[Toad335]

So my dealer service department has a brochure for fuel system cleaning. They show pictures of the carbon coated valves before and clean ones after. I asked how much, know that people are paying $400-$800 for walnut blasting. He said $169! I asked what it consists of and he said they hook up a Techron "vaporizer" to the intake and run the engine. This allows the Techron to hit the top sides of the valves and clean them out. He said the exhaust will smoke like crazy for a few minutes and when it stops they are done.

Has anyone else heard of this, or better yet done it? I've got 45k miles and am seriously considering it... I did ask if I could get before and after pics of the valves, but he said no. Given that they probably aren't going that far into the engine it makes sense I guess...

[Bimmer Barney]

Search and you'll find it does nothing.

[Javier]

walnut blasting or wire brushing+chemicals

nothing else works

[Toad335]

What I found when searching was that techron in the gas does nothing, which makes since because of direct injection. This sounds different and I was having a hard time finding anyone referencing this service (except something maybe similar on another board...and he said he thought it made a difference)... Any other input?

[N54King]

Couldn't hurt to try it out ... sounds like it works in theory considering it is going through the intake . However couldn't imagine it cleaning as effectively/intensively as traditional methods.

[Rotorocious]

Waste of Money

[roadkillrob]

Might help if you did it regularly before the buildup gets too bad, like every 10k miles. The smoke is probably just the techron burning up and stops when the bottle of techron is empty. I would want to see a before and after pic of the valves before shelling out the $169. See if they will scope it before and after for a bit more money to prove it cleaned them, otherwise your just buying it on faith!

[benzy89]

This Techron cleaning will be just as effective if you went to PepBoys/AutoZone and bought Techron ($10) and put it in your gas tank. At best, you're injectors will get cleaned up.

The intake valves will remain clogged until they specifically get cleaned, whether you decide to Walnut Blast or a Chemical Bath/Wire Brush Scrub

[GeorgiaTech335coupe]

OP stated they are sucking in the Techron through the intake, so the valves will see it. I'm not sure how effective it will be though, I guess it depends on how long the process takes. I'd want to see before and after pics, otherwise I'd be very skeptical.

[ErvGotti]

People have tried this method with Seafoam though the vacuum line on the intake manifold. It does nothing if the carbon is heavily caked up. I believe on N54 tech there is a good write up that shows it does nothing for our engines. Also is you are going though with this make sure they are sucking the Techron though that vacuum line on the intake manifold and not through the intake it self. I wouldn't want Techron hitting my turbo's.

[Bigugly]

Fuel additive in the exhaust will not harm your exhaust turbines.

[brusk]

Alot of dealers offer this type of cleaning system with a pressurized canister and a hard line with and injector that gets slid in between a connector probably in the charge pipe area. This would be comparable to running techron through a small meth nozzle which people have said they've tried and slows down the build up but doesn't get rid of it. This would be a nice setup to have at the house and do every oil change and preventative maintenance.

[GAM]

I have read a lot about the walnut shel blasting but I decided to do the valve soaking and brushing to get the carbon deposit out (mainly because I didn't have to buy so many things such as a compressor, the BMW tool...). When you realize with how much force those walnut shells are hitting the carbon you realize that's you need something very strong to hit the carbon with, or to let them soak for a while in a liquid that's very "corrosive" if I can say. I've done mine with carb cleaner and gun brushes and it's not that easy to get everything out. So it makes me think that just vaporizing some techtron in a liquid version is not going to remove much, especially that the valves are not even soaking in it, just getting vaporized with it..
If you find someone that can do the blasting for $300 go for it. I did clean mine with the carburetor cleaner, took me 4 hours but costed me $40..

[eric@helix]

Unfortunately, these techron and sea foamy methods don't work. Neither does Meth or catch cans.

[Beemw335]

Originally Posted by eric@helix

Unfortunately, these techron and sea foamy methods don't work. Neither does Meth or catch cans.

Meth help reduce buildup
But wont remove any current buildup.
Catch cans do nothing for carbon buildup.

[cleex024]

i think the best way to do it is to do a combination of walnut blasting plus scraping with a screwdriver and dental teeth cleaning set. ive done like 4 cars in the last week and seems that is the best way to do it...everyone on here that only uses walnut blasting is not getting the layer of gunk on the walls of the valves.

ive gotten is down to where i can do it in 4 hours from uninstalling to you driving away...but it is a lot of work.

by the way why doesnt the oil catch cans work? i was actually hoping someone could make something that you could put in your intercooler maybe or either some kind of extremely durable cloth or sponge where it can soak up the oil while not interfering with air flow.

the other stuff like techron cannot work because its just way too hard and its really stuck on there...u would know if you have ever tried to scrub off the gunk.

yeah if you can get someone to do it for $300 i would definitely pay for that...it really is a lot of work and resources you need do it on your own. i actually bought about $1000 worth of tools/compressor and such to do this plus a lot of trial and error where now i have everything and dont need to go to the store to pickup little things here and there.

