Is Sea Foam® safe to use through a vacuum line?
Using Sea Foam® through a vacuum line is easy and safe if you remember one thing. Liquids don’t compress and can cause an engine to hydro lock if too much liquid is applied. Always regulate the rate at which Sea Foam® goes into the engine. Never insert the vacuum line into the bottle of Sea Foam®, always pour Sea Foam® slowly into the vacuum line. It is important to make sure the engine is at operating temperature. Then find a vacuum line that feeds all cylinders, usually the PCV hose or the vacuum brake booster line may feed all cylinders. If you are in doubt as to which vacuum line to use, YOU MUST check with a certified auto technician. If a technician is not available or if your engine doesn’t have any vacuum lines, then use the Sea Foam® Spray method described in another section of this web site. After the correct vacuum line has been located, start engine and disconnect vacuum line. With engine running at idle and at operating temperature slowly pour Sea Foam® into vacuum line. I
