[N1ckB]

Hi everyone!! I just joined this forum today since I an a new owner of a 1982 380sl here in Southern California.

I did a search on this forum on "seafoam" and I'm surprised that nothing came up. Has anyone used this on their 380sl and would there be any adverse effects I should be aware of.

This car had been sitting for about two years now and after a lot of tune up care I've done it still has a bit if a rough idle and puttering during acceleration.


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[dugald]

You must be searching wrong.
I found dozens of posts.

 

[Musikmann]

My only hesitation is that MB has never endorsed it as a fuel system additive whereas they do recommend their own labeled product and Chevron Techron Concentrate. However, a member here for whom I have tremendous respect loves it.

 

[reno4u2]

As did I. Is this how you're doing it?

 

[AndRose]

Hi everyone!! I just joined this forum today since I an a new owner of a 1982 380sl here in Southern California.

I did a search on this forum on "seafoam" and I'm surprised that nothing came up. Has anyone used this on their 380sl and would there be any adverse effects I should be aware of.

This car had been sitting for about two years now and after a lot of tune up care I've done it still has a bit if a rough idle and puttering during acceleration.


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Welcome. New here as well. I just Seafoamed an 87 560SL, mainly because it had been sitting for about 9 months. It's essentially a solvent (Naptha), lubricator (Pale Oil) and alcohol (old method of stabilizing fuel and octane booster). I've always had noticeable results on older cars…100K+ miles. A little buildup in the top-end can create small ticks that would lead you to think it's bad valve guides or lifters, when it's really just gunk throwing the tolerances off (it doesn't take much)…especially if the car has been sitting and the fuel has gone south.

On this 560, it eliminated some minor ticks and clicks and brightened it up quite noticeably in short order. I wouldn't put it in the crankcase to save my life, but half in the intake and half in the gas has always treated me well.

Just be slow with it as it burns hot and if your CIS is running at all rich, this stuff can heat your cat up pretty quickly if you have one. It's essentially a very high octane solution.

Also, I would add it (very slowly) directly to the intake metering plate to ensure it gets to all cylinders. The vacuum line method doesn't distribute it very evenly. Just dribble it incrementally…you'll hear the engine stumble and pick back up. Too fast and you'll hydrolock and that'll be game over.

Last thing – if you go nice and slow with it, you may not see much smoke, which is fine. The billowing white clouds you see on YouTube is just the sea foam burning off…not carbon…which is why some people chalk it up to snake oil.

With all of that, I'd do it once and be done with it. Moving forward, stick to Techron…it should be all you need.

Also, two years is a very long time. I'd guess that your fuel delivery isn't operating as it should. Also, in my case the ignition setup was all original…wires, cap, rotor, coil etc. It'd be worth swapping that all out. Especially the coil…even the slightest output issues can create some marked performance issues.

Let me know if you notice a difference!

 

[N1ckB]

Thank you all for the quick responses. The search I tried is through the iPhone app so there may be something quirky there.

As for the seafoam, I was thinking through the vacuum hose but I'm not sure which one to use?? The main issue that I have with my car is that I'm getting a lot of black soot coming out of my exhaust when I first start it up and give it some good revs. So I know it's a sign of richness but I have new copper core Bosch spark plugs, new Bosch spark plug wires, cap and rotor, new tank strainer, fuel filter, checked and fixed a lot if vacuum hoses and connections.

Any help would be appreciated!!


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[isthisdave]

.



Typically the brake booster vacuum line is used to dose the intake/valves/upper cylinder.

That method does not access the fuel supply/injection components, add to the tank to do that.

Beware if you choose to use the vacuum line, it is a stiff plastic and you WILL break the inline check valve if you handle the line too much.

 

[AndRose]

I had the same problem. I'm assuming with all the fuel work that the gas in it is new.

No doubt from 2 years of sitting the fuel delivery system has gunk all through it…especially up in your CIS. By soot, I'm imagining the kind you see blasted on the ground along with some black smoke that clears up after a minute.

I'd go ahead and split the Seafoam 1/2 in the tank (make sure it's a full tank) and the other half into the intake. Manifold is the best bet for even distribution…vacuum will load it up at the back end.

Other than that, a couple tanks of fuel, Techron and time running the engine will help clear some of this up hopefully.

You can tweak the CIS a little to lean it out but just have to be careful.

 

[N1ckB]

Yes the fuel is new now. How do I put the seafoam in the intake???

 

[cwmoser]

FYI, I used some Seafoam Trans Tune in my transmission in my 1986 560SL
and it took out about all the "thump" when shifting into Reverse. I put in
1/2 bottle, drove for a while, noted that the "thump" would come and go, then
put in the remaining part of the bottle, and now the "thump" has largely gone away.

Carl

 

[AndRose]

Pull the top off the air cleaner and that's your intake…the big disc is the airflow metering plate. Just dribble the sea foam over the top of this plate with the engine running and it'll draw it in. Then turn the engine off and let it sit for a bit…5 minutes or so. Then start it back up and run some revs through it and take it for a spin, or simply run it stationary for a bit until you've burned it all off.

Dump the rest into your tank. Because mine sat, I just let it idle for long periods of time while I worked on other things, and would run it through some paces…holding at 2500, some higher revs, holding it at 3500 etc., just to run some fuel through the system without the risk of having an issue out on the road. Eventually the soot disappeared, the smoke disappeared and the engine settled into a much better state than when I had started.

 

[N1ckB]

How much would you "dribble"? Is that half the bottle? And you would do it at idle??

I just want to do it right!! Thanks!!!!

 

[AndRose]

I'd do it at idle. Half of the bottle.

Dribble, not a pour – so think a tablespoon at a time. You'll hear/see/feel the engine lag a little after each tablespoon…when it picks back up, do it again until half of the bottle is gone.

 

[N1ckB]

Ok, great. I'll try that and get back with the results!!

 

[1Blue]

I have a small refillable spay bottle I bought at the grocery store. So I don't by accident pour or spill it. On my Isuzu, the EGR tube can get clogged, so I squirt Seafoam down it. Like others I add it to my gas. I also have added it to my oil right before changing, then do a short errand and drain. My Isuzu has no valve ticks or pings. Runs great.

I've only added it to my gas in my 560... On a side note, for a vehicle that has sat for a long period, after changing the fuel filter, etc. I would drive the car for six months, or if you hear your fuel pump whir, then change your fuel filter again right away. A clogged fuel filter will cause your fuel pump to work harder and wear out sooner. Pouring solvents into your tank could be dissolving crud in your tank which then is deposited in your fuel filter. Many years ago I was coming home from college in a 72 Chevy Vega. (I know, worst engine ever, it was a gift) It was Christmas and it started acting up. Barely made it home. I tracked it down to a clogged fuel filter. Since then I routinely replace them. I take a black Sharpie and write the date on it.