# Carbon build up on Valves? Prevention? Treatment? How often to change oil? **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** integra, acura\ **Created:** [March 22, 2021, 8:04pm UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779 "2021-03-22T20:04:19Z")\ **Posts on this page:** 20\ **Page:** 5
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [April 7, 2021, 3:01am UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/82 "2021-04-07T03:01:18Z")
> [@circuitsmith](#): > > Watch for change in fuel trims. I tried it when the car is hot and its on Closed Loop. No improvement on fuel trims - I am uncertain as to how much I pinched, so I repeated it - still no improvement on FT. I might have to build a smoke machine or find another mechanic. Am I correct that I should be doing these tests on Closed Loop? I also have a flowchart from the car manual - so wondering CL or not? ---
**Author:** ![VOLVO-V70](https://avatars.discourse-cdn.com/v4/letter/v/8e8cbc/32.png) [@VOLVO-V70](https://community.cartalk.com/u/VOLVO-V70)\ **Post date:** [April 7, 2021, 12:33pm UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/83 "2021-04-07T12:33:54Z")
> [@sciconf](#): > > find another mechanic. Bingo , finally we have a winning idea šŸ˜² ---
**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\ **Post date:** [April 7, 2021, 2:52pm UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/84 "2021-04-07T14:52:00Z")
> [@sciconf](#): > > so wondering CL or not? Yes, closed loop. ---
**Author:** ![thegreendrag0n](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/thegreendrag0n/32/9265_2.png) [@thegreendrag0n](https://community.cartalk.com/u/thegreendrag0n)\ **Post date:** [April 7, 2021, 5:48pm UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/85 "2021-04-07T17:48:26Z")
> [@sciconf](#): > > so wondering CL or not? ohā€¦ my first impression reading this quote was if @sciconf is about to CraigList this beast šŸ™‚ my mistake! ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [April 7, 2021, 6:38pm UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/86 "2021-04-07T18:38:48Z")
> [@thegreendrag0n](#): > > > [@sciconf](#): > > > > so wondering CL or not? > > ohā€¦ my first impression reading this quote was if @sciconf is about to CraigList this beast šŸ™‚ > > my mistake! Looks like I am getting ready for a ASE certification! I had to tell this expert m/c to focus on injectors which he ruled out earlier based on his ohm test. Where can I buy Cigars for my Smoke machine? ---
**Author:** ![thegreendrag0n](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/thegreendrag0n/32/9265_2.png) [@thegreendrag0n](https://community.cartalk.com/u/thegreendrag0n)\ **Post date:** [April 7, 2021, 6:45pm UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/87 "2021-04-07T18:45:05Z")
> [@sciconf](#): > > I had to tell this expert m/c to focus on injectors which he ruled out earlier Donā€™t go overboard on that or (as me) you can get labeled a troublemaker and banned from the shop šŸ™‚ Still, I felt no guilt to point to blatant lie where the shop started to throw parts on the problem and when I asked if they made a smoke machine test, they said ā€œyes, and everything was sound!ā€ and yet I caught them on exhaust system having a hole big enough to fit a quarter ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [April 7, 2021, 6:50pm UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/88 "2021-04-07T18:50:21Z")
> [@thegreendrag0n](#): > > Donā€™t go overboard on that or (as me) you can get labeled a troublemaker and banned from the shop True, I told him a story as if someone was guiding me. It worked. I still have respect for him - he is very good and go slow and steady on the car. Next visit, he demoed me that the misfire followed with injector justifying the need for the new injectors. ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [April 7, 2021, 6:52pm UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/89 "2021-04-07T18:52:31Z")
Where can I buy a Cigar for my Smoke machine? ---
