Several people have asked how to do this so I've put together the following DIY, this will apply to all versions of the V6. Before I start let me just say there are several variations on how to use this product but I'm going to at least show you the best way to deliver Seafoam into the engine as well as my best opinion on how to much to use and where to use it.
First off your car needs to meet the following criteria:
- Must be within ~100 miles of your next oil change interval, you're going to put Seafoam in your oil which will thin it slightly, so also don't do this if you're overdue for an oil change
- The car must be cold, do not Seafoam a hot engine or you could risk it igniting inside your crankcase
What you will need:
- 1 16oz. bottle of Seafoam, can be purchased at any auto store
- 1 measuring cup that you won't ever use in the kitchen again (I happen to have one I use for car stuff, measuring catch can collection, etc)
- 1 length of 1/2" ID hose approximately 2 feet long, fuel line, trans cooler line, whatever you can easily source from your local parts store
- A pair of pliers or a socket to remove the PCV hose from the intake plenum, I have a catch can so mine is attached with a hose clamp that requires a socket, if your PCV hose is stock then you'll need pliers for the pinch clamp that's on there
- A funnel
- Someone to help you, as you're introducing the Seafoam to the car it will want to stall and because we have an electronic throttle you can't hold the throttle open slightly from the engine bay
- Optional: A code scanner in case you get a vacuum leak CEL that needs to be cleared
Step 1: Remove the PCV hose from the intake plenum, use your wrench or pliers to loosen the clamp and pull it down the hose an inch or so, then rocking and twisting ease the hose off of the nipple.
Step 2: Move the PCV hose aside, red circle again below, if you're not using the stock pinch clamp I'd remove your clamp like I did so it doesn't fall into the engine bay, the pinch clamp will stay on the hose. Now run your length of 1/2" hose under the intake and throttle body from the front of the car and up to the hose nipple, work the hose onto the nipple, the hose will fit snugly with some force but don't force it too much. You won't need a clamp to hold the hose on there.
Step 3: Measure out the Seafoam that will go into your intake, here's where techniques can differ. For the oil treatment the product recommends using 1.5oz per quart of oil, with our ~5.5qt capacity that's 8.25oz. of Seafoam, I'm rounding to 8.5oz., leaving 7.5oz. which I will put into the intake. One of the other uses of Seafoam is as a fuel treatment to help clean injectors but I use only premium detergent fuel so I'm going to skip that step and use the entire can in my intake and oil. Some people recommend a 1/3 technique, putting 1/3 of the can in the intake, 1/3 in the oil and 1/3 in the fuel, you can do that as well if you want to cover all of your bases.
Step 4: Have your helper get in the car and start it, it will run rough as you have created a vacuum leak by disconnecting the PCV hose, you will also likely get a vacuum leak CEL, nothing to worry about as you're only running it like this for a minute or two. Have them give the car gas as needed to help keep the car from stalling as you introduce the Seafoam, 1000-2000 RPMs or so. Take the end of the hose and while holding it against the inside of the measuring cup slowly lower it towards the Seafoam until the vacuum starts to suck up the liquid, don't stick the hose into the Seafoam, remember you want to introduce it slowly. Let the car suck up the liquid at it's own pace until you get to the last ounce or so, once you get to the last ounce plunge the hose in and let the car suck in the remaining fluid all at once and immediately after have your helper cut the engine, this last step will ensure a healthy dose of the Seafoam is in the crankcase to help break up deposits as it sits.
I don't have a picture of this part sorry, it takes two hands!
Step 5: Let the car sit for 30 minutes. While you do add the remaining Seafoam to your oil using your funnel and reattach the PCV hose to the intake plenum. If you got a CEL from the process you can clear it now with a scanner, the code should also clear itself after some normal driving.
Step 6: After 30 minutes start the car and let it run for a while, it'll run rough at first and you're going to get a lot of white smoke, keep the car idling until the smoke starts to decrease and the engine runs smoothly again. Now take it for a drive to help clear the remaining Seafoam from the intake and crankcase, about 10 miles, you'll continue to get some smoke for the first couple of miles.
You can plan to do your last ~100 miles of driving now and change your oil right away when you get back, or plan a time in the next couple of days to do the oil change, just don't let it go too long!
That's it! I plan on doing this every 10,000 miles or every other oil change since I have the GDI V6, hopefully along with my catch cans it will help ensure my engine will see as little valve deposit build up as possible.