Just a little heads up for seafoam newbies..
I've been using it for years on probably 15 different vehicles without issue. I SWEAR BY THE STUFF!
BUT..!
My 2001 Tahoe LT has 250k on the 5.3 and it was running sluggish. I came to the conclusion that it was carbon buildup and I needed to do something about it.
First I did the seafoam.. half through the booster hose and the other half in the tank with 8 gallons in it. The usual..It did what it was supposed to do.
Secondly I did some research on using E-85 as a cleaner and octane booster. I found that mixing 30% E85 to 70% premium (92oct) worked wonders! It really cleaned my engine and fuel system out nicely! Much better than I expected in fact! And my truck ran like it had never ran before!
So I continued to use the E85/Premium mixture every other fill up. The truck kept running strong and steady.
Well, to make a long story short I ended up getting a misfire while driving down the freeway. Figured a coilpack or something?
Get it to my buddies, put it on the scanner, found random multiple cylinder misfires.
After a little diagnosis we find that there is no compression on cyl.#1..
Cause: **A chunk of carbon buildup the size of a dime became lodged in the exhaust valve and hung it open long enough to cause bigger problems!
Outcome: Used engine with 120k on it
Lesson learned: Do NOT try to rapidly/aggressively de-carbon a high miles engine!