**Author:** ![thegreendrag0n](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/thegreendrag0n/32/9265_2.png) [@thegreendrag0n](https://community.cartalk.com/u/thegreendrag0n)\ **Post date:** [April 7, 2021, 6:54pm UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/90 "2021-04-07T18:54:24Z")
here is some idea for you: [![](https://global.discourse-cdn.com/cartalk/original/3X/2/d/2d2a9a6086053eeb92022e7e586906ef2a6c5878.jpeg "DIY Smoke Machine For Vacuum or EVAP Leaks E46 P0171 P0174") ](https://www.youtube.com/watch?v=Np_duzsaZxI) you do not need to go overboard with a pressure regulator, just be careful how much pressure you create from your pressurized air source ahā€¦ and the canā€™s lid works as a safety valveā€¦ just from experience šŸ™‚ ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [April 7, 2021, 7:21pm UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/91 "2021-04-07T19:21:33Z")
I am thinking of this one - what do u think? [https://youtu.be/GOhl4r0GSiE](https://youtu.be/GOhl4r0GSiE) ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [April 7, 2021, 7:32pm UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/92 "2021-04-07T19:32:07Z")
Remove MAP sensor while smoking? This means, another test is needed to ensure its not leaking where MAP is attached! ---
**Author:** ![thegreendrag0n](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/thegreendrag0n/32/9265_2.png) [@thegreendrag0n](https://community.cartalk.com/u/thegreendrag0n)\ **Post date:** [April 7, 2021, 7:35pm UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/93 "2021-04-07T19:35:12Z")
from the amount of smoke it would produceā€¦ I would think itā€™s a jokeā€¦ if you had a hole the size of your fingerā€¦ maybe you would see that, but I would not expect to find any smaller ones ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [April 13, 2021, 6:13am UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/94 "2021-04-13T06:13:26Z")
P0171 issue ā€“ I had a used, but newer, MAP sensor ā€“ so I swapped it ā€“ seems a little better. ā€“ The photo below is soon after changing the MAP ā€“ car was resting for just 1 hr. You can see the STFT slowly ramping (green) on closed loop. The red is the front O2 sensor. Gear is on Park. ![Screenshot_20210412-185600_ThinkCar](https://global.discourse-cdn.com/cartalk/original/3X/2/8/289563833b1d0493b54a1e4a7f8482e666c9781e.jpeg) ā€“ This issue started soon after vacuum leak on IACV was fixed with a new gasket. Wondering if I should loosen the IACV bolts and see if the issue goes away? ā€“ I took it for a short ride and then put it on Park. When the car is idling (Closed loop) on Drive gear, MAP is giving higher reading of 5.36psi. If I shifted to Park, MAP gives lower value, 4.2psi and STFT increases, hence LTFT increases. I was moving Park to Drive (and back and forth - each time MAP value is affected). You can see it in the photo below. ![Screenshot_20210412-190831_ThinkCar](https://global.discourse-cdn.com/cartalk/original/3X/2/5/25b5646102f74989d70c857d46e2e57ee29fa042.jpeg) ā€“ Does this have anything to do with Idle Air Control Valve? Faulty or Malfunctioning? I call around shops and couple of them never answered my question as to if they have Smoke m/c. So its taking time to find good m/c with a Smoke m/c. ---
**Author:** ![MikeInNH](https://avatars.discourse-cdn.com/v4/letter/m/a587f6/32.png) [@MikeInNH](https://community.cartalk.com/u/MikeInNH)\ **Post date:** [April 13, 2021, 1:18pm UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/95 "2021-04-13T13:18:22Z")
> [@shadowfax](#): > > If you have a direct injection engine, just resign yourself to getting/performing an induction cleaning every once in awhile. Unlike older designs, fuel no longer washes over the valves in DI engines, which means whatever lands on the valve stays there instead of being flushed away. Not ALL direct injection systems. Toyota has D4S system that is both Direct Injection and Port Injection that helps prevent carbon buildup on the valves. [Toyota Advances D4S With Self-Cleaning Feature on Tacoma (wardsauto.com)](https://www.wardsauto.com/technology/toyota-advances-d4s-self-cleaning-feature-tacoma) ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [April 18, 2021, 2:17am UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/96 "2021-04-18T02:17:42Z")
> [@shanonia](#): > > I used Marvel Mystery Oil in my gasoline after my 1984 Chevy 2.0 engine started some preignition knock when accelerating. I thought carbon buildup may have been the cause. The problem went away and I kept using the MMO. Somewhere under 200,000 miles I had the head off and the machine shop guy remarked on how clean the innards were compared to many he saw. Once the Fuel trim issue is addressed, I will start using MMO. Thanks ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [April 18, 2021, 2:28am UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/97 "2021-04-18T02:28:42Z")
