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I changed my oil at home after the dealer hand waved the fuel dilution issue away. It was hard to be precise because I was measuring the old oil using empty oil containers, but I got between 6.5 and 7 L of fluid out of the engine. It took just over 5L to reach the full line again. Extreme dilution. When I came back inside my wife said I reeked like a gas station. It also looks like the valve cover gasket is seeping oil now. 34,000 kms.
I've read that also, I have an extra Blackstone kit and will send a sample to both labs so we can see just how much different the results might be. It will be another couple of months though before an oil change is needed.
I've been using Valvoline 5-30 from the first oil change.
We received our oil reports back and there is quite a difference between them as far as fuel goes. I think I like the Blackstone one better.😀
This was with 4650 miles on the oil and the MM at 30 percent. Most of our driving is on longer trips with fewer short in town driving trips, probably about an 80/20 mix.
These samples were taken after 2 back to back 200 mile freeway drives. The oil level has never changed and I've never noticed any gas smell from the oil.
We received our oil reports back and there is quite a difference between them as far as fuel goes. I think I like the Blackstone one better.😀
OilAnalyzers gives more accurate fuel dilution measurement than blackstone, they use more accurate test. You can find explanation on BITOG.
If you look at your viscosity at 100C, its very close between two reports 8.62-8.7. Both labs are accurate in this number. This is a big drop for 5w-30 valvoline. When it was new, it had a starting viscosity of 10.6. The resulting viscosity of 8.62-8.7 is in the same range as 0w-20 oil viscosity. Mobil1 0w-20 EP has starting viscosity of 8.8 as an example. (if hypothetically dealership said you used wrong viscosity, it would be impossible for them to do so from the oil analysis). The only reason your viscosity dropped is because of fuel in oil.
Also, your TBN started getting low even only after 5K miles, you made a good call to change it.
My results are consistent with yours. These engines are fuel diluters (even if you drive highway). My new regiment is to buy cheapest 5w30 and change it twice throughout the MID cycle, ie 50% and 0%. I recently bought couple of cases of Kirkland 5w-30 at costco on sale. It was $16 for 5 quart, says Full Synthetic latest API SP and also Dexos gen3 approved (Dexos is even more stringent requirement on top of SP). I do my own oil changes, so its a very quick task for me.
Last edited by russianDude; 05-20-2023 at 06:19 AM.
OilAnalyzers gives more accurate fuel dilution measurement than blackstone, they use more accurate test. You can find explanation on BITOG.
Thanks for the detailed reply. From reading your posts here and on BITOG and the explanations of the test procedures I was expecting to see a significant difference.
If I'm reading the reports right, the base number from Blackstone was 3.3 and Oil Analyzers has it at 2.48. That seems like quite a big difference and I was surprised to see that.
Have you seen the same spread in your reports, I don't remember reading anything about a big gap in the base number readings between the 2 labs.
Thanks for the detailed reply. From reading your posts here and on BITOG and the explanations of the test procedures I was expecting to see a significant difference.
If I'm reading the reports right, the base number from Blackstone was 3.3 and Oil Analyzers has it at 2.48. That seems like quite a big difference and I was surprised to see that.
Have you seen the same spread in your reports, I don't remember reading anything about a big gap in the base number readings between the 2 labs.
I never had same sample in two labs. TBN 3.3 and 2.48 are close enough, but yeah, kind of a big margin of error. You never want to drive under 2TBN, so oil change at 2-3 is a good time.
Hey guys, we’re looking at a 23 RDX, and I just stumbled across this thread. Naturally I’m concerned, and rethinking the RDX. Do the 23’s still have this issue?
Hey guys, we’re looking at a 23 RDX, and I just stumbled across this thread. Naturally I’m concerned, and rethinking the RDX. Do the 23’s still have this issue?
thank you,…….Marc
I am sure they do, same engine. Its pretty much common occurrence on all Honda 2.0T and 1.5T engines. We dont see massive engine failures, so somehow it seems to work fine with this much fuel in it.... Just makes me nervous, especially when anything over 2% by auto industry norms is considered "abnormal".... You can run thicker oil, or as most members dont give a damn, and run 0w-20 and their engines still work fine...
5w-30 kirkland. Fuel above 5%, viscosity dropped a lot for 5w-30.
same driving patterns. This is a proof that I need to run 5w-30.
0w-20 viscosity when new is like 8.6, but I am down to 7.7.
That’s why we should use oil with higher viscosity !!!
Knowing about that gas dilution issue from the very beginning - I’ve started to use 5w30 viscosity oil and don’t have any problems with dilution … that fairy tales about thin channels in the engine block that does not provide proper oil circulation is just a myth … using 0w20 in turbo engine with direct injection is a crime
Knowing about that gas dilution issue from the very beginning - I’ve started to use 5w30 viscosity oil and don’t have any problems with dilution … that fairy tales about thin channels in the engine block that does not provide proper oil circulation is just a myth … using 0w20 in turbo engine with direct injection is a crime
5w-30 does not help with fuel dilution (did not help in my case), but it mitigates viscosity loss due to fuel.
