What does The Garage think about Seafoam?


Aug 22, 2004
I've been reading some info about this, bunch of people saying it's good to use to clean up carbon, fuel injectors, crank case, etc. You're basically supposed to put it in everything except the radiator.

I was wondering what the Garage thought about this stuff. I'm doing a tuneup on my Freecar Altima, and it has 171+ thousand miles on it. Can Seafoam damage an engine, especially a high-mileage one?

angry hampster

Diamond Member
Dec 15, 2007
Putting it in the crankcase isn't worth much unless you've gone way too long wihtout oil changes. Running it through the vacuum lines to the intake does wonders for some motors. On my old Jeep, it smoothed out the idle beautifully.

Seafoam won't damaage your engine. Will give you a sweet smoke show though.


Jan 2, 2000
It's snake oil, for the most part. You can find some anecdotal evidence of it helping this problem or that problem, but that's it.

I'd never pour it in my crank case. I'll concede it's possible it could make some difference by using it in a carburetor or fuel system, but I wouldn't put it in my gas tank, either.

Basically, for whatever they tell you it can be used for, it's either an outright snake oil claim and not necessary, or there are better products for the different areas of the car.

natto fire

Diamond Member
Jan 4, 2000
I subscribe to the notion that things like this are exaggerated, placebo, harmful, or a combination of the three.

There are rare circumstances where pour in additives are great, and I have experienced them first hand although i was told otherwise. Both involved an oil treatment that helped stop oil consumption on my '84 Cressida with worn valve seals, and a '92 Jeep that was leaking from the rear main seal.

Neither had much longevity proof, because I junked the Cressida a few thousand miles after treatment, and sold the Jeep shortly after. Both worked in the immediate. I'm assuming the Jeep is still going because that straight 6 engine has rightfully earned a reputation of being indestructible. The Cressida had a good straight 6 as well, but lacked the torque of the Jeep.


Diamond Member
Oct 18, 2004
i've used it... good smoke show...

people claim that white smoke is carbon burning... i have a feeling it might just be seafoam burning.

Dealerships do similiar stuff with BG 44k and BG intake clean, either at the fuel rail or throttle body.

The stuff is out there. Plenty of it but who knows really what works on what. Not many independent places/people have done before and afters.

I've seen 3-4 guys post up about http://www.auto-rx.com/ on forums that i visit, pictures weren't as clean as the photos there but there was diffrences. But look at it this way, people who do this stuff have general know-how and well most likely their engines are cleaner then others.

I still think all are snake oil but i do buy them from time to time when they are on sale. Lucas mainly for the buy one get one free bottles.


Diamond Member
Oct 13, 1999
It will clean the carbon off of pistons/valves if feed through a vacuum line but then so will water


Apr 9, 2000
back in ~06, I had a 93 Honda Accord and an 03 Pontiac Montana.

The accord was a beater with 175k, the Montana had ~40k.

I ran seafoam in the vacuum lines of both vehicles. The accord definitely benefited, smoother idle and acceleration. It also had one hell of a smoke show.

The Montana had no noticeable difference, and also didn't really put out much smoke.

I always wrote it off as a much more efficient Catalytic Converter on the Pontiac....

Now the Pontiac has 105k miles. Thinking I might try it again this weekend to see how much smoke I get :)


No Lifer
Jul 3, 2003
Never used it...

I think it's a big waste of money and would never put it in any vehicle I own.


Golden Member
Oct 16, 1999
It's basically a solvent, so if something is gummed up or sticking, it will loosen it up. The thing is, on modern engines, using modern oil, and that are in daily use, that's really not a problem. If you've had a '64 Chevy sitting in a garage for 15 years, Seafoam might work wonders. On a '98 Honda with 200,000 miles, it'll make smoke, but that's about it. If you want to knock off carbon, do some full throttle runs, preferably up a long hill. You'll knock the carbon loose.


Senior member
Jul 9, 2000
Does seafoam work, YES. will it work for you, Possibly.

