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that is really not bad considering the turbo GDI territory 73kMi 👍
Lower mileage engines have been shown with much thicker buildup on the intake valve stems.
The valves buildup is 100% from non combusted vaporized oil.
What is the look of cylinder walls above pistons side where deposits can buildup?
Inside combustion chambers oil carbon is combusted... only SP/SN package heavies are left behind.
are all of our cars in this state of condition? If not yet have cleaned up?
I can't tell a difference yet in 2 hours of highway driving but My MPG meter MAY be showing an improvement. I'll watch it for at least 3 tanks before I'll be convinced.
The only real fix is port injection AND direct injection which Lexus figured out from Day 1 with the LS460 in 2007. All of the Germans took the lazy way out with DI only.
Probably. Some may be worse depending on how much oil is consumed. Mine has never even consumed more than a quart every 5k miles.
1 quart every 1250 miles out of its life with me, it is floored every time its driven, average map about 12.5. and like mentioned, clean bores but two dirty rings which ive been working on. In my pics im guessing they would be dirtier without my having hit them with chems as you can see in my first pics the left valve was slightly cleaned before the mechanic cleaned them. Im happy to be corrected but when I injected the Berryman gdi chems in the port directly in the rear top of the intake (center pcv hose port) its a slow metered mist that goes down into the valves through the intake almost unobstructed. At least thats what pictures and diagrams indicated to me. The amount of smoke in my neighborhood was insane and ive done clean engines like a Lexus that have zero smoke. I have seen people try to recommend injecting pre intercooler which makes zero sense. When looking at the pic of the plastic intake, yes While id never say the chems can clean a car with miles, I would say it will keep them cleaner from after cleaning...
Any reason why injecting in the port in ONE below would have NO effect or negative effect not to include hydrolocking or other fears.. While its not perfect, it been fine for me and the most direct route to the valves.
The reason injecting in one of the open vacuum ports would not suffice is because it’s to stubborn after all these years going through thousands of heat cycles. I have to literally scrape carbon deposits off, I can assure you the normal process will not work the way we need it to work unfortunately. Secondly it’s just not enough chemicals hitting the valve to start breaking it down because it’s a v8 and has to be divided amongst all 8 cylinders.. I’ve tried it just to try. In fact I drilled a hole on the intake by cylinder 5 in an engine I was taking apart . So I used this for some testing for my own personal tests. This is years ago, I’ve been pointing this problem out for many years so I have a head start on testing multiple m157’s . The only way to properly clean these valves is to remove the intake. But we can’t forget to do the sticky rings, and TDC carbon buildup,
. This area will cause scoring if build up is adequate. Just slide a bore scope in and see how it looks, if you see it’s starting to pull carbon down then it’s time, if it’s not bad then just the valves are fine. Also these piston and injectors work together, the dish on the piston is what helps distribute the fuel outwards uniformly helping atomize the fuel for an efficient burn. The carbon buildup up on the piston limit this efficiency. So there is benefits to cleaning the piston tops as well. Sometimes you can see the injection spray pattern on top of the piston in the center of the dish
I was thinking some sort of treatment.
Everything I've read about catch cans doesn't convince Me on those.
how about a sort of PTFE "Teflon" non-stick valve coating?
The trouble is oils are formulated to stick very well with polar molecules that cling on anything, especially each other... build-ups. my valves as-is @72K... Note valve temp pattern
It's interesting to witness deposit is directly tied to valve heat, deposit is not where oil contact valves.
Overall there is not one single perfect solution. Only a combination of details can make a difference to control deposits.
The key to oil deposit control is tied to HEAT control.
Less vaporized oil, builds-up less onto valves with less heat.
Some oil formulations carry low levels of additives to burn cleaner vs. more build up.
Last edited by CaliBenzDriver; Jan 25, 2026 at 04:04 PM.
So is there a way to periodically reduce the rate of build up on valves?
