Today I came across a couple people talking about how great water is at "decarbonizing" engines when (very slowly) sprayed into the throttle body or sucked into the brake booster vacuum line, like you would with seafoam. I've never heard of such a thing. I mean, it just sounds like a bad and/or ineffective idea when you hear it for the first time. But to my surprise, when I looked it up alot of people seem to rave about how safe it is to use and how well it works. I'm not convinced. Still sounds like "an ole' trick" my grandpa would teach me or something. But really have any of you guys heard of this?

 

It works very well

Tested with boroscope

Water/meth injected engines always look super clean when broken down

 

I guess it could be considered safe if you regulate very very cautiously how much goes in. ^^ in the case of water/meth injection it is regulated. The water literally boils(?) the carbon off. But if you let too much in you could risk a hydro lock at the very worst.

I'd feel sketchy about it too

 

Its not much different from seafoam. You put too much seafoam down your intake and it'll hydrolock as well.

 

I have seen it done...it was for an engine that was knocking due to carbon buildup on the piston, and it was hitting the cylinder head. It was some 4 cyl ford engine I remember.

While revving the engine very high (around 3500 on a 5500rpm redline engine) the guy dipped a large vaccuum line off the engine into a cup off water and sucked up a few teaspons. It broke up the carbon instantly and eliminated the knock.

I think its an extreme procedure and used for last resort repair.