Additive solvents

[Q45tech]

THESE ARE NOT MY THOUGHTS..............posted because someone spent at lot of time and money.

"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 <<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 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.

[goody90q45]

Good article Tech. I know we've discussed using acetone in every tank of gas but has toluene been mentioned? It appears to be on the top of both "good" lists. What do you think would be the advantages of a toluene "shot" with each tankload.

I've got a 10,000 gallon tank of it here at work so my supply is endless. LOL

Thanks in advance for your thoughts.

[Q45tech]

Pump gasoline already contains 10-22% Toluene [and various xylenes] in each gallon! Why you must double the % [of either] to get any real octane gains.

The reason the carrier solvents are used is to ADD BULK in package who would spend $7 for 3/4 of an ounce of detergent and how would you add it to tank without spilling some.

Buy the PURE detergent and premix into a gallon of FRESH gas then add to 22 gal tank. Just like one does for weed whacker/old mowers with 2 stroke oil.

There is something to be said with alternating the detergents if you are sure they are a different formula.

All about cost per gallon of fuel used:

In winter [cold air temp] I can use 89 octane and save 15=17 cents per gallon and make up the detergents externally...........an ounce of BG44k in the tank should equal premium [DETERGENT WISE] that's a $3 saving and less than a dollars worth of BG44k, plus your time in mixing and container safety.

As gasoline prices have increased and the spread between mid and premium increased, it is always worth looking at alternatives so you can HAVE MORE MONEY TO SPEND on MAINTENANCE and REPAIRS.

We recently purchased a case of CRC MAF spray cleaner which is supposed to be non destructive on the newer G35/M45 MAF?

On other boards many newbies are using brake cleaner [which seems ok on 90-96 MAF] but causes problems on the 2002 designs.............lot's of MAF failing but this may be from changes not spray solvents better to be safe than sorry.

[FarFetched]

Aso, toluene is kown to increase octane number.http://www.elektro.com/~audi/audi/toluene.htmlVery interesting info guys!Cheers!

[Infinitiguy19]

Bump because we all know nobody searches anymore and I really hope all this data is still current (true).

[loystock]

I'm wondering why BG44K is not listed, even if the original writeup was done prior to BG formulation change. I switched to Redline SI-1 (from BG44K) as it contains more PAE (Polyether amine) as compared to other cleaners, which are mainly petroleum distillates. Gunk Gas Treatment for one contains @ 70% petroleum distillates and less than 1% PAE. May need to do more research.

[Infinitiguy19]

Well I would be interested in finding out where Dennis got the article.