Comparison of cylinder and fuel injection cleaners

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Sirs,

Thank you for having an interest in my work. I've been freely sharing my info with anyone who was interested. I visit your site for help with my car or to try giving advice to others, and I learn a lot. Being able to visit your site for info really helps me understand my car better than I would otherwise. I enjoy your forum a lot and am happy to have my work posted there. I have written everything in what I hope is a clear and interesting format, but feel free to edit as you see fit.

Some background:

First of all, I know that a lot of people who understand cars and can keep theirs in top condition don't believe in using any kind of "mechanic-in-a-can", however I can't help but look at the problems and possible solutions from my own technical point of view. My experience working on cars is limited but I'm great in a laboratory. Chemistry is not only my career, it is also a hobby so I do a lot of experimenting at home. I have a Bachelor of Science degree in chemistry from Northern Illinois University, class of '74. I worked in the petroleum industry for 8 years doing analytical work and research for a major oil company.

What happened:

The reason I did the following comparisons was because I was experiencing problems with my fuel injectors clogging even though I occasionally used products that were supposed to be cleaning them. Initially everything was fine until the day they stopped selling pure gasoline in the Chicago area and switched to gasoline with about 10% alcohol. That's when the trouble began.

I spent months of time and several thousand dollars solving the problems with my fuel injectors and in the process I accumulated notebooks full of data which I have summarized here. I would like to share my info on this forum so that people can make informed decisions when it comes to using the various cleaners available, and also use them wisely.

The damage:

All together, I ended up getting over 8 new fuel injectors, a new gas tank, and had to do some manual cleaning of the fuel lines with rags and brushes and solvents. I found a sticky black "goo" coating everything which was not soluble in organic solvents but was very soluble in water and alcohol. The goo was coating the inside of my gas tank and the alcohol in the gasohol dissolved it and circulated it through the entire fuel system. This is why I had no problems using pure gasoline and had unending problems with the "gasohol". When I saw the nylon "sock" on the gas pickup in the tank it was black and appeared decomposed. I gradually figured out what happened and how to clean it all. It turned out that some of the very products I was relying on to clean the system were what decomposed the nylon sock. I admit that at times I used the cleaners in greater quantities than recommended. It was that old "if a little is good, a lot must be better" mistake. < Big mistake ! >

I began to compare the various OTC cleaners I found in my local stores to see which would dissolve the black goo. To make a long story short, water turned out to be the best solvent and that's not something a mechanic would think of using to clean the fuel system. Since I had all these cleaners available, I next compared their ability to dissolve, or at least move to some extent, the thick, sooty, thermally decomposed material I separated from my oil. I use Mobil 1 5W-30 synthetic oil in my 5.0 liter multi-port fuel injected V8, and I have a large container to put used oil into. I used the stuff that settled to the bottom over the last 2 years as a worst case example of what might build up inside an engine.

As a worst case sample of material which might be found in gasoline I used ordinary tar (tar and gasoilne are just different distillates from the same crude oil source). The brown deposits we find coating carburators, 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, and the injectors too are less prone to clogging.

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 > 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 a gallon of 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 5 to 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.

The tests were done mostly in my kitchen, and mostly at room temp, so there were limits to what I could do. I am no longer set up to use my kitchen as a lab so I cannot repeat any tests. If you are interested in where an untested product would fall on the lists, give me a list (in order) of ingredients from the bottle or from an MSD sheet (with percentages), and I will estimate in what catagory the product will fall.

I obviously could not compare the products under the same conditions found in a running engine, and I wouldn't be surprised if there were changes under those conditions. These results are therefore guidelines to get you started.

TEST RESULTS
RELATIVE EFFICIENCIES AT WHICH VARIOUS CLEANERS WILL DISSOLVE HIGH BOILING RESIDUES (tars) FROM GASOLINE AND CARBONACEOUS (decomposition) 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). They can be used freely in the gas tank. (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 (C)
· 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. (Do not add these to your gas tank unless in small quantities). Also, use them up quickly, do not let them sit for a week. 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. The decomposition products are only soluble in water and alcohol, no common fuel line cleaner will touch them. Without cleaning EVERY part of the fuel system, residual gunk in the lines will plug up brand new injectors in as little as a few minutes. Very expensive. 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. Currently I only use the more corrosive cleaners as sprays into the TB rather than adding them to the gas tank so they can work on intake valve and cylinder deposits but stay out of the fuel system.
 