Honda has a bad GDI design, toyota uses direct injection and port injection combined in their modern engines that do not this dilution issue.
Thanks for the update. I don't know how cold, cold is. I do get to see 20-30s for a few weeks and ultimate lowest could be like 10-15 over night etc. I do not have a garage and it will be parked outside.
the problem can start up because low viscosity oil that officials provide cannot effectively lubricate the engine parts (especially in difficult operating conditions ) - and under some circumstances -because of that oil rings on the pistons fail - and gasoline gets into oil ( especially if you change motor oil once in 7500 miles - it becomes the water ) … besides, we also should investigate how does the gas itself ( as example - that containing ethanol) may cause such dilution problems - I wonder what type of gas did the problem car owners used ? As we know - the regular gas does not recommended to use in turbo engine - better choice is high octane gas instead - it burns in cylinders more effectively and cause much less detonation ….
the problem can start up because low viscosity oil that officials provide cannot effectively lubricate the engine parts (especially in difficult operating conditions ) - and under some circumstances -because of that oil rings on the pistons fail - and gasoline gets into oil ( especially if you change motor oil once in 7500 miles - it becomes the water ) … besides, we also should investigate how does the gas itself ( as example - that containing ethanol) may cause such dilution problems - I wonder what type of gas did the problem car owners used ? As we know - the regular gas does not recommended to use in turbo engine - better choice is high octane gas instead - it burns in cylinders more effectively and cause much less detonation ….
Not sure where you're getting your information, but it is incorrect regarding fuel. The only time higher octane fuel will prevent detonation is when you're pushing the engine to its limits, however, if you're on a long road trip, you're better off with regular fuel.
Not sure where you're getting your information, but it is incorrect regarding fuel. The only time higher octane fuel will prevent detonation is when you're pushing the engine to its limits, however, if you're on a long road trip, you're better off with regular fuel.
well, in your car manual you can find the gas requirement - premium … it is because that turbocharging increases the compression heat, so that can raise the peak combustion temperature and increase the likelihood of detonation occurring. Most turbocharged or supercharged have lower static compression ratios to keep the total compression heat from rising too much, require the use of high octane gasoline (more resistant to knock/detonation). Driving the road on high speed proceeding turbocharger to blow - that’s rise knock factor greatly … If your engine is designed for high octane gasoline/petrol, and you use a lower octane gasoline, the engine computer will retard the timing, degrading engine performance, to try to avoid knocking/detonation. You'll get reduced power and worse economy.… so - as the regular gas not so effective - might be greater amount of in should be used during the cycle, and more unblown leftovers of less effective gas are removed from the surface of cylinder thereby increasing mass fraction in oil. this reduces the properties of the oil and leads to wear of the oil rings as a result, which in total only increases the mixing of gasoline and oil together
well, in your car manual you can find the gas requirement - premium … it is because that turbocharging increases the compression heat, so that can raise the peak combustion temperature and increase the likelihood of detonation occurring. Most turbocharged or supercharged have lower static compression ratios to keep the total compression heat from rising too much, require the use of high octane gasoline (more resistant to knock/detonation). Driving the road on high speed proceeding turbocharger to blow - that’s rise knock factor greatly … If your engine is designed for high octane gasoline/petrol, and you use a lower octane gasoline, the engine computer will retard the timing, degrading engine performance, to try to avoid knocking/detonation. You'll get reduced power and worse economy.… so - as the regular gas not so effective - might be greater amount of in should be used during the cycle, and more unblown leftovers of less effective gas are removed from the surface of cylinder thereby increasing mass fraction in oil. this reduces the properties of the oil and leads to wear of the oil rings as a result, which in total only increases the mixing of gasoline and oil together
Sorry, you're listening to too many folks who don't have a clue what they're talking about; the fact is, premium fuel is an absolute waste, unless you are doing regular full-throttle pulls. As for what the Owner's Manual says, you need to read it again (assuming you ever read it in the first place), it absolutely does NOT say premium gas is required.
