Seafoam

[Elessee]

Preparing for my current major tuneup, I bought some Seafoam. I'm not a fan of any "additives" but after reading up on it, it seems like a good way to loosen any crankcase carbon / varnish deposits before I change the oil and oil filter.

This Seafoam stuff appears to be a light oil with a lot of detergents. Company webpages say it will act as a diesel fuel by itself, but will not run a gasoline engine without some additional portion of gasoline.

Anyway, I had the car warmed up and idling, and removed the oil filler cap, inserted a long thin funnel and proceeded to pour about 6 ounces (1.5 oz per quart oil) into the filler.
The engine almost stalled. Almost. It hunted up and down for about 10 cycles and then calmed down. Weird.

I was just thinking that some had been sucked into the crankcase vent hose, which connects directly to the throttle body, and upset idle mixture.. but when I double checked, the funnel I used reached way down into the valve cover.
No way could any of that Seafoam travel backwards and up into the vent hose... yes Way?

So, I want to know how did pouring Seafoam directly onto a few of the rocker arms / lifters somehow affect idle? Like.. Might these valve stem clearances be so sloppy that it got sucked into the combustion chambers?
Are normal stem clearances wide enough to expect some lightweight oil would be sucked in?

 

[Elessee]

Take a whiff of that SeaFoam and it's gotta be way over 100 proof (50%) methanol. I think that's why pouring some into the rocker arm cover affected idle mixture. Some of the vapor alone was sucked past the valve stems, and into the combustion chambers.

I did the SeaFoam intake manifold treatment and quite a bit of smoke came out the tail pipe. But I am now dubious as to what that smoke means as far as cleaning carbon deposits.
Supposedly, SeaFoam dissolves the varnish from gasoline that glues carbon particles together. When the varnish dissolves, carbon is free to move.

Due to another project (heater core) I removed the throttle plate and EGR spacer. If any carbon was removed, I don't see how or where. There is (was) not one clean spot anywhere.. not in these parts and not inside the manifold. There is a couple milliliters (CCs) of liquid oil sitting on the floor of the manifold. I suspect it is part of the liquid that was sprayed in. My guess is that air speed at this little depression is probably near zero, so the puddle just stays there.
But maybe it's oil vapor condensing and collecting from crankcase ventilation.

I've since cleaned up the throttle plate and spacer using regular old B-12 Chemtool at 1/3 the price of SeaFoam @ $9 for 16oz.
B-12 works real fast dissolving varnish and softens the carbon deposits almost on contact, so they can be brushed away. No doubt due to the toluene content..
SeaFoam, otoh, doesn't have much effect. It doesn't have anywhere near the same solvent power.. Hardly touches crusty carbon.

I know SeaFoam's been around for like a century, people swear by it, and have had all sorts of fantastic results. My results might not be typical.
Figuring it contains 50% (8 oz) methanol costing $4.50 (half of $9), I'm paying $72 a gallon for the methanol in there..

Anybody know why methanol would clean up an engine? I know it absorbs / mixes with any water in the gasoline and allows it to "burn".. they even advertize that side effect on the bottle.. but does the methanol in there have other benefits?