Most resilient oil to GDI intake desposits please

AMSOIL and Redline are the only ones that I'm aware of publishing their NOACK numbers. I think even Valvoline has mostly withdrawn them from their PDS. I think there are some Castrol PDS that have NOACK but those might be old formulations and not what is on shelves.

On the recent study that I saw, it's confusingly not straight forward what kind of oil can leave deposits. My only takeaway from that study was to change your top tier oil very frequently. Valve intake deposits seem to contain oil additives so it's not purely from combustion blowby. It seems oil vapor is depositing onto the intake valves themselves exacerbating the problem.

So if you want to try to minimize deposits between cleanings to maintain efficiency, reliability, and performance... the only clear thing to do in my view, is to frequently change as low NOACK oil you can find for your uses. For me, I'm planning to keep using Castrol 0w40 (which might not be good for turbo GDI due to 2k+ Ca) at 5k intervals. Redline 5w40 is 3% lower in NOACK but it's my theory that it's better to run Castrol 0w40 at 5k than Redline 5w40 at 10k in regards to valve deposits.
 
Originally Posted By: webfors
Originally Posted By: JustinH
What is an example of low noack oil?

I have been using synpower 5w30 in my GDI sonata for the past few years at 3750 intervals.

At 50k the car pinged so badly, I had to run a GDI cleaner through the engine while it was running.

It cleared up most of the pinging issue but about 10k miles later it still pings when the car is cold under load on 87 octane.

I also run techron at every oil change.


Here is a perfect sample of “evidence” for those that claim there is none. A quick search online will come with many examples of GDI engines that experience symptoms of carbon buildup. This example is most likely a result of cylinder buildup decreasing volume which increases compression, for which a higher octane gas is now needed.
Oh I'm not doubting that carbon buildup happens, I'm doubting whether it matters as far as longevity.
 
Originally Posted By: Speak2Mountain
Still, your car needs to be driven long and sometimes hard. Short tripping, esp in cold is rough on DI engines.

Don't baby your engine


Oh, it won't get babied! The feeling of full boost is intoxicating and addictive
grin.gif


The car handles like it's on rails, so hard cornering, exiting under full boost, rinse and repeat until tired.
 
Originally Posted By: Vuflanovsky
Originally Posted By: webfors
Originally Posted By: Vuflanovsky


The OP is looking for a blanket answer to a non-blanket answerable scenario.


Wrong. I’m asking for the experience of others with respect to what type of oil would be recommended in this application.

I’m not asking how to solve all of the problems inherent to GDI engines with a magic elixir.

This is an oil forum right?


Webfors said: "What oil brand, viscosity, and spec is the most resilient to contributing to intake carbon deposits on GDI engines?"

What I suggested as an unanswerable question is related to your specificity of oil brand, viscosity, and spec as it relates to carbon deposits. There's not one answer because GDI is not a monolithic block of technology with one design that's applied to the same engine.

I have a five year old naturally aspirated DI car where I use only synthetic oil, am cognizant of low volatility, and some other items that are more specific to my vehicle. Quality of the fuel may mean more to one vehicle than another with regards to carbon deposits. Same with weight or a singular spec. I seem to have no "inherent problems" in my DI car whereas turbo DI applications may likely have more. My suggestion was that an oil choice for "this application" doesn't necessarily mean anything without a specific vehicle.


See signature.

You bring up a good point though. I believe using high octane gas with quality synthetic oils pays significant dividends in these modern GDI engines. I realize every engine is different, but they have a common theme. Intake is gas free, and they tend to run higher compression ratios while recommending (often) regular octane fuel.

Higher octane = less gas dumping to prevent detonation. Add oil that has a low noack and a less disposition to cooking under high heat and I believe you are more than half way there.

I bet you if we kept details metrics of all GDI engines, along with the octane and oil used, we would find a correlation 95% of the time, 19 times out of 20
grin.gif
 
Mobile one synthetic. If deposits bother you consider a cheap homemade water injection setup. if done right you can find a hole to put a small spray nozzle in without drilling a hole.
 
