Sea Foam for intake valve carbon buildup: results

This is a report of my experience with Sea Foam. If you do what I did (you know, professional driver on closed course... yeah right) you might get hurt or hurt someone else. Let your mechanic do this for you.


My '08 535xi was beginning to run rough on acceleration and the power output seemed reduced. Various threads on this forum ( http://www.bimmerfest.com/forums/sho...light=sea+foam ) indicated that it's a common problem with the N54 and other direct injection engines.

It was mentioned that dealers charged ~$500 to fix the problem. People mentioned removing the intake manifold and blasting the valve area with walnut shells or using brushes etc. Rather than remove the manifold even to inspect it, I decided to just try Sea Foam. Here's what happened:

I got the Seam Foam Spray Cleaner & Lube with the long red applicator tube. I pulled the large charge air tube off the throttle body, stuck the tip up into the throttle body then partially replaced the air tube (you can't put it back completely due to the coupling but that's ok). I used my ice scraper jammed up between the accelerator pedal and the seat to increase engine rpm to about 1500 then sprayed in 1/2 can. Then let it sit for 5 min just like the instructions said. Next I re-attached the air tube then immediately went for a full-power run. When I hit the throttle it popped and bucked a little then out of this huge cloud of blue smoke it took off like a bat outta hell!

This tuff really worked! I did a few brief full power runs and afterward it accelerated smoothly. Cost me $10. I saved $490 over the dealer price!

If I were to do this again I would let it sit for 10-15 minutes before starting the engine and even then I would repeat the treatment immediately to remove any residual carbon.

Without seeing carbon build up (with a boroscope, for example) nor confirming removal of it (if there ever was any), how can you be so sure Sea Foam worked? I want to believe, since at some point my car will need to be de-carboned, but it would be nice to have more empirical data vs. a gut feel.

If you're interested, we (over in the E39 section), took a good hard look at what Seafoam is and what it does ...
- What is Seafoam motor treatment, what does it do, where do you put it, and how does it work (1)

Actually I was ready to use an old flexible sigmoidoscope (short version of the thing the doctor sticks up your butt to do a colonoscopy) to look at it to be sure. But the wind chill was about -35F and i'd have to be working outside at the time. My logic was that it wouldn't hurt to try the Sea Foam and it worked. But you're correct that I can't say for sure that carbon was causing the problem. I figure a 60% chance based on symptoms alone (at least better than 50:50), 75% based on response to Sea Foam. I think that gives an overall probability of 90%. Feel free to correct me if I'm wrong.

Others have posted pictures of the carboned up valves. The symptoms they described are exactly what my car was doing. So, I wouldn't call it a gut feeling. My gut feeling was that it was something electrical until I ran across this valve problem here in the forum.

Anyway, think of a favorable response to Sea Foam as being a positive test. But the test has a false positive rate too (as well as a false negative rate as in "what if it didn't work and it really was carboned up?") So, there was a positive test in a situation where there was already a fairly high probability that the condition really did exist. It that situation the false positive rate is really low. On the other hand if you have a positive test in a situation of low probability then there's a pretty good chance the test is wrong.

The Sea Foam people might have some data on this but I doubt it.

It is possible to reduce carbon build-up at the intake valve edge using an injected or atomized solvent such as seafoam, and therefore get better combustion chamber sealing.

You are relying upon the forceful and unexpected introduction of a foreign liquid, which does not combust like gasoline, into the combustion chamber though. In addition, you are relying upon carbon to be dissolved or broken off the intake valves in a very sudden way.

The primary chance for harm is hydrolocking your engine (sucking up too much before it burns out of the cylinder) or breaking off a LARGE chunk of carbon. The other fears are mostly poorly founded - a car can consume a quart of solid motor oil in the combustion chamber without fouling the cats/o2 sensors; and pale oil will burn far cleaner than motor oil.

