I've heard it discussed here several times, and despite being a car guy for 45 years, have never heard of it.

Bob, Seafoam is a company name. They make several additives. Gasoline, trans, oil, etc.

Most references here are for top-end cleaning. Disconnect the large vacuum line on the top of the motor, and let it suck the stuff into your intake while idling. Smokes like an SOB, but it cleans the intake manifold, valves, and cylinders very well.

There'* several posts and topics regarding this.

http://www.seafoamsales.com/motorTuneUpTechGas.htm

You can pick it up at virtually any auto parts store except pep boys. Make sure you follow directions on the can and when you do the vacuum line method don't stick the hose into the can to suck it up or you risk hydrolocking your engine. Rather pour it very slowly into the vacuum line (engine must be running, if it stalls, restart it). It takes me about 3 minutes to pour in half can. Shut the engine off, reconnect the line to the brake booster, and restart engine after 5 mins. It works great, but if you use some in the crankcase, do it about 500 miles before your oil change. I've done this many times on my grandfather'* bonneville, my dad'* nissan, and my toyota, so if you have any questions send me a message.

You can't hydrolock your engine that way. If it stalls, re-start it. You can only hydrolock by trying to start your car with cylinders already filled with liquid. When the engine stalls from over-feeding seafoam, vacuum goes away and it doesn't suck any more anyway.

Your engine hydrolocks when it ingests more liquid than it can compress thereby damaging the engine. Since no liquid is comperssable, too much seafoam in the cylinder at one time will damage your engine because your engine will try to compress it before it finally stalls out. The same thing happens if you ingest water from driving through a flooded area or offroading and stuff. My engine stalled a few times when doing seafoam before but it was not because of over seafoaming. It was due to the ecu not know what was going on when I pulled the vacuum line off the break booster. (I actually had to keep my thumb over the hose half-way covering the hole to keep it from stalling so at least some vacuum was generated). I researched a lot abut seafoam before actually running it though the inducation system in my truck for the first time, and I landed on an F150 forum and there were lots of guys there that stuck the hose into the can and ended up replacing their engines because of broken internals. You really do have to be careful when doing this and do it very slowly.

Your problem is you are using the Brake Booster line. That line has WAAAAY too much vaccum. That very well could cause a hydro-lock. Use a smaller line.. like the one for the vacuum modulator [if equipped], or just something.. a small line. You won't have any problems then. No way a small line could suck up enough liquid to hydrolock your engine.


-justin

Agreed, the break booster line makes a crapload of vacuum. I heard about this idea: use a needle that you use to pump up balls and attach it to the line. Then the vacuum is greatly reduced and it should work fine to just stick it in the can. I think the vacuum modulator is in the automatic transmission, and my truck is a stick, so that leaves me with the break booster and pcv line. But it works well for me to just very slowly pour (almost trickle) the seafoam into the break booster line and let the vacuum pull it in. It takes about 5 mins to do 1/3 can, but I think it eliminates the risk of hydrolocking. And the vacuum pulls it in so none of it is spilled.

It can't possibly ingest enough Seafoam to hydrolock, because the car will stall from incorrect AFR first. Hydrolock comes from improper safeties on a water injection system or having your car immersed in water like Drifter'*.

There isn't enough Seafoam in a bottle you buy off the shelf to even come close to hydrolocking.

i concurr with Will on this one

Drifter'*.. are you talking about drifer420, Murdock? Or drifters like those foreign cars slidding around like winter drivers?


-justin