Sorry, you're listening to too many folks who don't have a clue what they're talking about; the fact is, premium fuel is an absolute waste, unless you are doing regular full-throttle pulls. As for what the Owner's Manual says, you need to read it again (assuming you ever read it in the first place), it absolutely does NOT say premium gas is required.
for you to know - the manual provides the information about 91 or higher grade petroleum requirement. According to the official site information energy.gov ( department of energy of USA) - the 91 and higher octane is a premium grade gasoline. Nevertheless you can prefer to use wherever you want instead - on your own risk - but don’t be upset when some engine trouble will happen. Some people says that engine can operate even on vodka, so don’t be shy to experiment )
Manual states that 93 recommended, but minimum required octane is 87.
anyway, I fail to understand how octane relates to fuel dilution, I did use octane 93 top tier gas and fuel dilution is horrible
for you to know - the manual provides the information about 91 or higher grade petroleum requirement. According to the official site information energy.gov ( department of energy of USA) - the 91 and higher octane is a premium grade gasoline. Nevertheless you can prefer to use wherever you want instead - on your own risk - but don’t be upset when some engine trouble will happen. Some people says that engine can operate even on vodka, so don’t be shy to experiment )
Clearly English isn't your first language, and if it is, well, you need a refresher.
Do you guys smell oil/gas smell in cabin for the folks that deal with oil dilution? Reason I’m asking is that I know a rdx had bad oil or gas or exhaust smell in cabin with 1200 miles. It was bought in february Ny weather 2021. Less than 10 miles trip mostly city driving. Warmed car 10 minutes before use. Lot of honda show up when you google this issue. Acurazine has a thread about rdx regarding this problem. This rdx had nasty smell during summer while parked outside. This happened in 2021. They don’t have it anymore. Problem started before 1st oil change. Dealer didn’t help. I’m looking to lease one. Don’t know if the smell was due to oil dilution or any other issue. Typically dilution should’nt be a problem in summer time. Can oil dilution cause smell in cabin?
No smell in mine, but my levels were about 5%. Maybe if you have some crazy high levels you could smell some…
Thanks for the reply. I’m being cautious. Always used 93 gas. Warmed 10 minutes before use. Up to 10 miles trip mostly city. Smell was bad during summer even after oil change. That’s why I’m wondering if oil dilution causing the smell or it’s a separate problem. When I googled this issue lot of people had similar issues with other hondas.
Thanks for the reply. I’m being cautious. Always used 93 gas. Warmed 10 minutes before use. Up to 10 miles trip mostly city. Smell was bad during summer even after oil change. That’s why I’m wondering if oil dilution causing the smell or it’s a separate problem. When I googled this issue lot of people had similar issues with other hondas.
Warming the engine up before use is a textbook way of causing oil dilution; your best bet is to start the engine, click on your seatbelt, and drive away.
Warming the engine up before use is a textbook way of causing oil dilution; your best bet is to start the engine, click on your seatbelt, and drive away.
Interesting. I thought you have to warm the engine up to optimal temp and don’t shut off the engine right away after the trip for turbo longevity. Then again you have to warm the car for heat in the winter. Like I said before the car had same stench even after the oil change in summer. Let say if the car was parked outside in the sun the smell was nasty. That’s why I was wondering the smell could be do to dilution or other issue. I see majority of the people in this forum does not experience this. Thank you.
Warming an engine up at idle is always harder on the engine and the oil than starting the engine, giving it a few seconds, and then driving away. Always.
This thread has a lot of good information. I suspect minor fuel dilution on mine, I've been closely monitoring the dipstick and notice the level rises slightly after short trips, after long trips the level goes down a bit, but it's still a hair higher than when I initially filled it at the last oil change. I check oil level after the car is fully cold as it's easier to read the dipstick.
After seeing other oil analysis results here, I don't think I need to spend the money on one myself. Looks like a good plan is what @russianDude has already said: change just the oil at 50%MM and then change oil and filter at 0-5%MM with 5W30 (it will thin down anyways).
This thread has a lot of good information. I suspect minor fuel dilution on mine, I've been closely monitoring the dipstick and notice the level rises slightly after short trips, after long trips the level goes down a bit, but it's still a hair higher than when I initially filled it at the last oil change. I check oil level after the car is fully cold as it's easier to read the dipstick.
After seeing other oil analysis results here, I don't think I need to spend the money on one myself. Looks like a good plan is what @russianDude has already said: change just the oil at 50%MM and then change oil and filter at 0-5%MM with 5W30 (it will thin down anyways).
Great find about Mexican manual! This once again proves that 0w-20 was put in US manual purely due to government CAFE requirements.
even in US manual it uses words like “recommended viscosity”, does not say “required”
Great find about Mexican manual! This once again proves that 0w-20 was put in US manual purely due to government CAFE requirements.
even in US manual it uses words like “recommended viscosity”, does not say “required”
use 5w30 without fear and sleep good at night!
I'm curious with 5w-30 if it's safe to run maintenance minder down to 15% to change the oil and filter then vs doing an extra change at 50%. From your oil analysis reports it looks like the oil gets diluted with fuel early and then hits a steady state, it doesn't get worse with more miles, with 5w-30 it would still stay in grade of a 20wt.