Further, your combustion chamber has to deal with small bits of carbon from time to time. They are combusted and blown out the exhaust valves. They either get stuck in the exhaust and burned away over time, or blown out the exhaust altogether. They don't "scratch" the cylinder walls.

I have a feeling, Seafoam is like chemotherapy for common flu. I'd pay dealer $700 every 3-4 years to get carbon cleaned the right way, walnut blasting, that is.
A friend shows me how Seafoam stains plastic and eat away a rubber hose, that stuff is corosive as hell. Not sure what happened to turbo and catalytic converters in long run.

Its hard for me to believe that Seafoam cured DI carbon build up problems in the same way that walnut blasting would.

I'll try to take a look at it and see. By the way, when I started it yesterday am it went into what I think is limp mode: Sort of a surging idle as if someone pumping accelerator and when I push the accelerator it only goes to about 2000 rpm. Who knows. Maybe I killed it!

Originally Posted by chintonmd

I'll try to take a look at it and see. By the way, when I started it yesterday am it went into what I think is limp mode: Sort of a surging idle as if someone pumping accelerator and when I push the accelerator it only goes to about 2000 rpm. Who knows. Maybe I killed it!

Doubt you killed it. I think you should just take your car to the dealer or independent specialist and eat the cost. Your car could need injectors or walnut blasting, hard to tell given that description. These cars sure aren't cheap to run!

Originally Posted by Serpens

Its hard for me to believe that Seafoam cured DI carbon build up problems in the same way that walnut blasting would.

Placebo effect is as powerful as walnut blasting. For the short term, at least.

I finally had a dealer who was willing to go to the mat for me with BMW. So, having tried the HPFP (third one, I think) and replacing injectors, again not resolving the problem, they allowed the dealer to remove the valve cover and send pics of the valves which were, indeed, covered in carbon deposits. So the walnut blast was authorized and covered under CPO!!! Car runs like original with tons of smooth pwer again. Frankly, given all the hassle, I'd do it again in a second and just eat the $500.

Originally Posted by themust

I finally had a dealer who was willing to go to the mat for me with BMW. So, having tried the HPFP (third one, I think) and replacing injectors, again not resolving the problem, they allowed the dealer to remove the valve cover and send pics of the valves which were, indeed, covered in carbon deposits. So the walnut blast was authorized and covered under CPO!!! Car runs like original with tons of smooth pwer again. Frankly, given all the hassle, I'd do it again in a second and just eat the $500.

Hey I noticed your from the Bay Area, what dealer did you take your car.

For $500, that indicates to me that we're talking about 3 hours of dealer labor on average. Kinda makes me wonder if an Indy would charge $300, ya know?

You might have a hard time finding an indy with walnut blasting equipment.

Originally Posted by Stephen Max

You might have a hard time finding an indy with walnut blasting equipment.

+1

I've called numerous indy shops and i get the same answer from all, the tool that connects to the intake for the blasting and vacuuming is super expensive. I've seen some people modify a shop vac wand tool but the shops tell me they would only use the correct tool. So far i have only found one indy shop in the bay area to do it and it is about $550 to do the blasting and it takes about 4-5 hours.

Originally Posted by JoeFromPA

For $500, that indicates to me that we're talking about 3 hours of dealer labor on average. Kinda makes me wonder if an Indy would charge $300, ya know?

I had it done for $320 by an indy, including new gasket.
It was done by 2 guys in a garage. They use a wetvac to suck out walnut shells and carbon deposits. The whole procedure took 3 hrs and is worth doing if your car has over 50,000 miles. They use a wand that shoots compressed air with walnut shells via an aluminum cup that fits the opening of the valve chamber.
Interestingly my sedan which has a meth kit was pretty clean in cylinders 5 and 6. This is due to meth actually dissolving carbon build up as it passes through the throttle body and into the intake.

Burger Tuning sells an oil catch can that supposedly separates off any oily sludge so it doesn't reach the intake. http://www.burgertuning.com/BMW_335_oil_catch_can.html
I don't have it installed so can't comment on how well it works.