Consider adding MM Oil. Water injection.Turn up the stereo when you think that pinging is starting.
 
I have read a lot of comments here and on other sites regarding GDI or TGDI engines and how to counter carbon buildup. To condense it all in one post;

Run the manufacturers specified oil and find one with low Noack, low calcium which equates to gen 2 dexos. Change that oil regularly. In other words don’t skip oil changes.

These engines like to be wound up. Take the vehicle out once a week and enjoy a spirited drive.

Use top tier fuel. I have also read and heard that using premium may help with fuel dilution of the oil. On a side note, my Mazda SkyActiv 2.5 hit the half tank mark from what the dealer filled it with. I filled it with Shell V-Power. Now, according to many here, I should not notice any difference but I did right off the bat. Better acceleration. Also, with no change in city/highway driving ratio, my mileage went from 24.2 to now 26.3. Was it the fuel? I can’t say for certain. Since this is totally non-scientific , it’s only my word against everyone else. The engine should adjust for the octane but maybe there is something here we do not understand fully.

Enjoy the new GovMo. Sounds like a real fun car.
 
Last edited:
Straight SAE 30

Amsoil has one that would qualify as a 10w-30 I believe. But it might be redline.

Run the engine hard

10w-30 and 5w-20 tend to have lower NOACK.
 
Last edited:
Originally Posted By: FlyPenFly
AMSOIL and Redline are the only ones that I'm aware of publishing their NOACK numbers. I think even Valvoline has mostly withdrawn them from their PDS. I think there are some Castrol PDS that have NOACK but those might be old formulations and not what is on shelves.

On the recent study that I saw, it's confusingly not straight forward what kind of oil can leave deposits. My only takeaway from that study was to change your top tier oil very frequently. Valve intake deposits seem to contain oil additives so it's not purely from combustion blowby. It seems oil vapor is depositing onto the intake valves themselves exacerbating the problem.

So if you want to try to minimize deposits between cleanings to maintain efficiency, reliability, and performance... the only clear thing to do in my view, is to frequently change as low NOACK oil you can find for your uses. For me, I'm planning to keep using Castrol 0w40 (which might not be good for turbo GDI due to 2k+ Ca) at 5k intervals. Redline 5w40 is 3% lower in NOACK but it's my theory that it's better to run Castrol 0w40 at 5k than Redline 5w40 at 10k in regards to valve deposits.


You're right about the Ca levels in oil. GM specifically recommends an oil with low Ca levels to prevent LSPI. I'm not sure if Ca levels contribute to IV deposits.
 
A proven oil that’s readily available would be Mobil 1 ESP. Pennzoil Platinum Euro L would also be a great option. Both are low SAPS, low NOACK oils.
 
Originally Posted By: wemay
http://www.pecj.or.jp/japanese/overseas/conference/pdf/conference12-19.pdf





Right on, good read. Thank you!

Interesting point in that document where it states low load results in incomplete full combustion which has a significant contributing factor to deposits. I suspect low octane contributes to this even more under low load conditions where fuel is dumped to prevent detonation.
 
Originally Posted By: ron17571
Mobile one synthetic. If deposits bother you consider a cheap homemade water injection setup. if done right you can find a hole to put a small spray nozzle in without drilling a hole.


I don't think this will do anything. The intake valves aren't "hot" so spraying water on them won't shock it clean.
 
Originally Posted By: webfors


You're right about the Ca levels in oil. GM specifically recommends an oil with low Ca levels to prevent LSPI. I'm not sure if Ca levels contribute to IV deposits.


Yeah, I don't think Ca levels do anything about IV deposits.

As far as though how you run the engine, I think actually running the engine hard won't reduce IV deposits. This is because it seems the most significant source of IV deposits is actually from combustion blow by. If youre running engines hard, you'll get more blow by, not less. Obviously warming up the engine before running it hard will help reduce blow by but that's just common sense.
 
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