Been researching prior to doing some Seafoam through the intake on my '88 SPFI, and I just want to know for certain whether or not anyone who has actually used it has experienced problems after using it, or a drop in fuel economy. I've come across a number of things on the internet saying "it works great!", but an equal number saying "don't use it, it's snake oil/damaging/just a gimmick!".

Two completely separate postings on different web forums indicated a drop in fuel economy.

 

Not to be rude, I'm looking for actual accounts, not "well I heard/read/was told this....." type things.

Edited July 13, 201411 yr by SmashedGlass

I've used it in many of my vehicles and have only seen good results. Better throttle response is generally the biggest improvement. I don't pay so much attention to fuel economy so I can't say much about that.

 

I'm no expert, but personally I have not noticed any negative results.

 

The smoke show at the end is always fun too!

 

Note: I think I am remembering correctly that the brake booster line is off to the DS of the intake, which would only clean the DS of the intake and the heads. So you'll want to find a vac line right under the throttle body, so it hits both sides.

Used it annually for 14-15 years on my 87 Brat. Generally right before I change the oil. Short of dumping the whole can in and hydro locking your motor I don't see how it can hurt anything. I have never noticed any significant change in fuel economy, if anything I would guess it got better. This I did notice after the first time I used it, I didn't have to run premium or mid grade any more to prevent spark knock. I think it cleaned carbon out of the combustion chamber restoring the compression ratio closer to stock. That is just a guess though, but an educated guess. I also high dose the bottom of a tank of gas about once a year too. Like 3-5 ozs. per gallon. I actually learned about it's existence on this forum!

Edited July 14, 201411 yr by bratman2

I have used it quite a bit too, I like it. I have run it  in the gas tank of a legacy, I don't know if it effected gas mileage.

I have also at least three times on various old subaru pushrod motors used it like this: I pulled the spark plugs and pored a little in each hole, let it sit for a half hour and then cranked it with out the plugs to clear the cylinders. put the plugs back in and started it, it blows a lot of smoke for a while, which I take to be a good sign. I really like it, I've done this and would do it to any old engine or any engine that has sat for years. never noticed a negative.

I've never used it on my subarus...my current one leaks so much oils that I hardly change the oil lol.  But I have used it for about 150k on my 96 grand cherokee with a 360 in it.  I'm pushing almost 230k on the engine without a rebuild.  Every time I dig into the engine its clean as a whistle.  I attribute it to seafoam with every other oil change.  

The smoke is basically whatever oil is in seafoam burning off. Basically you have a bunch of oil and solvent in the cylinders that can't burn off cleanly in one fire of the cylinder which is why you get the smoke. Its probably is a good idea to do it when the engine is warmed up or at least run it long enough to get the engine up to temperature afterwards so you dont have a bunch of unburnt seafoam laying in the catalytic convertor. I suppose you could foul an oxygen sensor but I don't think thats likely.

 

I'm not sure if there is anything magical about the seafoam itself. Youre just dumping a high concentration of cleaner into the cylinders to loosen up some deposits.

Edited July 14, 201411 yr by stratman977

It is magic, magic in a can, lol! When used like recommended it does work like stated, a cleaner! I think the can says to use on a fully warmed engine, don't have any on hand to read the can right now but that is always how I have used it. Making it stall at the end of a 4 or so oz. feed. Then let set for 10-15 minutes, start and go. Fog them mosquitos out.  The first couple of times I used it on the Brat maybe 15 so years ago the smoke was fairly dark and changed to a lighter color a mile or so down the road. I have never noticed it to be that dark again. This may not be a Subaru but gas engines just the same. Chainsaw my son in law borrowed a year or two ago. Left ethanol fuel in it and could not hardly keep it running. Was a bitch to get started also. I dumbed 2 oz. or so of Seafoam in the tank and by the second tank stalling and amounts of pulls to get started have been reduced by 90%. We have a tiller that I could not keep running without the choke 3/4 of the way on. Dumped 3oz. in a half gal. of gas and by the end of that the choke could be left 1/4 on and it would still run. It will not fix broken systems but will clean them. These are my results and yours may be different.

Edited July 14, 201411 yr by bratman2

Thanks for the honest replies. I'll give it a whirl...........if it does happen to grenade anything, I can always just go out and buy a Subaru made in this century a few months earlier than I planned 

Sorry you are stuck in Florida. My oldest daughter moved back to Denver last Nov. Beautiful state!! Going to Telluride in Sept.

Yes, I miss Colorado quite a bit. Florida is my temporary home for a few years, due to familial responsibilities.