Jim,

Thanks for posting. This brings up a question that has been on my mind for awhile and that is gasoline quality comparison of the leading brands. I have heard good things about Chevron for example,but they are not in this area. Now, Shell has moved into the State" without their 94 octane
frown.gif
" so we have Shell and Conoco, Sinclair and a few Texaco stations left.
I see on the news in the background that Mobil is on the East Coast,,to get to the point, do you have any information on how to tell what is a better cleaning gasoline and additives in the Brand?
 
Here is some information I have saved for quite some time.
Toluene mixed with 92 Octane Gas should produce
94.2 octane at a 10 percent mix rate
96.4 at 20 percent
98.6 with 30 percent

Xylene
94.5 with 10 percent
97.0 with 20 percent
99.5 with 30 percent
This is usually mixed with Tolune and called a Race Formula

Isopropyl Alcohol and Tertiary Butyl Alcohol
10 percent 94.5 Octane
amounts above this not recommended

Methyl-tertiary-butyl-ether ( MTBE)
10 percent 94.6 octane
20 percent 97.2 octane
30 percent 99.8 octane

This came of the web,I cannot confirm it is safe or really does what those numbers reflect. The Toluene though will clean and give more octane and is cheap from the hardware store. I do not know of any good or bad effects on the catalyst systems or O2 sensors ect

I believe the octane boosters in the can generally reflect points gained in 3 points = the difference between 92 and 92.3 not 95 as suggested in print

I use C12 race gas mixed with 93 Octane unleaded pump gas with real Tetraethyl Lead in my 12.2 Static compression street motor

The Tetraethyl Lead alone raises octane
2-16 points ranging from .6 ounces per gallon of unleaded to 16 ounces per gallon and yep,it causes some build up on the plugs along with some oil that gets blown past the rings when hit hard with the red button
smile.gif
Nice white tail pipes though like the good old days! Smells like the pits of a NHRA or SDBA event as well
cool.gif
 
Thanks, SciGuyJim,

I have found that Coleman lantern fuel or its equivalent is one of the best fuel system solvents and it's fairly mild, since it contains pure white octane (fuel gasoline) and naptha.

Another good fuel system cleaner IMHO, is Schaeffer's Neutra, an ester of
TCP acid and N-butylene alcohol in a thin oil. I have cured a lot of fuel system and "top-end" problems with this stuff. It stinks, but in this case, stinky is good, very good.
 
That explains why the STP tended to give me lower fuel economy after using it in a tank
frown.gif


I've been using the valvoline products successfully however - I will check what they're made of next time I buy a bottle.
 
Sci Guy Jim, thanks for the informative post. I too live in the Chicago area, and we are subjected to the reformulated gasoline. We have three cars, two with high mileage. We have never had a fuel injector/fuel related problem to date. We use Shell premium exclusively, and BP/Amoco occasionally.

The recommendation for Shell came from a coworker years ago, who worked for Shell and raved about their quality control, cleanliness, etc. Additives wasn't even discussed.

The neighbor who always buys the cheapest available gas, always has a fuel related problem.

Is this a quality or brand related issue? I have heard complaint from people in Milwaukee too.

Thanks again for sharing your experience with us.
 
dominic:

i was going through the valvoline msds list the other day, and i noticed that the "synpower" treatments is pretty much kerosene.

(complete fuel system cleaner)
Ingredient(s) CAS Number % (by weight)
KEROSENE 8008-20-6 52.0- 62.0
LT HYDROTREATED PETROLEUM DISTILLATE 64742-47-8 28.0- 38.0
STODDARD SOLVENT 8052-41-3 6.0- 16.0


synpower synthetic gas treatment
Ingredient(s) CAS Number % (by weight)
KEROSENE 8008-20-6 92.0-100.0
GASOLINE PERFORMANCE ADDITIVE 1.0- 8.0


more depressing "synthetic" information can be found here:

Edit out link (it was making the screen too wide, as the URL was too long)

[ October 10, 2002, 08:03 PM: Message edited by: Patman ]
 
sorry about the overly long link. if you are interested, try this instead.

http://msds.ashland.com/ and search for synpower.

i have used this a few times with good (i guess, they weren't bad) results, but for the money you might as well buy marvel mystery oil. i think it's kerosene with some die and smell-good in it.
 