5w50 oil, it’s a better viscosity. It’s what I found helps a good bit. Make sure the pcv system is operating properly, or change it out. This is the nature of direct injection unfortunately. It’s designed to dump crank case ventilation through the turbos and out the engine, there’s no way around it. But ways to limit until the point where you can have it cleaned. What this looks like for most is probably one time since not many will keep this car for more then 100k miles, what this looks like for the person who will keep this car long term or even considering rebuilding when it’s due . I would say every 40k , just have the valves done or both valves and cylinders cleaned. Which is 3 plus years if you use the 15k per year a mile avg that most do.
The reason injecting in one of the open vacuum ports would not suffice is because it’s to stubborn after all these years going through thousands of heat cycles. I have to literally scrape carbon deposits off, I can assure you the normal process will not work the way we need it to work unfortunately. Secondly it’s just not enough chemicals hitting the valve to start breaking it down because it’s a v8 and has to be divided amongst all 8 cylinders.. I’ve tried it just to try. In fact I drilled a hole on the intake by cylinder 5 in an engine I was taking apart . So I used this for some testing for my own personal tests. This is years ago, I’ve been pointing this problem out for many years so I have a head start on testing multiple m157’s . The only way to properly clean these valves is to remove the intake. But we can’t forget to do the sticky rings, and TDC carbon buildup,
. This area will cause scoring if build up is adequate. Just slide a bore scope in and see how it looks, if you see it’s starting to pull carbon down then it’s time, if it’s not bad then just the valves are fine. Also these piston and injectors work together, the dish on the piston is what helps distribute the fuel outwards uniformly helping atomize the fuel for an efficient burn. The carbon buildup up on the piston limit this efficiency. So there is benefits to cleaning the piston tops as well. Sometimes you can see the injection spray pattern on top of the piston in the center of the dish
I agree that it can not Clean old sludge well. But do you think it has benefits when used as maintenance of clean valves (after walnuts etc). My thought is that that small amount of chem is better than nothing especially if done at every oil change or two.
5w50 oil, it’s a better viscosity. It’s what I found helps a good bit. Make sure the pcv system is operating properly, or change it out. This is the nature of direct injection unfortunately. It’s designed to dump crank case ventilation through the turbos and out the engine, there’s no way around it. But ways to limit until the point where you can have it cleaned. What this looks like for most is probably one time since not many will keep this car for more then 100k miles, what this looks like for the person who will keep this car long term or even considering rebuilding when it’s due . I would say every 40k , just have the valves done or both valves and cylinders cleaned. Which is 3 plus years if you use the 15k per year a mile avg that most do.
I've been using the Motul 5W-50 for awhile. I'll just plan on walnuts in another 40k.
I agree that it can not Clean old sludge well. But do you think it has benefits when used as maintenance of clean valves (after walnuts etc). My thought is that that small amount of chem is better than nothing especially if done at every oil change or two.
mmm this may work. Seems plausible. Perhaps this can clean off what’s loose and over time keep an eye on them to see which is building up and which is actually being cleaned a bit from the chems
mmm this may work. Seems plausible. Perhaps this can clean off what’s loose and over time keep an eye on them to see which is building up and which is actually being cleaned a bit from the chems
This is my plan, though I put very few miles on per year. 5/50sp, pea in gas per instructions, occasional intake clean (IMO berryman's has the best metering but is not the highest pea), and im back and forth on the solenoid. Lots of commuting this year so mileage may change when I get sick of the other vehicle.
This is my plan, though I put very few miles on per year. 5/50sp, pea in gas per instructions, occasional intake clean (IMO berryman's has the best metering but is not the highest pea), and im back and forth on the solenoid. Lots of commuting this year so mileage may change when I get sick of the other vehicle.
That's pretty much My plan too now that I know the valves are clean. Just gotta figure which treatment to use. Youtube is full of experiments, not sure I trust a lot of them.
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