I bought a Subaru Forester new in 2022, and I wanted to see if running IVC at regular intervals from the beginning would prevent or slow carbon build up. I couldn't see anywhere on YouTube or anything like that where it had been done in that capacity. It doesn't look like IVC does much once the carbon is already baked on after 50k or 70k miles, but does it help prevent it before that point?
The Forester has just under 20k miles. It's had 5 oil changes, between 4-5k mile intervals. I did the first one early, no IVC run through at that one, so I've used it 4 times.
My driving habits...21 mile mostly interstate commute, so the oil gets up to temp for 12-15 minutes each way depending on season. Some stop and go driving outside of that, of course.
I used STP Pro IVC for this. I chose this largely for it's simplicity of use as it can be done by one person, but it's definitely the expensive choice.
I'm sorry the pictures aren't great but here are the results. The stems look good, but there is some minor coking on the backs of the valves (I would say my poor pic quality makes it look a little worse than seeing it in person).
The mechanic doing this was interested to see the results as well as they also do the walnut shell treatments. The conclusion is that it probably has helped *some*, but I was hoping it would look a little better. I think it's about what I expected, though.
Of course, I don't have a baseline for comparison...another 20k mile 2.5L NA Subaru boxer engine with similar driving habits. Maybe it worked better than it appears? Maybe not. I couldn't find anything. I can't even find enough info to know if Subaru engines are known to carbon up quickly, or are they slower to do so...
Will I keep doing this? Not sure yet.
Any feedback is welcomed.
The Forester has just under 20k miles. It's had 5 oil changes, between 4-5k mile intervals. I did the first one early, no IVC run through at that one, so I've used it 4 times.
My driving habits...21 mile mostly interstate commute, so the oil gets up to temp for 12-15 minutes each way depending on season. Some stop and go driving outside of that, of course.
I used STP Pro IVC for this. I chose this largely for it's simplicity of use as it can be done by one person, but it's definitely the expensive choice.
I'm sorry the pictures aren't great but here are the results. The stems look good, but there is some minor coking on the backs of the valves (I would say my poor pic quality makes it look a little worse than seeing it in person).
The mechanic doing this was interested to see the results as well as they also do the walnut shell treatments. The conclusion is that it probably has helped *some*, but I was hoping it would look a little better. I think it's about what I expected, though.
Of course, I don't have a baseline for comparison...another 20k mile 2.5L NA Subaru boxer engine with similar driving habits. Maybe it worked better than it appears? Maybe not. I couldn't find anything. I can't even find enough info to know if Subaru engines are known to carbon up quickly, or are they slower to do so...
Will I keep doing this? Not sure yet.
Any feedback is welcomed.
