How to: Seafoam Your 4.0 SOHC

ok, so I've seen lots of threads explaining how to do this, and there are SO many ways, and alot of people are still confused. so I'm just going to give the top three that I think are the best, together for everyone. Remember to to do this away from the public, or your going to get a lot of WTF? looks from people lol.


(1) Via the IAC vacum hose - this is my favorite because I (and a lot of other members) feel it completely coats your entire motor and doesn't require a lot of work, IMO.

(this is easier with 2 people) start the engine and hold the RPM's at like 1500 and pour the seafoam into the top of the t joint. (a funnel helps here)(pour it kind of fast paced, but not enough to drown the motor) once all the fluid is consumed turn off the engine and leave it for like 20 min.


come back, and start it, you will prolly need to hold the gas down a bit when you start it. when you do, rev it a few times, then took it for a drive and held it to the floor for a bit.

(2) Via the Brake Booster vacuum hose - another popular option. i'm not really a fan of this method because a lot of people feel it doesn't spread evenly. i used this method the first few times, its the easiest.

basically, unhook the hose from the booster, start your engine and hold rpm at like 1500 then put the hose into your container of Seafoam and let it suck it up, then turn your engine off right away. leave for like 20 min then come back.


come back, and start it, you will prolly need to hold the gas down a bit when you start it. when you do, rev it a few times to like 3000, then took it for a drive and held it to the floor for a bit.

(3) PVC Valve Vacuum Hoses - haven't tried this yet, but it requires a bit of work, and appears to also give an even coat.

you need to take off the hoses on the rear of your intake, add t joints on each side, and join them in the middle (even length) with another t joint, then you can pour the Seafoam in the middle, and feed both. (remember to plug the hole after.

come back, and start it, you will probably need to hold the gas down a bit when you start it. when you do, rev it a few times, then took it for a drive and held it to the floor for a bit.





And there you have it! the top 3 ways to Seamfoam your 4.0 SOHC motor with the liquid seafoam can. i like (1) the best. and i have noticed huge improvements with this product.

any comments or questions or problems?? (Sticky? )

Too bad your photo links didn't work. Another reason to get an Elite membership and use the file storage here.

I had a SOHC for several years and much preferred the IAC method. I wish there was an equally simple method for the 302.

sorry bout that, fixed the pictures.

vote for sticky??

rev to 5000 rpm!? your kidding, right?

lol eh, i would never do that if it was cold motor, i always go for a long drive and make sure everything is warmed up. i dont see a problem with doing that if its warm. im not going over 5K tho. never max it out and its reved up to w/e quickly not like i hold it at 5K lol....

im sure alot of people would say thats bad tho..

5000 rpm under no load is kinda bad to how ever. even if you are just blipin it.

ok well i changed it, i dident see a problem with it, i would figured it wouldent be that hard on the motor with no load. dont want someone blowing up their motor by accident lol :O

ok i have one question in method 1 i was looking at the picture i only have one hose connecting to the intake tube it is the hard plastic one do i use that one

if you can tell if it goes to the IAS then i would say yes. if the area around the MAF looks like my picture, chances are its the same. i dont know if the engine design has changed from 97 to 01, im sure it has.

can someone help him? i dont know what an 01 engine bay looks like.

Equnoxe said:

if you can tell if it goes to the IAS then i would say yes.

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what is IAS

celly said:

Too bad your photo links didn't work. Another reason to get an Elite membership and use the file storage here. .

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Work fine for me.

ramren16 said:

what is IAS

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sorry meant IAC (Idle Air Controler)

Ias is from my stupid videogames lol :O

this is what it looks like, just follow the pipes, it should be on the top center of your motor, it may be covered by that black plastic protector if you haven't already removed it.

the pics work now, i fixed them, messed up the format or w/e when i was typing

aldive said:

Work fine for me.

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Equnoxe said:

sorry bout that, fixed the pictures.

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Thanks for that Al. That what "fixed" means.

i have no tubes going to the iac the iac is bolted to the throttle body and a wireing harness plugged in the back of it the one tube goes into the engine (crank breather tube i believe)

Run similar stuff through our boat to winterize it, to coat the cylinders with a little oil. Never done to a car or truck before though since its started almost every day. On their website it says to pure 1/3 into the gas tank to clean all that stuff, 1/3 into the crankcase, and 1/3 like you all have described before. (All 1/3's or from a full pint) Anyways you all do it in those three spots and does it really do anything?

im sorry ramrem i dont know how to help you, anyone here got anything??

ive noticed quite a big change actually, engine runs smoother, acceleration has alot more Umph to it now, and my fuel economy has gone up , just from my personal experience, im happy with it.

ramren16 said:

i have no tubes going to the iac the iac is bolted to the throttle body and a wireing harness plugged in the back of it the one tube goes into the engine (crank breather tube i believe)

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The '01 Sport might be set up differently. If I recall, the SOHC in the '01+ Sport and Sport Trac have a slightly different configuration under the hood. I know that certain mods (like air intakes) for 95-01 Explorers don't work on '01 Sports and Sport Tracs. For many mods, 2nd generation means '95-'01 (4 door) and '95-00 (2 door, i.e. Sport).

I read you have to change your oil when you use seafoam, is this true?

I never have.

maxjivi05 said:

I read you have to change your oil when you use seafoam, is this true?

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Only if you're putting it on your oil. I never add ANYTHING to my oil.