Its main function is getting the carbon out of an engine and it works great on 2 strokes and old 4 strokes that have been around for years or abused. It needs to be put in the intake AND crankcase. In the Intake it will clean up the combustion chambers and valves along with the top piston ring. It NEEDS to go in the crankcase to clean off the oiling rings if you are having an oil consumption problem. Don't run it too long in the crankcase, just long enough to warm the engine up to get it circulated, let is sit for 1/2hour then change the oil immediately. Ive had great luck with using it on old 2 stroke outboards fir restoring compression and on lawnmower engines that used oil. Even my old Explorer saw a significant drop in oil usage as it went from 1qt every 500 miles to 1qt every 1500 miles. That said, water mist in the intake will do just as good on that end but seafoam does wonders in a crank case. NEVER use the water method on a 2 stroke though, it will wipe the oil off the bearings.


Golden Member
Aug 4, 2004
I've seen 3-4 guys post up about http://www.auto-rx.com/ on forums that i visit, pictures weren't as clean as the photos there but there was diffrences. But look at it this way, people who do this stuff have general know-how and well most likely their engines are cleaner then others.

I still think all are snake oil but i do buy them from time to time when they are on sale. Lucas mainly for the buy one get one free bottles.

I did an Auto-Rx treatment on my 98 Passat when I first bought it (2004). The 1.8T in the Passat is known for oil sludging issues due to a small crank case (3.8Qt with the OEM small filter) and an oil return line about 2.5" away from the turbo.

After the first 2k mile stage, I had my oil changed at a jiffy lube type place, and the guy commented on how much sludge was dripping out of the crank.

I changed it again at 3k like you're supposed to, and noticed some gunk but nothing crazy.

Mainly I did it for peace of mind, since I didn't have many service records from the previous owner, and he likely wasn't using the recommended synthetic.

As for Seafoam, I've done it a few times to the same car, half a can in the tank the other half sucked in through a vacuum line. The car felt smoother, though it could have been a placebo affect. The smoke show however, was worth it. I covered my entire block in a thick blanket of white smoke.


Golden Member
Dec 30, 2003
I've used it several times in a couple vehicles. The first time I used it I did notice an improvement, after that I can't say as much. My saturn has been plagued with a surging acceleration since I bought it 120k miles ago and I've tried several remedies suggested by saturnfans.com yet the problem persists. The first can of seafoam was the only remedy that actually did make the problem go away for a few weeks.


Diamond Member
Jun 22, 2003
I've considered using it on my 87 Caprice for a while now. Having never done it before I am a little hesitant to simply unplug a vacuum line and put it in through there. It would probably work wonders though from what I've heard.


Oct 9, 1999
It works well on older vehicles. I have used it on over 10 cars for friends and family and it does help, most told me they noticed a differnce and most of them had no idea i used it. Helped smooth out the idle and acceleration on my 88 CRX, couldnt believe the smoke that created.

I wouldnt bother on anything with under 100,000 miles on it though you probably wont need it.


Dec 14, 2000
ive used it on lawnmowers, jetskis, string trimmers, cars, trucks, etc. Never had a problem with it, but have noticed good results on mostly the 2 strokes with the hesitation going away, strong acceleration coming back, overall better idle, etc.

Its not snake oil and really does work.


Junior Member
Nov 26, 2019
I need some help plz .. my local advanced auto, suggested me try sea foam..I don’t like using additives, I put it in my gas tank. I have 2001 Dodge Grand Caravan been having rough idle n misfires, they said they use it in their car and never had issues.. I have 17600 miles..So it didn’t help but it smoking and asked them why .....the auto associate said don’t know why... the thing is it comes n go on smoking depends on my van and weather . How long before it stops smoking? bcz it been a good 3-4 months it worrying me. I called sea foam they don’t have clue and said get with mechanic.....I just want make sure my engine not mess up..I should’ve passed on it.. I trusting the staff..normally, I’ve only use fuel injectors or gas treatments that it.. I appreciate any help thank you!


Elite Member
Super Moderator
Jan 31, 2000
Seafoam customer service is right, you need to have your car looked at by a mechanic. Your car should not be smoking after 3-4 months. Something is definitely wrong.


Jun 30, 2004
I was seeking a means of eliminating the hesitation and RPM drop below the idle spec on my old Trooper. The symptom seemed indicative of a dirty EGR valve.

You can take the EGR valve off the car, replacing the gasket when restoring it, and clean it with carb cleaner, (maybe) Seafoam, or a specialized cleaner. Bardahl makes a product that supposedly cleans the EGR "in place" without removal, and other YouTube "How To" videos and forums suggested using Seafoam in exactly the same way as the Bardahl product. Wynn's makes a similar product. I deferred the attempt, since the symptom was occasional and minor.

