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.
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.