http://www.delica.ca/forum/my-acetone-r ... -8758.html
http://www.delica.ca/forum/seafoam-discussion-9722.html
http://www.delica.ca/forum/i-need-your- ... 12046.html
Lately I've been looking more at cleaning my engine guts, inside and out, and at Seafoam in particular. I do a lot of short-trip city driving that can be really hard on diesels like ours.
So I did some reading & tinkering, and here is a great long post on what I found out about helping to keep your engine running cleanly. Enjoy!
Disclaimer: I am not a Chemical Engineer, I just like to fiddle around with stuff like this and try to understand what is going on. Follow my advice at your own risk...
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Executive Summary:
For a less messy, more hassle-free way to clean your injectors/cylinder-interiors than Seafoam in the fuel filter, consider buying some ultra-pure Isopropyl Alcohol (IPA) and use it in your fuel tank instead of Seafoam. It's cheaper and depending on your engine condition, it might just do the job you need.
Do use Seafoam in your crankcase before you change the oil/filter to clean out deposits inside the engine - it does a great job. But do it cold and do it gently.
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A Bit of Chemistry first..
According to the manufacturer, Seafoam is 4 parts #1 diesel fuel, 2 parts naphtha (Coleman fuel) and 1 part Isopropyl (Rubbing) alcohol (IPA).
Diesel fuel and naphtha are distilled from the same dead dinosaurs as crankcase oil, gasoline, and other petrochemicals. Chemically, it is made up of Carbon and Hydrogen atoms.
Alcohol is completely different stuff. Along with the Carbon and Hydrogen, it contains Oxygen as well (more on that later).
One more thing to note - in general, substances prefer to dissolve other things that are similar to themselves. For example, if you get grease on your cotton shirt, you're better off wiping it with Coleman fuel rather than alcohol before washing it.
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Injectors and cylinders:
From what I have read, most performance-robbing deposits in cylinders and on injector tips (i.e. surfaces where **BOOM** happens) are carbon leftover from the fuel. In addition to clogging the injector tips, they cause pre-ignition hotspots and can cause localized points where engine oil can slip by the rings into the cylinders and burn.
This stuff needs to be burned off, not dissolved away. To do that, you need Oxygen to help turn the Carbon into Carbon Dioxide gas (CO2) and out the tailpipe.
It is my belief, but I can not prove it, that the 15% alcohol in the Seafoam is what is actually cleaning your cylinders and injector tips by helping burn off this carbon with the Oxygen it brings along to the party; the other 85% is in this case there to carry the alcohol to the cylinder and allow the engine to run without stalling.
Now Seafoam is trying to sell a single product to as many people as they can, to do as many jobs as they can claim (Jack-of-all-trades), and certainly it seemed to help last time I used it. Fair enough, but I'm spending over $10 for less than a litre of something that is more than half plain-ol' diesel fuel. Grrr...
So being a cheap and lazy bugger, and not wanting the mess of trying to fill up my fuel filter, I thought I'd try a little experiment.
The Rubbing Alcohol you buy at the drugstore is cut to a greater or lesser degree with water. Even the stuff labelled 99% I have heard rumours that it ain't necessarily so.
However, there are lots of electronics shops/industrial chemical supply shops that will sell "Anhydrous (99.954% Pure) IPA" for around $20 for a 4 litre jug. (I bought mine at MRO Electronics on Boundary Rd. in Vancouver).
On my last road trip, I ran my tank down until the fuel light was on steady. At this point, I have around 15L of fuel left.
I pulled over and added 750 ml (3 cups) of IPA - cost around $4 - and happily drove another 90 kms or so down the highway before filling up as usual. This pushed through as much IPA as six cans of Seafoam, while still keeping the overall fuel at 95% regular diesel. IPA is a pretty mild solvent compared to its harsher cousins (like acetone), and I have read studies on diesels running fine at 15% IPA (equivalent to pure Seafoam) for long periods of time without severe deterioration of internals from the alcohol.
The net result for me was noticably less black smoke on hard acceleration afterwards; the same effect I saw when I had used Seafoam in my fuel many months ago. Yay!
Now if your fuel lines are clogged up with heavy greasy deposits of some kind, the IPA treatment will not help. But I suspect for most people this is not the case, since regular diesel fuel is thin enough to dissolve away most heavier types of hydrocarbons. Certainly it seems that way for me.
Now onto the crankcase...
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Seafoam in the crankcase:
This is where Seafoam really comes into its own. Since it is 85% lightweight, distilled petrochemicals, it should do a great job at dissolving greasy goo left behind in a crankcase. Two things to think about if you give it a try:
- if you want to give the 15% alcohol a shot at dissolving any non-grease-related dirt inside the engine, you need to pour the Seafoam into a cold engine. IPA boils off at 82 degC, so by the time the engine is close to normal operating tempertaure, the IPA will be long gone.
- I know there have been posts about giving your vehicle a good run down the highway to give the Seafoam a chance to circulate, but I'd be careful about putting the engine under much of a load. The Seafoam is working by basically thinning out your engine oil and while this makes it a better solvent, I think it really degrades the lubricating properties.
If you've never done it before, when you drain the oil (very important after a Seafoam clean), the oil is like water - the blackest dirtiest water ever, to be sure, but *very* thin and runny.
I spent about 20 minutes very gently running on flat roads with a very light foot at moderate revs to get the oil moving while not putting too much stress on the components.
After a drain and new oil/filter, it idles remarkably quieter, especially when it is stone cold. No more bag-o-wrenches noise. BIG difference.
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So that's about it. Anybody got anything to add - fire away, but I'm making this part of my PM schedule. With fuel costing as much as it does, it doesn't take much of a performance improvement for these little tweaks to more than pay for themselves.
PS: The two-stroke oil still seems to be helping my winter fuel consumption...
, I am actually quite familiar with the Howes line of fuel conditioners 
