Seafoam on 2003 Sentra SE-R

[jhuman]

I would like to perform a seafoam engine clean on my 2003 SE-R with 141K miles and I have some questions and would really appreciate your help or guidance toward the answers:
1) First is it safe/ worth it to do it on a vehicle with this mileage that has never had it done before?
2) I've researched throughout the forums and checked the FSM but still don't know where is the check valve is on the brake booster line and where I should disconnect the hose to add in the seafoam. Could someone post a pic pointing this out?
3) If I wanted to hook up a smaller hose to the brake booster line to have the hose "sip" seafoam from the can instead of pouring down the booster line, what size hose should i buy?
4) I've read in the guide by AZhitman that says you should change out your spark plugs after you seafoam. I put new spark plugs in a week ago and was wondering if I should put my old ones back in, seafoam, then after put the new sparks back in?

Thanks for help in advance and appreciate any other advice you can give me regarding this project.

[AZhitman]

Hey J - I'll try to help here if I can...

1) "Safe" and "worth it" are relative terms. It's hard to know the condition of your engine, so that's impossible to answer. However, your engine is no different than the thousands and thousands of others that need a good cleaning.

2) Here's where you disconnect:


3) 5/16" is the inside diameter of your booster line, but I'm going to suggest you do some measuring on your own for that part.

4) Wouldn't hurt, but I'm not a fan of messing with the plugs over and over - too many chances to cross-thread or damage a plug or the head. It'll be fine with the new plugs.

Good luck and have fun!

[jhuman]

Hi AZ, thanks for your advice. I tried doing it myself today. I know you recommend having an assistant but it was a little late and couldn't get my buddy to come help me so I jerry-rigged a weight on the gas pedal that was able to keep the RPM at 2000. Then I go and disconnect the brake booster line exactly where you pictured and the engine immediately cut out. Tried it again and same thing. I was reading on some other forums and they say that cars with a MAF sensor have a hard time keeping idle after the brake booster is disconnected and they suggest disconnecting the MAF itself and then going through with the seafoam process. Have you ever experienced anything like this?

[AZhitman]

Hmmm. Not really. You can disconnect the MAF plug and try it again.

If that doesn't work, let's look on the manifold and select a different (smaller) vacuum location. Without a good pic of the manifold, I'm at a loss for which fitting to use, but it shouldn't be hard to select one.

[jhuman]

should I disconnect the MAF before I start the car?

[jhuman]

Here are some pics of my manifold, let me know if you need better ones or something from a different angle

[AZhitman]

I'd work with the one off the back of the manifold (with the silver pinch clamp) - 3rd pic.

You can d/c the maf plug before starting, or after - no matter.

[jhuman]

are you talking about this hose circled? If so, that is the brake booster line that I've been using

[AZhitman]

Yep. Or. look around the manifold and find one that "sucks" with the engine running.

Realistically, the engine should NOT die with that disconnected, though. Try unplugging the MAF.

[jhuman]

So yesterday I unplugged the MAF and disconnected the brake booster and it stalled out again. So then I tried very gradually removing the brake booster line, meanwhile trying to keep my finger over the hose. I eventually managed to get it off but had to wait at a few intervals as I was sliding off the brake booster line to let the engine catch itself from stalling. I think that's the way to go instead of just pulling it off in one go as I had been doing.

[AZhitman]

Good call. Having someone modulate the throttle will help as well.

[jhuman]

I finally got around to performing the seafoam on my car. Having a buddy keep the RPMs up is definitely the way to go. I followed AZhitman's guide, found here http://tiny.cc/wl5sgx, and everything went pretty well and was completely straight forward. Although there was smoke, there wasn't as much as I thought there would be and it was all gone within 5 minutes of my turning on the car and going off for a "spirited" drive. My initial thoughts on the effects of the seafoam are that my car idles quieter and generally shifts a bit smoother. These are the only differences I've noticed so far. AZ, thank you for all your help.

[AZhitman]

You bet!

Make sure you do an oil change in the next several days, and maybe run an extra-heavy dose of fuel injector cleaner through the tank.