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The Pork Wagon (‘14 Cop Charger)
7,747 Posts
Discussion Starter #1
This is related to what's known as a piston soak, but this is aimed at cleaning valves of any carbon deposits that might have built up over time/miles. As an added bonus, it will actually morph into a piston soak of sorts, but that's not the primary goal of this procedure.

First thing you'll need is some good deposit cleaner. I have chosen some Gumout Regane Direct Injection Cleaner (with PEA):

Regane Gumout with PEA.jpg

Make note of that "with PEA" part, as it's the best cleaner of carbon deposits you'll find for sale OTC. Any Gumout product that also has "Regane" in its name will have the PEA. Chevron's Techron is also a PEA cleaner, but it is not sold in aerosol form, so that particular product above is the best one I've seen for sale around here.

Next, you'll need to remove the engine's intake plenum and anything else that might prevent you from accessing the intake runners that are directly above the intake valves and combustion chamber. Then pull all the spark plugs (or at least one if you multiple per cylinder). This step could wait until you've finished the soaking part, but I would do it now since it will make manually rotating the engine easier in the coming steps.

Once you've got all that out of the way, check each intake runner to see the position of the valves - they will either be open or closed. If your intake is configured such that you cannot see the top of the valves through the intake runners, you may not want to attempt this procedure since you won't know how much cleaner is eventually getting into the combustion chambers.

For the cylinders with closed valves, spray a couple of bursts into the runner so that the cleaner will collect down on top of the valves and do its work. You'll be able to see it pooling on top of the valves, it will look something like this:

valves soaking 01.jpg

or this:

valves soaking 02.jpg

or even this:

valves soaking 03.jpg

Once you have done that to all of the cylinders with closed valves, let it sit and soak for a while. How long is up to you, but the longer the better obviously. Overnight is probably ideal.

Anyway, once you're read to move to the next step then manually rotate the engine a couple of revolutions until the cylinders that had open valves now have closed ones. For the cylinders that had closed valves and pooled cleaner, they should now look like this:

open valves.jpg

(Keep in mind all of that liquid cleaner is now sitting in the combustion chamber doing its thing to the top of the piston!)

Let these valves soak as long as possible like before, and then manually rotate the engine again. Now you are pretty much done unless you want to let the cleaner soak on top of the pistons some more. But once you are ready to button everything back up, you will need to clean that cleaner out of the combustion chambers first. If you were to just put the plugs back in and try to start it, you risk something call hydro-lock, which is very bad and best avoided.

To prevent hydro-lock, you cannot have any liquid in the combustion chambers when the piston is on the compression stroke (liquids don't compress!), so this is where the spark plugs being removed really comes in handy. Before continuing here, you'll want to pull the fuses for the fuel pump and fuel injector coils though, which should be both the front and rear fuse boxes (one each). On my Challenger, the front fuse box had the fuel injector coil fuse, and the rear fuse box had the fuel pump fuse. Yours may be different, but if you have the owner's manual handy, it should be easy to ascertain which fuses are which.

Once you have the fuses pulled, then cover the intake runners with something to keep any errant bugs or small kittens from being ingested while the engine is rotating in the next step. I used some cardboard laid down over the intake ports and under the fuel rails. You don't need to get fancy, just cover them to be safe.

Once you're ready to go, get in the car and start it. Now obviously it will not actually start, but the engine will turn over as though it was, and in doing so, it will expel the cleaner liquid out of the spark plug holes and just generally evacuate the combustion chambers. After it's turned over for 5-8 seconds, that should be fine. You can kill the starter and check the combustion chambers by shining a flashlight through the spark plug holes. If you don't see any liquid, you're good to go. Reinstall the plugs and plenum, and you're ready to go!

If you still see some liquid, bump the starter again and let it turn over for another 5-10 seconds. That should be plenty. Verify there is no liquid in the combustion chambers and then button everything up and go on about your rat killing.

One last thing - it wouldn't hurt to perform an oil change pretty quickly after this procedure just in case any of the liquid cleaner slipped past the rings while the engine was being turned over. That would have made it into the engine oil, thereby diluting it, and the only way to get rid of that would be to do an oil change and get some fresh oil in there.

That's it, good luck, and god speed!!

Nuke, OUT!!
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