Hey all,

After coming across Eurotrash Motorsports' video on B12 piston soaking the 2.0T, I decided to give it a try myself. Before going any further, I'd like to say thank you to Eurotrash Motorsports.

Video here

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Context:

My 2013 A4 2.0T has 156,000km (97k miles) and was burning (the weeks leading up to the soak) about 1L/280km, or about 1qt/170 miles. It wasn't always this bad, but deteriorated rapidly. The car already had timing and water pump done, brakes/rotors all around recently, and I love it, so I didn't want to just give up on it. I'm also not comfortable selling the car to someone in that condition. Anyway, by the time my trip had 100 km driven on it, I was down almost half a qt.

With this in mind, I had nothing to lose before just getting a new engine.

Theory

The logic behind this soak is that a component of the engine is dirty, and thus not functioning as intended; cleaning this component should improve its function. In this case, as we all know, it's the piston rings. Pouring seafoam or STP, which are lubricants, into the oil fill, driving around a bit, and hoping for improvement is one thing. Pulling the plugs and pouring solvent directly onto the pistons is another. I'm well aware that this is not a permanent fix; the rings will get clogged again, blowby will increase, and they'll have to be cleaned again. Compared to the cost of a ring job, I'd prefer to keep doing this soak as much as required.


Soak

I'm not going to get into the way the soak is done since it's outlined in the video linked above, but I changed a couple of things. I scoped my pistons and 2 and 3 looked brand new, plugs were nice too. 1 and 4 were soaked and caked in layers of carbon. Knowing this, I kept scoping the pistons over 24 hours and added more B12 to whichever piston needed it. Unlike the video, I also turned the crank about 25 total revs over the 24 hours, pretty much every time I went into the garage.

What happens after the soak is up to you. The Toyota community is divided; some say absolutely do not even start the engine with B12 in it, some say take it on the highway. I split the difference and idled it for about 15 minutes. After this, I drained, kept the old filter, and did about 4L of Rotella T6 and 0.6L of varsol; ran the car for about 15 seconds and drained it all. I let it drain for over an hour as I went out to go get some more oil, a filter, and new plugs. After getting the new oil in, I bombed it down the highway in 3rd/4th sitting anywhere from 3k-5k.

Now, a couple of things that Eurotrash Motorsports may not have mentioned: starting the car with the B12 is difficult. You're likely to crank for 30+ seconds before it runs. My battery started to die several second before it finally turned over and ran. In hindsight, should have had a charger. This one I'm less sure about: the angle of the cylinders towards the passenger side is small but not insignificant, and the B12 tends to pool that way when sitting on the piston. It may be worth jacking the car up a bit on the passenger side to level it.

Results

I've done 400km of driving since the soak, and my oil level has not gone down a single notch. Every time I check, I'm prepared for disappointment, yet it's still full. I don't know how long this'll last, but it feels amazing. There were night where I'd lay in bed thinking about the cash for a piston ring job, or the morality of selling the car as is.

What's evident is that the B12 did what a solvent does, and what Seafoam or STP can't do, and it dislodged the carbon sitting on the rings. How long before they're clogged again, I don't know.

Watch the video above and decide for yourselves!