Cleaning carbon buildup off intake valves and pistons

[Ian Swett]

I have some pretty serious carbon buildup on my 2000 Passat 1.8T on the intake valves and the piston. The intake valves look pretty much identical to the dirty valves in the chevron techron ads, and I can't see any piston rings on the top of the pistons. I actually took my intake manifold off and tried to remove some of the carbon off the valves, but it didn't work very well. I got some off, but they certainly weren't clean afterwards. They just had less carbon mass on them.

I only have 25k on the car, so I'm bit concerned about whether this is a symptom of a larger problem or a cause, but the car isn't running quite like new, so I think its worth cleaning out and seeing if it comes back.

I've done a motorvac cleaning and tried BG44k, both of which might have helped some, but not significantly. I'm trying some Amsoil PI right now, but I doubt that'll end up working much better than either of the other two.

So what are my best options? I've heard GM Top Cleaner, SeaFoam and just plain water all will clean things out, but have to be sucked up into the intake.

I considered trying lube control as a top cleaner, but I don't know how it compares to the other options. I've also considered buying some fuel power, but since it seems like I have some nasty deposits, I'm not sure that would be strong enough to do anything in a reasonable time period.

-Ian

 

[Gary Allan]

I've always used AFT. It leaves no residue and combusts cleanly (well ..it does produce a tremendous cloud). This has gone out of vogue in the past 25-30 years since FI has been widely adopted. Most car engines don't need such treatment for most of their first owners life (second owner even). The problem is that typically we no longer have a central manifold port with which to introduce the cleaning agent (I usually use the PCV line). With the adoption of the metered orfice ..the volume of blowby intake has been radically reduced ..at least below the throttle plate (the remainder gets shunted to above the throttle plate) and, in the case of my 3.0 Mitsubishi and my 4.0 Jeep, only sees one intake runner. This now tends to require you to pour the agent into the throttle body (a bit difficult with a horizontal TB like my 3.0).

Water works as well ..but it frustrates the combustion process and requires more tap dancing by the operator. Atf is typically transparent ..except for the plume out the tail pipe.

Idealy I would think that rigging a washer nozzle to a washer pump (using water) and turning it on at highway speeds would do the job nicely. This is usually beyond what most want to do to get this treatment done. I bought about 8 ft. of PCV hose and ran it in the drivers compartment and would shove the hose into the AFT at highway speeds. I naturally did this at night with no traffic. For those who think that this is environmentally negligent I would assert that I probably reduced emission in the treated vehicle for many tens of thousands of miles and far out paced any harmful emissions that I introduced via the treatment.

 

[Leo]

Why dont you try Redline's SI-1? They say in their PDS that it cleans up intake valves significantly. I'd be interested to know how well it would help your car. I wanted to see the difference, but to pull the intake manifold off my car is a complete mess.

Simply 1 bottle to a full tank of fuel.

 

[uconn1150]

I really wonder if this has to deal with the type of gas you use. California seems to have really watered down (ethanol) gas. I also wonder how much cleaning agents are in your gas. Which brand do you usually use?

I used Neutra through my PCV valve and it smoked as if I was on skeeter patrol. And this was only after 30K. I now use 3oz Neutra every tankful (10 gal). I would do a cleaning through your PCV tube once per week for a month, while running Neutra (Fuel Power/Techron/something...) every tankful...then change the oil...

Keep Us up to date on the valve cleanliness!

Best of Luck!

 

[Ian Swett]

I can look at the intake valves through the fuel injector ports. Its tough to get a good look, but if I line up a small flashlight just right, I can get a decent view of every valve. So that means I can keep some track of what works and what doesn't, though it'll be hard to attribute all progress to a single thing if I alternate too much.

BG 44k is supposed to be pretty strong stuff, so I don't see how the Redline stuff could be much better, but I could be wrong and maybe I'll give that a try after running some more Amsoil PI. I've also heard good things about Berryman's.

I'm up for trying a few different things sucked in through my PCV, I just have no idea what is the best and the least harmful and how much I should be using. Also, should the car be hot already, or just started up? I've never heard of using Automatic transmission fluid for that, has anyone else used that? I would be more keen on using Neutra if I didn't have to order it. Same with Fuel Power and Lube Control.

