Should I do it before or after?

 

Depends on how you plan to use it...through the gas lines? Down the TB? Vac line? I would suggest before, just incase of the broken down particles end up suspended in the oil. It should all stay w/in the combustion chamber and out the exhaust, but just incase.

 

How long do you think the smoke show will last?

 

Would definately do it before Oil change, specially if ur doing it through the gas line. Smoke all depends on how much gas you got in the engine... I think?

 

The smoke depends on 2 things, how much carbon build up you have, and how long you let it soak. This only happens if you put it thru the intake, not the gas tank.

unless you put it in the oil, it should have a negligible impact on the on the engine's oil.

 

I just do it before a tune-up. Mine hardly smoked at all and did the whole can down the brake booster and throttle body. Then I changed oil and plugs. Some say that excessive carbon burning off can foul plugs.

 

before

Both Chrysler and GM believe that Seafoam is not as effective as their product
either 'top cylinder cleaner' from GM
or Chrysler 'combustion chamber cleaner'

 

Shocking!


Really, first I read they choose Mobil 1 as oil of choice, now THIS! Next you'll be telling me there's a woman running for president.

 

Not to take either side but, I've used both and I feel I got more carbon out with the MCCC than seafoam. I think the aerosol property of the MCCC was the biggest factor as it probably coated more uniformly and the foaming actionmight have penetrated the carbon deposits better. Both were run according to the can's instructions and allowed to sit overnight. Both smoked to high heaven, but the truck ran noticably smoother after MCCC.