Removing carbon buildup

[tici]

The modern method (without opening the engine) is to use products like GM Top Engine Cleaner.

Older methods are:
- ATF mixed in the oil
- ATF mixed in the gas
- Brake fluid misted in the intake system (similar to the GM Top Engine Cleaner procedure)
- Water misted in the intake system (similar to the GM Top Engine Cleaner procedure)

Who know how good / bad are those methods?

Stefano

 

[VaderSS]

Don't know what effect, if any, that Brake Fluid would have on cats.

Another one I've used is MMO.

I just run Fuel Power in the fuel. I'd use water if I were just going after carbon and wanted it out quickly.

I'm a big fan of Amsoil Foaming cleaner, for a nasty upper intake. I'm sure it takes out the carbon as well.

 

[addyguy]

Water, either misted into the intake, or sucked through a vacumn line, is really effective AND really cheap, so you get 2 good points with that method...

 

[VaderSS]

And it should have zero impact on sensors and cats...

 

[MGregoir]

Originally Posted By: addyguy
Water, either misted into the intake, or sucked through a vacumn line, is really effective AND really cheap, so you get 2 good points with that method...


I would be worried about unintentionally hydrolocking the engine doing that though. At least something like Seafoam is combustible.

 

[Quest]

My concerns revolve around emissions control stuff downstream: pre and post O2 sensors, cat convertor (the late model OBD-II ones with the ability to store NOx for conversion are expensive!).

And I'm never entertained by the very idea of drastic measures such as ATF (not meant to be used that way, will cause all kinds of weird codes downstream), brake fluid, etc. Old tricks die hard and there are many, many tricks that fall short of that category.

Unless you are doing a lot of Regaine and an extended highway drive shall suffice.

BTW: modern blended gasoline suitable for EFI car of all sorts already comes with sufficient detergent to prevent carbon from forming on the back side of the intake valves/combustion chamber (*unless your valve guides are worn causing oil burning issues, or your EFI system is running rich due to ricer mods or malfunction emissions-related sensors, etc.). Coupled with precision EFI engine designs with precise computer management, car engines don't carbon up as much as they used to back in the pre FI days.

If you still believe that your engine is all carboned up and none of these tricks entertain you, do it the old-fashion way: pull the head off and start scraping.

Cheers,

Q.

 

[VaderSS]

Originally Posted By: MGregoir


I would be worried about unintentionally hydrolocking the engine doing that though. At least something like Seafoam is combustible.


You have as much chance of hydrolocking the engine with seafoam as you do with water. Yes, Seafoam is combustible, but if you dump a big enough slug in, it's not going to burn, because there will be no air in with it. The amounts to hydrolock are going to be the same, whether it's Seafoam, or water.

As with any mechanical procedure. If you are unsure of what you are doing, you better not do it.

As for no carbon build-up with modern fuels, I've seen too many pinging modern engines stop pinging after a top-end cleaning to believe that. Modern engines typically run a bit rich, to keep the cats working at their best, and that causes build-up. Might take 100k, but it happens.

I have seen the latest fuels from Shell perform similar to Fuel Power, so I believe that there will come a time when all fuels behave the same, but currently, they do not.

To say that you should pull the head to do that top-end cleaning is pretty rash. Water does the job without affecting sensors and cats. I do sometimes get a code after using Amsoil's cleaner, but then the code clears up quickly and the engine is running smoother after, so I'll stick with my way.

 

[Dyoel182]

No need to pull the head unless your EGR passages are totally clogged and its your last option.

 

[Spitty]

How about taking the car for a good hard drive? It's sometimes called an 'Italian tune up'.

 

[Dyoel182]

That clears out some valve deposits but not much in the throttle body or EGR.

 

[XPR]

Seafoam via a vacuum line, Amsoil Power Foam via the air intake, Lucas Fuel Treatment in the fuel, Amsoil P.i. in the fuel.

 

[Dyoel182]

SeaFoam spray would be the cheaper alternative to Power Foam.

 

[VaderSS]

Does SeaFoam Spray actually foam up, filling the intake?

That's what I like about Amsoil Power Foam. It looks like shaving cream going in and get into all the crannies.

 

[XPR]

I've never seen SeaFoam in a spray form where I live.

 

[ziggy]

Get a spray bottle, and fill with about 24 ozs NO more, of distilled water, not sink water. Sray seafoam via the throttle body,a nd keep they throttle open, with car running... then spray water into the intake after youve let the seafoam soak clean ect... that way, you dont risk hydrolocking.
Just remember!!! Prob a good idea, to change those spark plugs, after doing this. If you can remove the EGR tube, and soak n clean it out also. I did this 2 or 3 years ago, in my 95 neon...egr tube was 80% closed- up in gunk.

 

[Dyoel182]

Must be nice to be able to remove the EGR tube.

 

[tici]

Thank you guys for your answers!
This is a 98 Trans Am with a 5.7L LS1 Engine.
The engine is supercharged (just 5 PSI) and is internally stock.
I don't have an intercooler but I spray water/alcohol to cool the charge air.
The EGR is OK, I replaced the valve with an orifice (it's a common mod for this engine).
I have a catchcan between the EGR "valve" and the intake because those engines are known to let some oil going throug this system.
I installed the catchcan late, when the engin has already 50'000 miles (it has 85'000 now).

There is a pinging noise at 1000 rpm when the engine is cold, when hot it appears at 2500 rpm (??).
BEfore I start taking the engine apart I want to be sure that it's not a dirty lifter (those are hydraulic rollers) or some carbon in the combustion chamber.

I was looking for a cheap system to clean the inside of the engine and the top end... over here (Switzerland) we don't have your products (stuff like GM top engine cleaner or Seafoam).
We just have additives to mix in the fuel.

 

[MattPersman]

with the water/alcohol injection I would think there should be not too much carbon.

 

[mechtech2]

Trickling water into the intake is the only one of those that I'd ever use.
And I would warn AGAINST the others.

 

[Gary Allan]

Originally Posted By: MattPersman
with the water/alcohol injection I would think there should be not too much carbon.


That would be my feeling too. If you process enough fuel in a timely manner, water/alcohol can be tolerated in decent amounts in the tank (think dry gas - but with better alcohol)