Seafoam and other additives...

[TBFK]

Hello Legacy Central! I'm not sure if i'm posting this question in the right place, but I was wondering if any of those additives they sell at the parts store actually make a difference?? For example "Seafoam" or "STP".....

I've tried a couple, but never really noticed any difference in MPG, Performance, or anything like that.

And, does anyone recommend anything?

Thank you!

[BoostedSubie]

I've used Seafoam for cleaning the fuel systems in previous cars and seems to help. A lot of people swear by it too. Other than that, i've never used anything but injector cleaner.

[Rubasu]

are we talking about oil additives or fuel?

Oh can u help me i cant get my gun to work any more with duck hunt!

[TurnNburn]

I like using seafoam for verious reasons in my car. I like that it is versitile and goes into multiple places which is why i pick it more then others.

OIL-Before i do an oil change i will pour in like a 1/3 of bottle and run it in there for like 100 miles and then change my oil. This was especially helpful in cleaning up my hydraulic lash adjusters which would make an annoying clicking noise while running. I changed my oil 3 times within 1000 miles and used a 1/3 of seafoam everytime. Even though the oil was still pretty new, it would still come out nasty after only a few hundred miles. Each time i did this the oil got better until it stayed the normal light honey color. The guy who had this car before me must have not liked it very much . Right after i fiilled it up the 4th time the clicking noise went away and i havent heard anything from them in 5k miles. I just want to say that the alcohol in seafoam is really bad for the rubber parts in your car over time, so i would not recomend using them for extended periods of time if avoidable but i will still use it. Everything in moderation right?

FUEL-My fuel system is in pretty good condition. No sediment in the tank, good gas, and new filter. Iv never noticed a difference in performance when adding it into the fuel but thats just me. Im not sure exactly what it is supposed to be removing from the injectors besides " build up and gunk", which im not sure what they mean by that. But if you did have contaminents in your fuel like rust or something then it might help.

VACUUM-The 3rd place to put it is into a vacuum line while your car is running which cleans your intake manifold and your valves. Now this is one people get kind of squimish about because your basically pouring 4-5 ounces of liquid into your engine, which kind of goes against what common knowledge dictates as good ie. hydro lock=bad. This is also the only place i noticed any change in how my car performed. Cleaning the valves, pcv lines, back side of the throttle body, and the intake manifold really improved my throttle response and my idle. When i did it, so much smoke and crap came out the exhaust i couldnt even see across the street! Which it should smoke a little bit, but not like a james bond smoke screen. I ran a whole bottle through this way( not at once, spread out over a month or 2) and it smoked much less after that and finally got to a normal level. Now this is where people like to argue with me and they say all of that smoke is bad for your cats and it will damage them or your o2 sensor. Iv done this on a bunch of cars and iv never seen this happen but that not saying it cant. I would think that the seafoam would clean the cat and not kill it, but thats just what people tell me.

I swear by it, others wouldnt dream of using it. So it remains up to you to make up your own mind. Anyway, that might be a little more info then you were looking for but thats my two cents.

[TBFK]

Thanks for all the information! It really helps me out a lot.

@TurnNburn: When you use it in your vacuum lines, where do you pour it in?

[TurnNburn]

typically what i do is cut a soda can in half, and fill it half way up with seafoam. So there is aproximately 3-4 ounces in it. I always go through the vacuum line that actuates the BPV on my car cause its easiest to get too, but thats in a turbo car. In your NA you can just as easily use the break booster line. Just take note that when you pull it off you should hold your finger over the hole because you essentially just added a huge vacuum leak and your car will not run very well. You can do this by yourself, i usually do, but it is easier with a friend. The car must be at operating temp before you do this and i would recomend doing it where no one can see you because potentially a lot of smoke will come out which might be kind of embarrassing when people think your car is burning down.lol. Thats how it was with mine, although iv done a few cars where only nothing came out, it all is going to depend on how dirty everything is.

With one hand holding the seafoam, and the other holding your break line, rev the car up to at least 2k rpm. When you are ready, remove your finger and carefully place the brake line into cup and let the vacuum suck it up. Try to spread it out over a period of about 5 seconds and not all at once, AS SOON AS YOUR DONE TURN THE CAR OFF.This way the vaporized seafoam is still inside the engine and is not already exhausted. Now let the car sit for 20 minutes.

There will be white smoke coming out of your tail pipe, maybe a lot of it, this is normal. Now is a good time to look around your engine bay and look for any smoke coming out, as this is leaking from your exhaust or leaking PCV lines. After waiting 20 minutes, start up your car. It may start up harder then usual but shouldnt last long. As the engine warms back up it will start smoking again. And it might do it for 15 minutes at idle. What i do is after starting it, i wait about 2 minutes and then go drive it. Do some WOT pulls and get everything nice and hot. This will get everything out faster. Once its stops smoking, its done.

Please post back here with your results.

[TBFK]

Ok, so I put a pint of Seafoam in my gas tank when I filled it with 16 gallons, and 71 miles into it, my car threw the code P0420. So with that being said, is that the Upstream o2 Sensor or Dowstream o2 Sensor. I'll buy another bottle tonight after work and try my vacuum line, but to be honest, i'm a little nervous about doin it. lol.