So which (between the two)would be the most user friendly ? and what would be the mix on a 16 gal tank for something around 94-96 with a 91 octane base ?

TIA

SS/LS

quote:

Originally posted by dragboat:
[QB]Here is some information I have saved for quite some time.
Toluene mixed with 92 Octane Gas should produce
94.2 octane at a 10 percent mix rate
96.4 at 20 percent
98.6 with 30 percent

Xylene
94.5 with 10 percent
97.0 with 20 percent
99.5 with 30 percent
This is usually mixed with Tolune and called a Race Formula
I use C12 race gas mixed with 93 Octane unleaded pump gas with real Tetraethyl Lead in my 12.2 Static compression street motor

QB]

 
quote:

Originally posted by dragboat:
Jim,

Thanks for posting. This brings up a question that has been on my mind for awhile and that is gasoline quality comparison of the leading brands. I have heard good things about Chevron for example,but they are not in this area. Now, Shell has moved into the State" without their 94 octane
frown.gif
" so we have Shell and Conoco, Sinclair and a few Texaco stations left.
I see on the news in the background that Mobil is on the East Coast,,to get to the point, do you have any information on how to tell what is a better cleaning gasoline and additives in the Brand?


Sorry, I have no info on gasolines and their additives. I do have a theory though about Shell(?) and their super clean gas. I think they refine it better to remove more of the high boiling (tarry) components. This is the stuff you see coating carburetors and plugging fuel injectors.
 
I don't know the chemical composition of what clogs the injectors, but I have tried half of the products on the top of your list, and the only thing that cleaned the fuel system on my cars was Techron. 3 weeks ago a friend loaned me her Villager with 218,000 miles with a case of STP cleaner with instructions that the only way it runs is with the STP in every tank. It ran with the check engine light, and stalled frequently. As soon as I used up the half tank of gas in it I put in a bottle of Techron and it has run like new for 2 1/2 weeks without a stall or the light. I will return the car next week with the rest of her STP and an empty bottle of Techron.
 
quote:

Originally posted by Bill J.:
The neighbor who always buys the cheapest available gas, always has a fuel related problem.

Is this a quality or brand related issue? I have heard complaint from people in Milwaukee too.

Thanks again for sharing your experience with us.


I don't have proof, but a lot of people think most gasolines are very similar, if not the same. They talk about the different company trucks filling up at the same fuel depot. I think the biggest differences come when each company adds its own secret blend of additives to the gas. I've heard that name brands will have better additives which can, for example, keep fuel injectors cleaner, whereas no-name brands only add the minimum that they can get away with.
 
quote:

Originally posted by widman:
I don't know the chemical composition of what clogs the injectors, but I have tried half of the products on the top of your list, and the only thing that cleaned the fuel system on my cars was Techron.

Gasoline is a mixture of thousands of different chemicals, some low boiling, and some high boiling. Higher octane gasolines are more expensive because they are processed a little differently so that they have more benzine, toluene, and xylene in them. Refineries are always on the lookout for ways to increase these concentrations.

Injectors are clogged by the high boiling components in the gas. If you saw these, they'd look black and smell like tar. After the engine is shut down and the injectors get heat soaked, the lighter components in the gas in the injector tip will vaporize and leave behind the heavy, tarry compounds. The high heat can further cause these to oxidize and polymerize so they don't get washed away easily.
These things don't all get removed during gasoline refining because of the huge number of different compounds in the gas. It's just the way the chemistry works, there is no sharp temp at which gas distills.
 
Techron was mentioned in some posts. A lot of people have good results with this product. I've never heard if it, or any other cleaner, works differently at engine temps vs room temp. I would expect some differences. My lab was my kitchen and there was only so much I could do.
 
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