Cleaning carbon buildup off intake valves and pistons

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I should have mentioned this before, but I already got a professional motorvac clean. I think it helped a bit, but I only looked at the valves afterwards, and they were still nasty as seen in the picture above.

I guess its possible they did the clean incorrectly(wrong fuel lines), but that seems unlikely.

-Ian
 
I'd just seafoam it every 500 miles a couple of times.

Maybe it just won't ever get as clean as you want it. Also, half a bottle is a bit overkill. I use 1 oz per cylinder.

Hey, I'm obsessed with gas mileage....you stay awake at night thinking about carbon on your valves. Everyone has their problems.
 
wow, seafoam worked really well for me.

you must have crazy amounts of buildup.

bg44k is supposed to be strong and not good for continuous use.
 
quote:

Originally posted by darkdan:
I'd just seafoam it every 500 miles a couple of times.

Maybe it just won't ever get as clean as you want it. Also, half a bottle is a bit overkill. I use 1 oz per cylinder.


1oz of seafoam? I used it through the vacuum port, not directly into the cylinder as a top cleaner. In retrospect, something that sits and soaks may work better.

Since GM and Mopar top cleaner are supposed to be a bit stronger, I might try a go with those.

BG44k is strong stuff. I've only run it once besides using it to clean my valves.

-Ian
 
Yeah, I suck mine in through the vacuum too. On my crown vic I use 8 oz and on my aspire I use 4 oz and on my dad's sebring I use 6 oz. This is better than "a certain amount for all engines" as the directions state and basically eliminates the risk of hydrolocking the engine.

When you seafoamed it did you warm up the car, do it, let it sit for 30 minutes, and go drive like a speeding bullet stuck in the back end of a bat out of heck?
 
Yup, exactly that. Maybe 25 minutes of sitting, but I definitely made sure to warm it up first and drove it hard after. I may not have fed it fast enough, I think it took me 10 or 15 minutes to feed a bit over half a can.

-Ian
 
I'd definitely try one of the additive-cleaners which specifically claim to remove combustion chamber deposits to some extent. This seems well covered in the previous posts.

Another friend in addressing this matter is your gas pedal. In general, Euro engines like your Passat (although I don't have first-hand experience with that engine) tend to benefit from aggressive driving on occasion. Some of these engines, designed primarily for Autobahn type driving and revved with manual trannies, tend to carbon up when driven gently here in the States. A few years ago my friend, a former Trans-Am racer, bought an Alfa Romeo Milano V-6 in Alabama. Owned by an older woman who drove slowly, the car was a bit lethargic. He dumped some additives of unknown type in the tank, and then practically full-throttled the thing back to the West Coast. By his arrival, the car had definitely gotten spunkier, so he definitely blew a periodical chart's worth of junk out the tailpipe.

My suggestion would be to first add some cleaning agents to the tank, and then essetially drag race the thing to redline for a week or so wherever you go. Thereafter, simply do the same on occasional freeway on-ramps.
 
Yeah, I would certainly say you did it too slowly. You most likely just burnt it all up.

I warm the car up. Then turn the engine off.

Then I updo either the PCV valve, the break booster line, or this one on top of my manifold. Then I take a cup with a measured amount and place it on the engine and stick the hose in the bottom. Next I start my car and then the car dies in about 2 seconds.

I suck up 4 to 8 oz in about a second and a half. I don't sit there slowly feeding it more. That just burns it. I want liquid to rush past my valves and touch them. Then I want it in my CC sitting there soaking on the top of the piston.

Too bad I can't figure a way out to have it hit the exhaust valves....
 
I agree about driving the car hard. I've been trying to drive it at higher RPM in particular, since I've heard that helps a lot. I'm also planning on running Fuel Power for a while.

I was concerned a bit about hydro-locking the engine, so apparently I did feed it too slowly. The vacuum port I'm using is on the bottom of the throttle body, so it should have good dispersion to all the cylinders.

I should have put the seafoam into a funnel into the feed tube, then tried to start the car up and it'll die almost immediately? That seems like it'll have a pretty similar effect to when I put the BG44k onto the valves and accidentally into the cylinders.

From what I've heard, exhaust valves usually clean themselves from the heat. I don't know if I've ever heard of anyone having carbon buildup on the exhaust valves.

-Ian

[ March 22, 2004, 03:17 AM: Message edited by: Ian Swett ]
 
Yeah, at 1 oz per cylinder you'd have to do some insanely stupid to hydrolock the engine.

Next time just try filling up a cup with the right amount and sticking the hose into it. Then just start the car and it will suck it in. Then let it sit.
 
Driving a car hard, especially a turbo will just worsen the CC deposits IMO, as the car runs very rich at high RPM and load.
 
Well you're supposed to drive it hard after doing a seafoam cleaning.

You're trying to get the rpms up and get everything to fly out of there and burn everything off.
 
Leo is right. In my case, I tried to drive it hard without going into much boost. But since I did the treatment incorrectly, its sort of irrelevant. I'll give it another try soon, though.

-Ian
 
I checked out the valves yesterday and they looked mostly clean. One or two were still oddly nasty, totally carboned up, but the rest looked fairly normal. Much better than last time I checked. So I'm going to have to give some credit to the SeaFoam, even if I didn't use it optimally.

For the valves which are still very black, can I put some FP or LC on it and let it sit overnight(or a bit longer) to try to clean it off? That seems like it might work like the Molasoak does, only on the intake valves?

I may still check the pistons and consider doing the molasoak. I haven't decided between that and just using FP in the gas.

Thanks for everyone's help. The car has been running a lot better lately, though I think its not quite back to 'like new' status.

-Ian
 
The problem with pooring things directly into there is that things are going to seep past your rings and get into your oil.

I'm not sure if you want FP in your oil. I just ordered some FP and can't wait to use it. If I were you I'd just put it into the gas.

Why not use seafoam a couple of times again? Nothing can work perfectly the first time. Just do it once before every oil change.

I'm seeking help. You should too. I'm over at gasmileagaholic anon. They're really helping me with my problems. I'm no longer staying up late at night thinking of how to get another mpg. Maybe there's a dirty valve anon you could check out. =) You know, before you rip your head off and disassemble it.
 
Sorry, I should have only mentioned putting LC on the valves, I forgot that FP would be incompatible with the oil when it went past the rings.

-Ian
 
Since you had a pretty serious carbon buildup, you should check the EGR valve passage as well. The EGR valve is a spendy item and a little preventive maintenance would go a long way.

Ð
 
Really Ian...do the Lube Control soak and Fuel Power in the gas. The stuff works as advertised, if not better. I'd have to say that you are spinning your wheels a bit.
 
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