[TBFK]

Try to spread it out over a period of about 5 seconds and not all at once

When you say that, do you mean let it suck up the Seafoam for five seconds, then plug it, and wait, then repeat the proccess until all 4oz are gone? Also, what does WOT stand for?

[Rubasu]

wide open throttle

[TBFK]

wide open throttle

Oh ok. Thank You.

[TBFK]

So I found that the break booster vacuum line only goes to the back driver side cylinder only. But I did it anyways, and drove through the neighbor hood right it all got sucked up, and their was a hell of a lot of smoke. lol. Now i'm looking for a vacuum line that feeds all the cylinders, and i'll try it again. Does anyone happen to know where i can find one that feeds all the cylinders?

[Legacy777]

Use the PCV valve. It will feed the main plenum and all cylinders. To get the PCV to open and suck in the seafoam, I use a hose that fits on the PCV fill it with some seafoam and then put my finger over the open end of the hose. This will create a vacuum in the hose which will open the valve and cause the seafoam to get sucked into the engine.

[TBFK]

Use the PCV valve. It will feed the main plenum and all cylinders. To get the PCV to open and suck in the seafoam, I use a hose that fits on the PCV fill it with some seafoam and then put my finger over the open end of the hose. This will create a vacuum in the hose which will open the valve and cause the seafoam to get sucked into the engine.

Ok, so unhook it, fill it up while the car's off, and plug, start the car, and hold the RPMs at 2000?

[Legacy777]

You can remove the PCV hose while the engine is running, and then slowly add a little bit of seafoam to the hose. Yes, keep the rpm's up when you plug the open end of the hose.

[TBFK]

Ok, thank you Josh!

[TurnNburn]

Well im sorry to hear you ended up throwing a code. That code relates to the downstream o2 sensor, and in my experience usually points to the cat and maybe not the sensor the itself. Although, if it has been a long time since that sensor has been changed it could be that. Although im not really sure why a cel would pop up if all you did was put it in your gas. That is kind of wierd. Do you have a scanner? Is that how you know its that code? Did that code stay on?

[TBFK]

Well im sorry to hear you ended up throwing a code. That code relates to the downstream o2 sensor, and in my experience usually points to the cat and maybe not the sensor the itself. Although, if it has been a long time since that sensor has been changed it could be that. Although im not really sure why a cel would pop up if all you did was put it in your gas. That is kind of wierd. Do you have a scanner? Is that how you know its that code? Did that code stay on?

I do have a scanner. I don't know when the last time those o2 sensors have been replaced. I cleared the DTC and it hasn't came back yet. Hopefully it doesn't. Today after work though i'll be running the Seafoam into the engine through the PCV.

[evolutionmovement]

It was probably just from shit blown out with the help of the Seafoam causing a temporary problem with the O2. Coincidentally, the same thing happened with my Mazda last week due to a misfire because the original spark plugs had 135k miles on them. Replaced plugs, cleared code. Fixed.

[TBFK]

Well I used my scanner and my Catalyst Monitor, o2 Monitors, and EGR Monitors all say ok. So I think i'm in the clear now.

[TBFK]

You can remove the PCV hose while the engine is running, and then slowly add a little bit of seafoam to the hose. Yes, keep the rpm's up when you plug the open end of the hose.

I tried using the PCV Hose, but it didn't suck up the Seafoam?? So does that mean I need a new PCV Valve? Did it on a friends Honda today and their was an insane amount of smoke! A couple neighbors came over to see if everything was ok, haha.

[TurnNburn]

Iv never gone through the PCV valve so idk. But you can tell if its not working if you take it off and shake it. It should rattle around. I would recommend changing it anyway, its literally 3 bucks for a new one.

[Legacy777]

You can remove the PCV hose while the engine is running, and then slowly add a little bit of seafoam to the hose. Yes, keep the rpm's up when you plug the open end of the hose.

I tried using the PCV Hose, but it didn't suck up the Seafoam?? So does that mean I need a new PCV Valve? Did it on a friends Honda today and their was an insane amount of smoke! A couple neighbors came over to see if everything was ok, haha.

Did you put your finger over the end of the hose once you put the seafoam in it?

[TBFK]

You can remove the PCV hose while the engine is running, and then slowly add a little bit of seafoam to the hose. Yes, keep the rpm's up when you plug the open end of the hose.

I tried using the PCV Hose, but it didn't suck up the Seafoam?? So does that mean I need a new PCV Valve? Did it on a friends Honda today and their was an insane amount of smoke! A couple neighbors came over to see if everything was ok, haha.

Did you put your finger over the end of the hose once you put the seafoam in it?

Yeah, and also I noticed that i'm only getting about 11mpg or less. Let's just say I filled the tank with 16 gallons, and have gone less then 145 miles.

[Legacy777]

Yeah you may want to look at replacing your PCV valve.

As for your mileage....that's not too good. Have you done any routine maintenance recently?

[keithmoilanen]

Yeah you may want to look at replacing your PCV valve.

As for your mileage....that's not too good. Have you done any routine maintenance recently?

i am only getting 14 mpg in my 91 legacy turbo, what should i be getting?