OP back again. This thread got a new life and some interesting comments. It seems there's not solid single answer to the "best" viscosity. Wouldn't you think that if Acura believed any viscosity other than 0W-20 would damage the engine, they would have made it "required" rather than "recommended"?? I certainly do.

After our summer season was over and temps no longer in the 100's, I changed to 5W-30. Not sure if I'll stick with that next summer.

 

do you think after promising EPA certain MPG and carbon emissions they can just put language in owner manual that will get numbers bellow what they promised to EPA? They would be in big legal trouble if they did that.

 

Well, take a look at my last oil report with 5% fuel dilution and viscosity down to 6.6 https://acurazine.com/forums/3g-rdx-.../#post16863656

Still want to use 0w-20??

 

Here is 2023 Civic Type R owner manual for UK.
Same 2.0t engine, 0x-30 oil is allowed.
so please stop all the BS about “thinner” oil channels and how x30 oil is bad for your car.


https://www.honda.co.uk/cars/owners/...compressed.pdf

 

I just want to say as before that K-series are basically indestructible with reasonable maintenance, so neither thin nor thick oil will do real harm to your engines. You don't need to baby these engines, if you do, my suggestion is as russiandude, do more frequent oil change with whatever oil you choose to use.

 

Sometimes a video is worth a thousand words

 

how these videos have anything to do with Honda 2.0t fuel dilution issue that reduces specified viscosity?

 

Because the title and discussion of the thread and original topic is "Engine Oil Viscosity??" See below.

 

I liked the video. It clearly showed how much thicker 0W-40 oil is compared to 0W-20 oil at ≈70°F. But what would be very informative is to see that same test at 212°F. And to speak to RussianDude’s point, I’d like to see that same test at 212°F with fresh 0W-20 oil and with 0W-20 oil diluted with gasoline.

 

I am actually curious to find out what the oil temp actually settles at when at operating temp. I've opened the hood on my RDX after a drive on a hot day and did not feel the same blast of heat i've felt from other cars. My dad's BMW had an oil temp gauge and my last 2 Subaru's had an oil temp read out in the infotainment screen. I know the BWM would settle somewhere around 220-230. I've seen it go as high as almost 250 (midpoint on that gauge) after a highway trip. Not sure if it had an oil cooler. My last Subarus were both the H6 models and those had an oil cooler and usually settled between 195-205 with the highest i've seen being around 215. The H4s of that era did not have the oil cooler and could hit as 220-230.

 

And sometimes, they're worth none.

 

+1, shows the general flow characteristics of different oil viscosities (at the same temp). Would be interesting to see old/new 0W-20 testing, formalized oil performance testing is expensive and not trivia. Consumer Reports did it once (outsourced the testing) decades ago, but AFAIK never again. However Project Farm channel on YouTube does his own informal testing criteria which is entertaining and I do like his approach even if some of it is a bit rudimentary.


+1, same here. oil temperature is a more dynamic indication of ICE operation than water temp which is more regulated. Also shows higher engine loads which increase oil temp from friction and piston cooling (engines with underside piston oil squirters). My oldest brother has a 335i (N55) and middle brother a B6 and both temperature gauges is for the oil.

Agree, to those uneducated or uninformed a video may not provoke any words.

 

For all of you that are afraid of "5w-30" because "Honda engineers know better" or other non-sense, check out references to Mexican owner manual for 3rd gen RDX allowing 0w-20/5w-30/10w-30/0w-30 oils:

https://acurazine.com/forums/3g-rdx-.../#post16922904

 

~25 minutes long but extremely informative especially after the half way explaining oil viscosity and engine wear. Excellent video by Jason and I agree with his synopsis at the end on which viscosity to use.