I usually use Chevron 91, but I've used a few others(76, Arco, etc), due to availability or becaues I've heard its best to mix it up some. I was less picky earlier when I owned the car, and sometimes filled up with 87.

-Ian

[ March 08, 2004, 09:20 PM: Message edited by: Ian Swett ]

 

[JohnBrowning]

If the valves are as dirty as you claim you will probably need to run a double dose of Quick Shot, S1 etc.. THen keep useing a fuel additive for a good 6 months or so. Truth be told I would probably use Fuel Power at double the rate the first run then follow the direction from their on out!

The pistons would benifit from a piston soak . Auto-Rx will clean the ring pack.

I have to ask what oil have you been useing?

 

[tmorris1]

Seafoam introduced through the brake booster line or PCV line is supposed to do a good job also.

 

[Ian Swett]

I used free factory oil up until 12k, which was probably cheap dino, maybe the original fill was 5w40 synth? Since then I've been using Amsoil S2k 0w30. I was planning on switching to a 5w40 at some point, but there aren't that many ACEA A3 5w40's locally available.

I am currently finishing up the cleaning phase of an ARX treatment, just for good measure and in hopes that will clean up my ring pack, which I'm sure is similarly nasty. I can't say its helped a ton, but it certainly hasn't made the car worse. I think idle may be a bit smoother and quieter, but that could be in my head. I was going to switch over to a 15w40 HDEO for the rinse, since they're supposed to be stout and hold lots of crud and they're relatively inexpensive and available.

What type of piston soak? Like using lube control? (did I see this here or am I imagining it?)

I tried to take some pictures of the valves before when I had the manifold off, but they're so dark relative to the head, that they didn't come out properly.

-Ian

[ March 08, 2004, 10:07 PM: Message edited by: Ian Swett ]

 

[Milton C. Hubbard]

quote:

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Originally posted by Ian Swett:
I have some pretty serious carbon buildup on my 2000 Passat 1.8T on the intake valves and the piston. The intake valves look pretty much identical to the dirty valves in the chevron techron ads...........

So what are my best options?
-Ian

---

I'm not surprised by the high carbon buildup. You drive only 20K miles in 4 years. Probably not much highway driving in your routine and lots of stop and go driving? I doubt whether top end cleaners will have much effect in such short trip driving.

Do this: Change your oil, add plenty of high potency fuel treatment to your gas, and take a high speed road trip (70+ MPH) for a few hundred miles. The high speed operation will clean the valves and blow the carbon out of the combustion chamber. My cars have always run better after a long highway trip, and I think yours will too.

 

[Fastr1]

I have used Gm top engine cleaner and it is by far one of the most aggressive cleaners out there, but Mopar has a spray cleaner that has Butyl which is what the top engine cleaner used to have that is even better if you can let it sit soaking like overnight.

I would watch out how aggresive a cleaner I would use in fear of breaking loose a big enough chunk to get stuck in the combustion chamber damaging a rod or head or valve.

Use GM or the Mopar stuff then keep treating the fuel, Berryman B12 chemtool is a great choice and is affordable seeing you'll be using a lot for a while.

 

[Ian Swett]

quote:

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Originally posted by Milton C. Hubbard:
I'm not surprised by the high carbon buildup. You drive only 20K miles in 4 years. Probably not much highway driving in your routine and lots of stop and go driving? I doubt whether top end cleaners will have much effect in such short trip driving.

Do this: Change your oil, add plenty of high potency fuel treatment to your gas, and take a high speed road trip (70+ MPH) for a few hundred miles. The high speed operation will clean the valves and blow the carbon out of the combustion chamber. My cars have always run better after a long highway trip, and I think yours will too.

---

Actually, I've done a few longer trips recently. I went to vegas once and san diego three times. I used to drive lots of short drives, because work is only 2 or three miles away, but now I ride my bike to work, which reduces the number of short trips. But I think all the accumulation is from before, not recently. I also didn't run any sort of injector/fuel additive until 20k, so its only after the problem got pretty bad that I tried to do anything about it.

Last time I went to San Diego, I put in a good amount of Amsoil PI before I left, and I have yet to look at my valves again to see if there's any visual change, but I haven't noticed a substantial change in how the car feels.

Where is the Mopar stuff available from? I heard you can get the GM stuff from NAPA sometimes, which is right down the road.

