Quote:
Originally Posted by Rawhide
Water?!?! Serious bravery there...
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Yes, water really. Its an old trick. You introduce some water via a vacuum line. You do it when the engine is fully warmed up... the water vapor gets sucked thru the intake manifold... and the water droplets cool the hot carbon on the intake valves. This causes the carbon to crack off the valve. Do it long enough... and your'll remove a lot of carbon that gets built up.
Do it WRONG... by letting the engine GULP down the water... and well... we all know water does not compress like air... so you can end up bending a connecting rod.
I know a lot of subbie techs who do this on Subaru's flat four. Those engines are famous for carbon buildup! But... going in with dental scrapers or a gun cleaning kit is better and more thorough in removing MORE carbon builtup.
Personally I think the best way is to use Seafoam - spray it on the intake valves... let it soak a day or two... then go in there and scrape off the crud. Or... maybe that walnut shell media blaster that Harbor Freight sells. The walnut shells get impacted at the intake valve... what old walnut shells you miss to clean up... will get burned off in the exhuast anyways. I think that is a good option as well.
Dackel