 

this video is irrelevant for 2.0t honda engine that dilutes oil with fuel and lowers viscosity.
on top of that, Mexican owner manual for this car allows 5w-30.
you need to watch his another video where GM increased viscosity from 0w-20 to 0w-40 due to internal design issue. Thicker viscosity provides additional safety margin, jason does not deny it either

 

It seems you didn't watch the video, as Jason gets into the GM issues which is actually beyond design issues and includes operations of crankshaft finishing and surface treatment. It also illustrates the 0w-20 to 0w-40 is a temporary fix, doesn't solve the problem as he explains in the video with the Stribeck curves (which I knew nothing about).

And yes Honda engineers chose 5w-30 for that location, but they also chose 0w-20 for the US market. Again where I agree with Jason: manufacturer engineers >> people on the internet

 

I did watch both of his videos. He had not mentioned a single side effect of running thicker oil other than decreased MPG.
Honda 2.0t can run on multiple viscosities, but due to CAFE they are putting viscosity that gives you best gas milage in US. He later said that thicker oil can provide additional safety margin (if needed)
there is no climate difference between Mexico and Texas/Florida

Have you done UOA on this car? My viscosity has dropped by 2cSt, running one grade oil higher lets me keep oil within 0w-20 spec. The 5w-30 thins out so much that it looks like Xw-20.

Ask Jason to take a look at fuel diluter Honda 2.0t GDI

 

There's no reason for a debate if you believe that, you believe what you wanna believe
https://www.worlddata.info/climate-c...co&r2=us-texas

 

Looks very similar to me. How is your viscosity looking in UOA for this engine, or you just listening to what Jason says and trust Honda engineering?

 

You said is not "very similar". If you're gonna hyperboi, stick with it but don't backpedal.
Honda engineering >>>>>>>>>>>>>>>>> russianDude 24/7
Internet engine oil experts, they used to be a dime a dozen perhaps now down to a nickel a dozen

Foe the rest of those on this thread:
The video merely educates about motor oil viscosity and the various operating points for dynamic friction in a engine. It also gets into internal research studies Honda and Toyota did independently on low viscosity 0-20W oil on ICE engines. The best part is Jason showing the effects of changing either number and it's effects on viscosity over temp range graphs and which are acceptable and those that would potentially cause problems.

 

1. I compared south florida average temperature with Mexico, similar and often times Florida being hotter than Mexico. They are similar enough that argument about 5w-30 allowed in Mexico due to different climate is totally bogus.

2. I dont claim to be an expert, but I do send my oil to lab to measure fuel dilution and its impact on viscosity.


We are still waiting on your UOA and viscosity numbers for THIS engine, and not generalization about all thin oils. FYI: Jason is sponsored by Mobil1, and even he could not name a single side effect (other than worse MPG) from using thicker oil

 

1) So you've gone from Texas and Florida, to Florida, to now South Florida. Keep backpedaling
2) What "UOA" and "THIS engine"? what are you even writing about?
3) Proof, you didn't watch the video at all. Jason explain it at 7:50, more friction means less efficiency (MPG) and more heat causing less power.

Agree to disagree, and let's leave it at that.

 

there is a proof you did not read this thread if you are asking what is UOA and what Honda 2.0t engine does with fuel dilution.

Yes, higher viscosity causes little more heat (1-2F) and that is whats cooling system is for. This is not a downside of higher viscosity.

go ahead, think that Honda added other viscosities because mexico is such a different climate than southern states. Whatever rocks your boat. This conversation is specifically about Honda 2.0t, not some general BS about thin oils

 

The funny thing, 0w-30 will come out like 0w-20 after being thinned out by 4-5% fuel, so technically you are just maintaining 0w-20

 

1) I never claimed to have read the thread.
2) You obviously don't understand the operation of a ICE in relation to viscosity, any increase in friction causes heat which results in lower engine power and efficiency due due more losses in conversion of gasoline's thermal potential energy into ICE mechanical kinetic energy. You also have no idea how much increased viscosity increases the friction and resulting heat since it's not a constant since it's dependent on engine RPM (increasing or decreasing the sliding dynamic friction). Any increase in thermal energy for the cooling system to perform heat conversion on is less energy at the crankshaft.
3) As for your "1-2F" you just made up that number, you really don't know unless it's actually measured with various viscosities for a given ICE motor over various RPM to get different impacts to overall friction. So to just babble out 1-2F shows your lack of knowledge in the conversation. Once in the hydrodynamic region of the Strikbeck curve, that is shown on the right for increased friction for higher viscosities.
4) The only BS in conversation is yours rambling on about not understanding how motor oil viscosity affect engine operation, Jason's video is a good start.