[VSmotorsports]

We had a customer come in who had this done on his 335i. He did not feel a difference so we went ahead and did a valve cleaning, ended up looking the same as many of the other cars that we have done.

[Jeff@TopGearSolutions]

I think there is a misconception what is actually going on here in terms of why there is carbon build up on the intake valves.

There is simply carbon build up because it's a by product of direct injection motors.

In your typical port injection motor, fuel is run over the valves and therefore is in theory always cleaning them. Since a direct injection car has the fuel injectors in the combustion chamber, there is no fuel hitting the intake valves, therefore no cleaning.

A by product of combustion is carbon build up and by no accident, if there is nothing cleaning the valves like fuel, the result after usage is build up.

The purpose of an oil catch can is to limit the amount of oil in your intercooler, charge pipe, and entering back into the valves. The oil that a catch can would normally capture is only a small portion of the build up on valves. They will inevitably build up with carbon no matter what anyone does.

Methanol could subtract a tiny amount of build up but it is not a cure either.

Fuel injector cleaner won't do anything because the fuel injectors are in the combustion chamber, so no fuel will see the top of the intake valves.

I hope that clears up everything.

[Munit]

So why are some motors from other carmakers worse than others? Seems like a huge problem in robbing power and mileage ever 20k miles or so as well.

Was their really a need to go DI with other engine tech. Sure you can make 10-15 more hp with a similar setup Di vs regular and you can cool the intake charge a bit better but with cylinder design and the tech they have, I would have much rather had regular injectors that would not cake up every 20k. I got an m3 and love the fact it has no DI. Just a classic 4 L v8 with regular injection. The way cars should be!

[See5]

Originally Posted by Munit

So why are some motors from other carmakers worse than others? Seems like a huge problem in robbing power and mileage ever 20k miles or so as well.

Was their really a need to go DI with other engine tech. Sure you can make 10-15 more hp with a similar setup Di vs regular and you can cool the intake charge a bit better but with cylinder design and the tech they have, I would have much rather had regular injectors that would not cake up every 20k. I got an m3 and love the fact it has no DI. Just a classic 4 L v8 with regular injection. The way cars should be!

DI is fine if you do it right. I've heaven't heard any problems with carbon buildup on any of Ford or GM's DI motors.

Yes, DI is the way to go in the long run. Your M3 motor would make more power, get bet better fuel economy, and probably allow the ECU guys to play a few tricks to get emissions down as well. There's really no downside to gaining precision in fuel use.

[cleex024]

Originally Posted by Jeff@topgearsolutions

I think there is a misconception what is actually going on here in terms of why there is carbon build up on the intake valves.

There is simply carbon build up because it's a by product of direct injection motors.

In your typical port injection motor, fuel is run over the valves and therefore is in theory always cleaning them. Since a direct injection car has the fuel injectors in the combustion chamber, there is no fuel hitting the intake valves, therefore no cleaning.

A by product of combustion is carbon build up and by no accident, if there is nothing cleaning the valves like fuel, the result after usage is build up.

The purpose of an oil catch can is to limit the amount of oil in your intercooler, charge pipe, and entering back into the valves. The oil that a catch can would normally capture is only a small portion of the build up on valves. They will inevitably build up with carbon no matter what anyone does.

Methanol could subtract a tiny amount of build up but it is not a cure either.

Fuel injector cleaner won't do anything because the fuel injectors are in the combustion chamber, so no fuel will see the top of the intake valves.

I hope that clears up everything.

i dont get it...why would there be carbon build up in the intake portion if the combustion takes place else where? the combustion is not in the intake valves...

im pretty sure the reason why there is carbon build up is because the oil from the turbos get all the way into the intake valves and the heat from the engine sort of hardens/burns the oil onto the vales.

i bet that if there was no oil going into the intake valves there would be no carbon build up.

[Jeff@TopGearSolutions]

Originally Posted by See5

DI is fine if you do it right. I've heaven't heard any problems with carbon buildup on any of Ford or GM's DI motors.

Yes, DI is the way to go in the long run. Your M3 motor would make more power, get bet better fuel economy, and probably allow the ECU guys to play a few tricks to get emissions down as well. There's really no downside to gaining precision in fuel use.

Hmm I wouldnt say Ford or GM DI cars have had no carbon build up, but they have done a good job on their 2nd gen motors to reduce it for sure. Direct injection is the ideal method of fueling, assuming they get the carbon build up issues correct, the injector failures limited as well as any fuel pump problems.

As technology has improved so has DI. It will likely be the future for most car manufacturers and models in their line up.