216K. I have been running revised cam timing maps with much less cam overlap than stock for about 5,000 miles in that car with the free flowing exhaust. I have used Techron a few times this year which actually gets to the ports and valves. On that port fuel injected engine this was what greeted me today.

Also 60K worth of synthetic oil changes with a Mobil One filter every 6K have the 3.5 spotless inside. I highly recomeend Mobil One, Penzoil Platinum or Amsoil for these high reving, high horsepower, massive heat building cars.

M35H and M37 guys can use Techron or top tier fuels like Shell or Chevron premium and get a valve cleaning benifit from them.

[AZhitman]

Right - But as you stated earlier, additives or fuel will not help a bit for this problem. Let's be sure not to confuse those who don't understand the difference.

Motor looks squeaky clean!

[DFW2011M56S]

Right - But as you stated earlier, additives or fuel will not help a bit for this problem. Let's be sure not to confuse those who don't understand the difference.

Motor looks squeaky clean!

I get you.

Thats why I specifically said M35H and M37 owners not M56 owners. Don't want those guys thinking their valves will look the same way as the 5.6VD direct injected engine.

[Shanehsmp]

Bringing this back from the dead - Ken, did you replace your intake manifold gaskets or did you re-use them? I can't locate them or a proper part number anywhere.

[ken in az]

I just reused them

[VStar650CL]

Spray, Ethylene Glycol into port in this picture. It will be white smoke come out after start but it's ok.

Since it's resurrected, I'll put my two cents in. Glycol works great, but it has a surprisingly low flashpoint (actually lowest on the whole car). It can flash in your intake and make a mess. The best, safest stuff for decarboning is a teaspoon of ATF (any kind works). Feed it down any vacuum port, with the engine fully warm and revved about halfway to redline by an assistant. The vapor films on the surface of the carbon and the sudden temperature differential blows it apart. Squeaky clean in 5 seconds flat, no risk of flashback, and unless you're running cat-less, no cloud to annoy the neighbors.

[C6Joe1957]

Bringing this back from the dead - Ken, did you replace your intake manifold gaskets or did you re-use them? I can't locate them or a proper part number anywhere.

I bought these awhile back when I was trouble shooting my P0087, P0300 and P0304 trouble codes. post6814737.html?sid=36cf7a6a0fe8993ee3 ... 4#p6814737



You can get them here: https://www.infinitipartsdeal.com/parts ... &filter=()

Or on Amazon: https://www.amazon.com/Infiniti-A4035-1 ... B00L2O0K0S

[Ilya]

Spray, Ethylene Glycol into port in this picture. It will be white smoke come out after start but it's ok.

Since it's resurrected, I'll put my two cents in. Glycol works great, but it has a surprisingly low flashpoint (actually lowest on the whole car). It can flash in your intake and make a mess. The best, safest stuff for decarboning is a teaspoon of ATF (any kind works). Feed it down any vacuum port, with the engine fully warm and revved about halfway to redline by an assistant. The vapor films on the surface of the carbon and the sudden temperature differential blows it apart. Squeaky clean in 5 seconds flat, no risk of flashback, and unless you're running cat-less, no cloud to annoy the neighbors.

So, same application method as Seafoam. I'm inclined to try this...lol. Way easier than all of this stuff...

[VStar650CL]

So, same application method as Seafoam. I'm inclined to try this...lol. Way easier than all of this stuff...

Learned it from a clever Italian boss running the gas station where I got my first wrenching job. Back in bad old prehistory, small block Chevys with grandma drivers could build up carbon 1/2" thick on the backs of the intake valves. They'd come in with a miss that would show up as poor compression. Pre-catalysts, you could stand behind the car and watch quarter-sized chunks of carbon fly out the tailpipe when the ATF went in. Customers who chose to watch would often blanch, like, "Did that really come out of my engine?"

[C6Joe1957]

Spray, Ethylene Glycol into port in this picture. It will be white smoke come out after start but it's ok.

Since it's resurrected, I'll put my two cents in. The best, safest stuff for decarboning is a teaspoon of ATF (any kind works). Feed it down any vacuum port, with the engine fully warm and revved about halfway to redline by an assistant. The vapor films on the surface of the carbon and the sudden temperature differential blows it apart. Squeaky clean in 5 seconds flat, no risk of flashback, and unless you're running cat-less, no cloud to annoy the neighbors.

Oh man I love this stuff! I'm going to perform this procedure this weekend or sooner.

[C6Joe1957]

Would the cats be stressed in any way?

[VStar650CL]

While I'm in here, let me tell the war story about how I discovered glycol's flash point, it's funny. Some years back an Altima rolled into the dealership on a hook with the engine hood burnt to a crisp. The story was, it caught fire in a restaurant parking lot while the family was eating breakfast. After looking it over carefully, the location and spread of the fire seemed to indicate it started in the fat harness atop the engine, which on an Altie contains the alternator cable and a bunch of skinny ground wires. The heat shield was missing from the cat, and I figured they baked the insulation until something failed. It made sense, a short to one of those skinny grounds would flame up long before the 100A alternator link failed.

We had a DTS at the time who happened to be an engineer who tired of his desk and decided to hit the field. Japanese gentleman with a mind like a samurai bear-trap, he was just plain brilliant. Probably forgot more about automotive chemistry than some other engineers will ever know. I asked for his opinion when he visited. He pointed straight at the missing heat shield, and I thought, "Ahah, I got this right." But when I voiced it, he shook his head and patiently explained that the heat shield wasn't only to protect the car from the cat, it was also to protect the cat from the rest of the car. He educated me about glycol's flash point and opined that I would probably find a pinhole in the radiator.

Not quite ready to buy it, after he left I prepared to yank the radiator and run a pressure test. Turned out I didn't need to. When the radiator moved, I found a 6-penny brad nail stuck through the condenser fins and right into a radiator tube, no more than 3" sideways from the center of the converter. When the family parked at the restaurant, the cooking engine turned the glycol into fumes. It hit stoichiometry underneath the closed engine hood and went up like a candle from the converter's residual heat.

I guess there's a broader lesson in there about heat shields being in place for a reason, but damn... whoda thunk anti freeze could be that dangerous?