Seafoam
Le Mans Master
Joined: Mar 2004
Posts: 7,473
Likes: 1,495
From: Little Rock AR
FWIW - I bought 2 cans. Ran one through the Fleetwood gas tank (has a Chevy TPI motor) it helped the off-idle hesitation noticeably. You could feel it right away. I did not notice any odor or smoke. The only problem was once the tank of gas was gone, the improvement went away. I still have the other can in the garage.
-Mark.
-Mark.
Drifting
Joined: Sep 2006
Posts: 1,986
Likes: 21
From: Columbus MN
SeaFoam is a broadrange solvent. If you need to dissolve something, then it may be worth a try. If you don't it's not. For me, my Vette sits from November to April. Fluids evaporate in the fuel and lubrication systems.
I put a can in the fuel tank before I take it out for the first time to clean dried on deposits from the pickup filter to the carb. I also add a can to the crankcase before I drive it enough to warm the engine up and then change oil and filter.
The results are expecially noticeable when I do or don't use it before an oil change. When I use it before, the oil is clear on the dipstick when I check the oil level after the oil change. When I don't use it, the oil is gray when I check the level. The way the engine runs with and without a can in the fuel tank after sitting 5 months is noticeable too.
I haven't tried it in the vacuum lines like DB has, but it makes sense. Crud builds up in vacuum llines and vacuum controls too. SeaFoam probably dissolves that junk too.]
It's no big deal if you don't use SeaFoam though. If build up isn't a concern, then don't bother.
I put a can in the fuel tank before I take it out for the first time to clean dried on deposits from the pickup filter to the carb. I also add a can to the crankcase before I drive it enough to warm the engine up and then change oil and filter.
The results are expecially noticeable when I do or don't use it before an oil change. When I use it before, the oil is clear on the dipstick when I check the oil level after the oil change. When I don't use it, the oil is gray when I check the level. The way the engine runs with and without a can in the fuel tank after sitting 5 months is noticeable too.
I haven't tried it in the vacuum lines like DB has, but it makes sense. Crud builds up in vacuum llines and vacuum controls too. SeaFoam probably dissolves that junk too.]
It's no big deal if you don't use SeaFoam though. If build up isn't a concern, then don't bother.
Safety Car
Joined: Aug 2002
Posts: 4,812
Likes: 1
From: New Albany IN
St. Jude Donor '03-'04-'06-'08-'09
I don't know if this is a coincidence or not, but I put a can in the tank of my '71 and my tank started leaking right after that. Three little rust holes came out of hiding. If the seafoam caused it, I would assume the previous owner lined the tank to "seal" it and the seafoam ate it away.
Just a thought.
Just a thought.
Pro
Joined: Nov 2007
Posts: 741
Likes: 1
From: Woodstock GA
I have had good luck with it on used, poorly maintained engines...it definitely has helped, and the benefits (smoother running. less pinging, etc) haven't gone away. Its also great for finding exhaust leaks...just look for the cloud of stinky white smoke! 
