I'm a fan of Seafoam and Chevron Techron
Here's a published article I like and to consider:
Additives
Fuel Additive TESTS (including Seafoam) This can be argued all day, some
time back I looked for objective results. Used to use Seafoam. Now I use
Duralube Fuel System Treatment based on this person's testing. He used
tar (similar to gas varnish buildup) and checked a comprehensive list of
solvents on it. Note where Seafoam was rated. This is just one persons
test, but it's the best data I could find based on some level of testing, hence
I use Duralube. This also indicates not to use STP, I believe last time I had
the tank off the pep-cock screen is nylon.
Background about tests: As a worst-case sample of material which might
be found in gasoline I used ordinary tar. The brown deposits we find coating
carburetors, and which collects in fuel injectors and on intake valves, are
the highest boiling components in gasoline. They are tar-like materials
which distilled along with the lighter gasoline.
The best solvent I've ever seen for these was methylene chloride, but it's
expensive and I'm sure it's being phased out to protect our ozone layer. In
any case, if you used it on a modern car the chlorine freed during
combustion would corrode the oxygen sensor. Amoco advertises a cleaner
gasoline and I'm sure it's because they've reduced these tar-like
compounds. All gas these days contains at least a little detergent of some
sort to help keep these deposits from building up too much.
Dimethylformamide is listed in the literature as being a good engine cleaner
and is "especially good at dissolving carbonaceous deposits". I haven't
used this myself because it is a bit too toxic. Instead I used N-methyl
pyrrolidone, which is also good.
For my tests, I tried to use a wide variety of products, well known and
unknown, expensive and cheap, and also some pure solvents in order to
represent a good cross section of products on the market. Note, carbon
itself (such as soot and other thermally decomposed material) is not soluble
in ANY solvent but solvents like dimethylformamide and N-methyl
pyrrolidone do a good job of breaking up clumps and dispersing the fine
particles to release the heavy tarry materials trapped within them. However,
some of these solvents are too harsh to use freely in the fuel system.
(Someone in one of these forums told me that when the auto industry looks
for good cleaners, they mostly look for solvents that will not attack the
plastic and rubber parts in the system.)
Most cleaners (the safer & slightly less effective ones) usually have
common solvents in them like toluene, alcohol, acetone or methyl ethyl
ketone, and naphtha. If you want to use these to clean your system, you
can get more for your money by buying the pure solvents at a hardware
store and mixing them yourself. I have never had a problem adding toluene,
acetone, alcohol, or naphtha to my gas tank in quantities up to one quart
per 16 gallons.
Most of the straight solvents I used are at least as flammable as gasoline
so be careful if you use them. The alcohol used was pure, 100% isopropyl
alcohol. This has no water in it, it is not the same as "rubbing alcohol".
These test results are as fairly and accurately done as I could manage with
the equipment I had available, and the other data presented is also
accurate to my knowledge. Your car may have different plastics in it than
mine does so if you choose to make your own cleaner, do it at your own
risk.
TEST RESULTS RELATIVE EFFICIENCIES AT WHICH VARIOUS
CLEANERS WILL DISSOLVE HIGH BOILING RESIDUES FROM
GASOLINE AND CARBONACEOUS DEPOSITS FOUND IN USED
MOTOR OIL, (10=BEST): ·
10 Gunk Gas Treatment ·
10 Toluene (a common ingredient) ·
9 Castrol Syntec Power System ·
8 Duralube Fuel System Cleaner ·
7 Gunk Fuel Injector Cleaner ·
6 Redline SI-1 ·
5 Gunk Air Intake Cleaner ·
4 Naphtha (a common ingredient) ·
4 STP Fuel System Cleaner ·
4 Seafoam Motor Tuneup ·
4 Trak Fuel Injector Cleaner ·
4 STP Intake Valve Cleaner ·
4 CD-2 Emission Cure ·
4 Prolong Fuel System Treatment ·
3 CD-2 Fuel Injector Cleaner ·
3 Techron Concentrate ·
0.5 Butyl Cellosolve (a COMMONLY used "AUTO INDUSTRY
DETERGENT" for oil and grease)
THE FOLLOWING CLEANERS DO NOT HURT NYLON (LISTED
RANDOMLY). (The letters in parentheses indicate how well they dissolved
the material from used oil, A=best.): · Toluene (A) ·
2-Phenoxyethanol (A) ·
Duralube Fuel System Treatment ( B) <<<<<<<<<<<<<<<< ·
B-12 Chemtool ( B) ·
Trak Fuel Injector Cleaner © ·
Techron Concentrate (D) ·
STP Intake Valve Cleaner (E) ·
Seafoam Motor Tuneup <<<<<<<<<<<<<<<<<< ·
CD-2 Emission Cure ·
Prolong Fuel System Treatment ·
Aromatic distillates · Naphtha · Butyl cellosolve · Acetone
THE FOLLOWING CLEANERS WILL DECOMPOSE THE NYLON SOCK
IN THE FUEL TANK. Listed in order of increasing severity:
· STP Fuel System Treatment
· CD-2 Fuel Injector Cleaner
· Gunk Fuel Injector Cleaner
Castrol Syntec Power System
· Redline SI-1 · Gunk Gas Treatment
· Monoethanolamine (The monoethanolamine is the worst here. It turns
nylon black on contact.
It is significant to note here that the "best" "detergents" in use today are
similar, strongly alkaline organic solvents). Another use for the current
bunch of organic amine "detergents" is cleaning deposits out of cylinders,
so I hear. I hope this takes the guesswork out of choosing good products.
Greg Davis
Seafoam -injector cleaner -carb cleaner -carbon cleaner -fuel stabilizer -
deicer anti gel treatment -upper cyl lube -frees lifters and rings -dries oil and
fuel ...all in one can! Let's see.. at least 8 things it does.. ok, I could buy
some stabil, and some heet, and some STP fuel treatment and some motor
honey and and and.. Wait a minute.. what was that last thing in the list? All
in one can? Hmmmm.. much easier to measure once in this case and treat
multitudes. Then I have more time to ride, more shelf space for my gloves,
goggles, do-rags.. and maybe someday get to ride with some pretty neat
aliens!