I'm curious with 5w-30 if it's safe to run maintenance minder down to 15% to change the oil and filter then vs doing an extra change at 50%. From your oil analysis reports it looks like the oil gets diluted with fuel early and then hits a steady state, it doesn't get worse with more miles, with 5w-30 it would still stay in grade of a 20wt.
You are correct that fuel dilution usually (not always) happens early on (first 1000 miles?) and then it gradually stabilizes around certain percentage. However, oil analysis is expensive $35 and you would need to oil sample your oil every 1000 miles to know what's happening. No one will spend that much money when you can buy new oil for $20.
Back to your question: Using 5w-30 will be more beneficial even if you only change it as per normal MID cycle. However, if you want the maximum protection (and have time and resources) for your GDI turbo that is a fuel diluter, you should change your oil every 3-4K miles regardless of MID schedule. I am DIY. I dont change my oil filter with every oil change (no need because oil gets changed every 3-4K miles). I get $20 5w-30 5qt Kirkland at Costco, 10min in my garage and I am done and dont have to think about it.
You are correct that fuel dilution usually (not always) happens early on (first 1000 miles?) and then it gradually stabilizes around certain percentage. However, oil analysis is expensive $35 and you would need to oil sample your oil every 1000 miles to know what's happening. No one will spend that much money when you can buy new oil for $20.
Back to your question: Using 5w-30 will be more beneficial even if you only change it as per normal MID cycle. However, if you want the maximum protection (and have time and resources) for your GDI turbo that is a fuel diluter, you should change your oil every 3-4K miles regardless of MID schedule. I am DIY. I dont change my oil filter with every oil change (no need because oil gets changed every 3-4K miles). I get $20 5w-30 5qt Kirkland at Costco, 10min in my garage and I am done and dont have to think about it.
So you dont think the filter gets contaminates from the fuel? Just like water will do?
So you dont think the filter gets contaminates from the fuel? Just like water will do?
It does, Filter holds what 0.4 qt per manual. Assuming 5% of 0.4 qt is fuel, if you replace 4.6 qt, the overall will be very low fuel dilution, 0.4% if I did my math right. 0.4% is fine. If you have time & resources changing filter is also good.
Last edited by russianDude; 01-23-2024 at 12:09 PM.
It does, Filter holds what 0.4 qt per manual. Assuming 5% of 0.4 qt is fuel, if you replace 4.6 qt, the overall will be very low fuel dilution, 0.4% if I did my math right. 0.4% is fine. If you have time & resources changing filter is also good.
I can't find the dry fill oil volume on this engine, but most have the best part of a quart of non-drainable oil, in addition to that in the filter. So maybe 6 quarts total oil in the engine. So even if you do change the filter, 5% fuel in the oil will only be reduced to about 0.8% after the oil change.
In general, they say anything over 3% is elevated,
and over 4% is considered excessive. So anything you can do to bring it down when its over 5% is good.
Got my UOA back at 5100 km and 0w-20. Fuel dilution was 6.93% and viscosity was down to 6.33 which is basically on the low end of a 0w-16 oil. No rise on the dipstick. If it wasn’t for testing, I would never have guessed it was this bad. I am going to change the oil again at 3000 km and see if that makes any difference.
Got my UOA back at 5100 km and 0w-20. Fuel dilution was 6.93% and viscosity was down to 6.33 which is basically on the low end of a 0w-16 oil. No rise on the dipstick. If it wasn’t for testing, I would never have guessed it was this bad. I am going to change the oil again at 3000 km and see if that makes any difference.
from my experience and others, fuel dilution happens fairy quickly after oil change, and then it levels out. You might find out the same result after 1000km. Ive said this before, but you better off using 0w-30 because it will thin out to 0w-20 ranges. Also, Mexican owner manual for this car allows Xw-30, so its nothing to worry
Yes I know. I already bought 0w-30. Just waiting for one more UOA to see how bad things are at half interval. Even with 0w-30 I might change it at 3000 km instead of 5000 km.
Hi Folks, old forum member here (first joined when we bought a 2015 RDX Tech) but recently got a low-mile 2019 A-Spec. Also shopping a 2021 RDX Base or Tech for business use. On the fuel dilution issue - which was already concern when I had a 2018 Accord 2.0T - with the recent posts here about oil analysis reports and TBN, I looked up TBN additives and found 3 on Amazon. Apparently, TBN boosters are commonly used for diesel engines due to diesel fuel's high sulfur content. I'm thinking, with one 3rd gen RDX and possibly another one coming, I might use these boosters (ex: $29.60 for a 32 oz bottle) as a safety measure. Has anyone here used or considered using this additive?
The issue with fuel dilution is reduced viscosity. I don’t know anything about these additives but how would they help with that? As far as I know, this has nothing to do with sulfur, right?
03-04-2023, 11:11 AM