> [@thegreendrag0n](#): > > Donā€™t go overboard on that or (as me) you can get labeled a troublemaker and banned from the shop šŸ™‚ > > Still, I felt no guilt to point to blatant lie where the shop started to throw parts on the problem and when I asked if they made a smoke machine test, they said ā€œyes, and everything was sound!ā€ and yet I caught them on exhaust system having a hole big enough to fit a quarter Although my car passed SMOG now, the Fuel trim maxing out on idle is still there but lesser than before. I will be taking it to a shop shortly when I get time. There might be a leak on the EVAP - EVAP monitor is still not ready! Thanks everyone for the help. ---
**Author:** ![oilman](https://avatars.discourse-cdn.com/v4/letter/o/91b2a8/32.png) [@oilman](https://community.cartalk.com/u/oilman)\ **Post date:** [April 21, 2021, 5:52pm UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/98 "2021-04-21T17:52:59Z")
put two changes of Royal Purple in the engine back to back and that should make things a lot cleaner. Royal purple has a lot of information on the net about cleaning the inside of the engine. Sorry, but itā€™s there. I love oil!!! ---
**Author:** ![sciconf](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sciconf](https://community.cartalk.com/u/sciconf)\ **Post date:** [April 21, 2021, 6:10pm UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/99 "2021-04-21T18:10:42Z")
> [@oilman](#): > > put two changes of Royal Purple in the engine back to back and that should make things a lot cleaner. Royal purple has a lot of information on the net about cleaning the inside of the engine. Sorry, but itā€™s there. I love oil!!! Thank you @oilman - I will research move forward. Update: Could u share any tips and tricks? How often you would change, recommended oil filters? ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [April 21, 2021, 6:19pm UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/100 "2021-04-21T18:19:30Z")
Oil will have no effect on carbon buildup, nor will it clean it out. ---
**Author:** ![thegreendrag0n](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/thegreendrag0n/32/9265_2.png) [@thegreendrag0n](https://community.cartalk.com/u/thegreendrag0n)\ **Post date:** [April 21, 2021, 6:40pm UTC](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779/101 "2021-04-21T18:40:43Z")
> [@texases](#): > > Oil will have no effect on carbon buildup, nor will it clean it out. if you added ā€œsubstantialā€ to this statement, I would be 100% with you, so let me cover 1% where I do not agree it is a test, which a number of oil manufacturers tend to hide on their published specs: > **[Noack volatility test](https://en.wikipedia.org/wiki/Noack_volatility_test)** > > The Noack volatility test, named after Kurt Noack, determines the evaporation loss of lubricants in high-temperature service. This test is standardized as ASTM D5800. > In this test, a sample is heated at 250 Ā°C for 60 minutes with a constant flow of air over it. The weight fraction lost is the result for the Noack volatility test. > As the lighter hydrocarbon fraction of motor oils evaporate, the viscosity of the remaining oil increases, contributing to poor circulation, reduced fuel economy, inc... knowing this number, one can compare the expected difference in oil evaporation under high-temp conditions, so if one had two oils A and B on hands with all specs in complete match, but with Noack of A was higher than B, it is reasonable to expect that oil A will ā€œburnā€ faster in the engine having multiple Subarus in the past, which all used some oil between changes, selecting oil with lower Noack on the spec, it made a difference of having 0.5 quart down or 1-2 quarts down (and need to add) on 5000 miles interval I can totally imagine that the oil evaporating is not getting teleported to the alien world, but ends up partially in the combustion chamber and partially in internals, where it get picked up by crankshaft ventilation systemā€¦ eventually setting on the valvesā€¦ bingo! so, to some extent oil specs have a difference on carbon buildupā€¦ although itā€™s relatively minor factor to compare to the worn piston rings and old stuck PCV valves [Previous page](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779.md?page=4) [Next page](https://community.cartalk.com/t/carbon-build-up-on-valves-prevention-treatment-how-often-to-change-oil/175779.md?page=6)