-Ian

 

[Gary Allan]

quote:

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Also, should the car be hot already, or just started up?

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The engine should be at full operating temp. That's how it cleans the intake valves. The cleaning agent hits the hot back side of the intake valves.

quote:

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I've never heard of using Automatic transmission fluid for that, has anyone else used that?

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Unless you were a mechanic 30 years ago ..you probably wouldn't have. The technique was developed after a number of people had two conditions in their automatic transmissioned vehicles. One they had a leaking vacuum modulator (used to sense engine load for the automatic) AND had cause to have the head that the intake runner that the vacuum modulator drew vacuum from removed. That one piston/combustion chamber was clean ..while the rest were carboned up. The vacuum modulator had leaked ATF into that combustion chamber. This is mostly a "lost technique".

There have been many things used that will sound like "folk lore" to most of you. Water seems to have stuck through the ages. Uncooked rice was also used ..but I'm uncertain of the effects on the cat ..so I wouldn't recommend it. GM top engine cleaner was around back in the 70s ..it too was a PITA IMHO.

Whatever agent you use ..keep in mind that it may take several treatments to achieve the level of cleaning that you desire. That is, don't assume that the stuff you use doesn't work with just one application.

btw-I've used ATF on about 30 sensored vehicles with no ill effects (just to pre-empt and ney sayers

)

Good luck!!

[ March 09, 2004, 02:43 AM: Message edited by: Gary Allan ]

 

[Ian Swett]

I'm certainly resolved that it'll take a few cleanings before I get where I want to be.

I am concerned about blowing out my cat. I know of a guy who cleaned out his S4 with water, but in the process killed both of the cats. So I know I need to use some sort of solvent or whatever to make the 'chunks' smaller and do a few smaller cleanings rather than one huge one, so everything can burn through the cat properly.

Its possible the person's car wasn't hot enough, so instead of combusting in the cat, the chunks just clogged.

-Ian

 

[digitaldrifter91]

tkae off ur cat for an hour and do it...then u wont burn it =)

 

[Ian Swett]

I would remove the cat, but it would take too long. Its crammed right next to the turbo on my car and its tough to get at all the bolts. Its not under the car in a more conventional location.

My current plan is:
1) Look for some GM or Mopar Top Cleaner and use that through a vacuum port. If I can't find it, give the ATF or SeaFoam route a try.
2) Change the oil 10 or so miles later(ARX cleaning is done now anyway) Checkout the valves and pistons at the same time.
3) Run an in-tank cleaner, like Berryman's B12(which B12?) for a few more tanks.
4) Check out the valves and pistons.
5) Repeat full process if its still dirty. I'll be changing the oil again after 1500 miles, so that may be a good chance to run another vacuum port cleaning before I change the oil.

-Ian

[ March 09, 2004, 02:36 PM: Message edited by: Ian Swett ]

 

[JohnnyO]

I worked at an Olds-Cadillac dealer in the mid-80's. We'd use Top Engine Cleaner sometimes on trade-ins, but this was back in the days of carbs so I'm not hip on getting it into an EFI motor. It worked nice, but make sure the tailpipe isn't pointed at anything important.

 

[widman]

Use a bottle of Techron, don't overdilute it (12 oz bottle is max 12 gallons of gas). If it's really bad a second treatment might help. Use it when you will be doing short trips and it will be in for a while. I don't see it as effective if you put it in at thestart of a highway trip. I've ween it take out stuff you wouldn't believe. There are some old links on this site that have a lot of detailed problems solved.

 

[JTK]

quote:

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Originally posted by Ian Swett:
I am concerned about blowing out my cat. I know of a guy who cleaned out his S4 with water, but in the process killed both of the cats...

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This might be a silly question, but how would plain old H2O destroy a catalytic converter?? They handle water all day long during normal operating conditions & they keep on working

.
Thanks
Joel

 

[Ian Swett]

The flakes that came off his pistons were the size of small potato chips, and he did too much at once, so instead of the carbon burning up and coming out through the exhaust, it got clogged. And once a cat gets clogged, its going to die.

I think he said he did like 3 quarts the first time, and then another gallon or so a few days later?

-Ian

 

[darkdan]

Seafoam.

At $4 how could you go wrong?