Strange Sound From Within

[gerviswaddell]

Hey there, So yesterday I decarboned my engine using Takza's method of water and atf. I drove the car around to clear out the carbon (it worked just fine) , then let it sit overnight.

This afternoon I started the car and walked around to get something from in the house, when I heard a strange noise coming from under the hood. It sounded as if there were little rocks being thrown around somewhere under the hood, so I investigated. The sound was somewhat sporatic, and when I listened more closely it sounded more like little pop or crackle sounds coming from the exhaust manifold area (although difficult to pinpoint) at the time, there was also a noticeable amount of light smoke coming out of the tailpipe. Shortly afterward, the sounds stopped, as did the smoke, and I was on my way, no other issues to report. But I am curious and concerned.

Does anyone have any idea about this sort of thing? I thought maybe it could be pinging? (Ive never heard that before)

Thanks again,

GW

[Petros]

Not ping, could be the chunks of carbon you loosened from the engine now in the exhaust pipe burning when it hits the hot catalitic converter. If it does not come back, than it is an non-issue, and likely it was related to putting ATF into the engine.

[takza]

I just use straight water anymore due to all the SMOKE produced. The extra bit of ATF is just insurance to lube rings and so forth. Probably only need maybe a tablespoon for each pint of water anyway.

[gerviswaddell]

Yeah, I used less than 100ml of ATF, and a little dish soap (as instructed) any chance this carbon could damage the valves on its way out? Also, when I was changing the timing belt I had the number 1 plug out and looked inside with a flashlight, the cylinder head was covered in a fairly thick coating of carbon (looked like a dirty bbq grill!) I figure the only way to really get this out is to remove the head...which Im not in the market to do right now, any other suggestions?

thanks again,

GW

[Petros]

Breaking that stuff loose should not harm the valves. Best way I have heard, but have not tried, is to take off the airfilter and run the engine at high rpm, and dump in a can of Gumout until the engine stalls out. Let it sit overnight, soaking the piston tops and valves in the Gumout, than start it in the morning. It will blow a lot of smoke, but it should loosen most of it. You can also remove the spark plugs and squirt in the Gumout, or even ATF, overnight, which should loosen it. Some people have good luck with Seafoam, and there are other similar products as well.

There are some additives for your gas tank that claim one can in a tank of gas will clean it out. I have not experiance with how effective this will work.

I have notices that when I run it with a bad head gasket, the cyl with the leak is always clean inside when I get the head off. So just running it at high rpm with water leaking into the intake might work.

Try scraping it off through the spark plug hole with a narrow putty knife like tool?

[takza]

I once ran a qt or so of water into the intake in 50 miles or so when testing water injection (a mistake)....result was that oil use was reduced from 5K per qt to around 9K per quart for that oil change cycle.

Conclusion? ATF probably NOT needed when doing a carbon clean....a water type carbon clean probably not an issue as far as engine damage...not so sure about the O2 sensor though.

So...if you really want to do a carbon clean...run about 1 qt into the intake SLOWLY...might add some toplube in the gas though (which I always did when testing water injection). You'd want to be sure the water was going into ALL cylinders though....use the PCV system?

I just had a 1 G jug on the pass floor and used an aquarium valve to control the flow...could watch what was going on....except in this case I wasn't paying attention.