Instead, I started buying the small $5 bottles of Lucas Fuel-Injector cleaner to add with a fresh tank of gasoline. Of course, the manufacturer wants you to buy more and use more, but I followed their advice to add a bottle of the stuff to each successive tank of fuel, and continued to use it by the half-bottle.

Whether it was the EGR valve or the fuel injectors or something else, the symptoms disappeared. I'm looking forward to my next smog-test in January to see if there's improvement in the HC and NOx ratings, since I've been using Premium gasoline with the Lucas for the last year. Some sources say that using Premium gas will renew a catalytic converter -- which is supposed to keep HC and NOx emissions low.

That sucker sure runs well now, after a year of Premium plus Lucas.

I am still sparing and cautious about additives in general. I have a small oil leak at the rear main seal of the engine, and the Blue Devil product "Main Sealer" works. They insist the use of their product is permanent, and you shouldn't need to add it again with an oil change.

My transmission also leaks a little from the main seal in the bell housing. We torqued the tranny-attachment bolts to factory spec, and the leak attenuated, but didn't go away altogether. I can't lose enough Dexron to justify adding an entire 9 oz bottle of Blue Devil tranny sealer. I might find about a thimble-full of tranny fluid in the drop pan after a month's time. So I'm not going to do more with it for the time being.


Diamond Member
Jan 28, 2000
I feel like its a holdover from carburated cars or early EFI. I don't feel like it has much place in a modern engine. I'd be more worried about damaging a seal etc with it than any good it would possibly do.


Jun 30, 2004
I feel like its a holdover from carburated cars or early EFI. I don't feel like it has much place in a modern engine. I'd be more worried about damaging a seal etc with it than any good it would possibly do.
Like I said, I've been cautious. Blue Devil products have decent ratings among customer reviews, but here and there you'll find cases where the user overfilled the tranny, or the seals were swollen so badly that the tranny started leaking like a sieve -- opposite the intended effect.

The engine Main Sealer and a similar formulation -- both Blue Devil products -- seem to perform more reliably. I personally attest to it. But I avoid products which remove "varnish" from the engine. It could be asking for trouble.

The Trooper and its engine are 188,000 miles and 25 years old. I'll go 3,000 miles, and never have to top up the oil. At one point, I'd go 3,000 miles and the oil would be a half quart (of five) low -- but this was apparently due to the leaky rear main seal. For the additives mentioned here, I've never used the full bottle.

I figure if you have a 25 year old vehicle with smog test results better than it had at 6 years old, it's probably worth it to change the oil every 2,500 miles even if using Full Synthetic. Baby that Sucker, I say! If an engine is going bad, "getting tired", etc. -- you would notice things gradually, like worsening smog-tests, burning oil, compression tests falling short. If none of that is happening at 188,000 miles, getting to 230,000 or beyond seems like a good bet.

I still wonder about my head gaskets. In 2009, the water pump froze, timing belt broke, radiator was damaged. We thought there might be damage to the engine, but "Nope." I was told that if damage was done to the head gaskets, it might show in a month's time, but "Nope." That was at least 30,000 miles ago. So like I said, it seems like a good bet for keeping the Trooper, paying for the peripherals and maintenance, and saving my money.

I might "try" additives, as I have with the Main Sealer or fuel-injector cleaner. The Lucas cleaner is harmless. But otherwise, why screw up a good thing?


Diamond Member
Aug 11, 2001
It can help clean the intake out but at the same time you should never add it before a MAF sensor as it can cause it to get fouled.

It has no purpose in fuel compared to better treatments like Techron or similar. It has no purpose in oil, even if you are a believer in doing oil flushes (there are passionate arguments on both sides for and against it) compared to a purpose specific product or just using diesel. Generally, you're better off just changing oil more often with a full synthetic and letting that gradually clean out sludge.

Keep in mind that the white smoke coming out the exhaust if put in the intake or fuel, inevitably causes deposits on your cat and o2 sensors. Any goop it cleans out upstream may also deposit there. It should be used minimally if at all as preventative maintenance, instead is more of a last ditch cleaning effort before replacing parts.
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