 

why dont you provide us numbers of how much hotter oil will be in 5w-30 vs 0w-20 in RDX.
please educate us.
This thread is about RDX diluting oil with gas, which results in a 2cSt viscosity loss. The thicker viscosity is allowed in other countries for this engine which obviously does not cause issues, otherwise Honda would not list it.
You obviously have nothing useful to add to the specific discussion.

 

1) Nope, cause unlike you I don't babble out random numbers.

2) This is what the thread started as, nothing to do with diluted gas.

3)I've added a useful video resource as to how different oil viscosity affects engine operation to the thread. If you don't like Jason explaining useful information about oil viscosities, Stribeck curve and engine wear just ignore it. This thread is about "Engine Oil Viscosity??"

 

Whatever, bye

 

For those that want to have serious conversation, here is my multiple UOA. First two had 0w-20, which started out with 8.8cSt new, but ended up 6.6-6.8
The lab found high fuel dilution.
the 3rd sample had 5w-30, which started at 10.0, but finished at 7.7 which is in range of 0w-20.

I drive 70% highway, and found others having similar experiences with this engine.

 

^ I'm hoping to contribute to the data related to viscosity and fuel dilution.

I have had 2 samples done by OilAnalyzers using the oil changed by the dealer each time, which is 0w20. Both times before getting my oil changed, I smelled the dipstick and it smelled like fuel. Oil Analyzers confirmed the same ">5 - GC" on both of those reports. I changed my own oil in the spring and used 5w30, which I'll have analyzed when it's time to change out.

 

Btw, 20 viscosity range for 100C is 6.9-9.6cSt.

if you are under 6.9, its a problem

 

I don't see how my Oil Analyzers report can be correct. For my PUP 0w20 oil, they reported 8.7% fuel dilution, but the viscosity was still in range at 7.8 cSt. That doesn't seem plausible. That much dilution would correspond to a 0.5 qt increase in oil quantity, and only a trivial rise (maybe 1/10th quart) on the dipstick level was noted. New PUP 0W20 is supposedly 8.8 cSt, so there was a viscosity drop reported of 1.0 cSt.

The Blackstone results came back with near identical viscosity (7.74 vs 7.8, sample taken with an additional 800 miles on it), but only 0.5% fuel dilution reported. Blackstone doesn't use an accurate measurement method for fuel dilution, just a correlation to a flashpoint temperature. So, I don't believe either test lab wrt fuel dilution.

 

​​​​​​Oil Analyzers is the holy grail on the bitog site but I agree with you, their reports don't seem right.
The level on the dipstick has never changed between oil changes and I've never smelled gas in the oil. I had to take a quick trip to San Diego one time so nearly 900 miles of mostly highway driving. You would think if there was fuel in the oil it would evaporate off in that time. I changed the oil the morning after returning home and sent samples to both OA and Blackstone. OA said that there was greater than 5% fuel dilution and Blackstone said there was a trace.
Seeing how the level on the dipstick never changes, I'm more inclined to believe Blackstone. I don't bother with oil analysis any more and have been changing the oil at around 40-50% on the maintenance minder. I've always used Valvoline 5-30 and am using their Restore and Protect for the last 3 changes. It's supposed to clean carbon from the rings, I have no idea if it does but figure it can't hurt.

 

Following up with data.

Top two oil samples were dealer oil. Unknown miles on top, about 5500 miles on the middle row of oil. Dealer said it was 0w20.

Third sample I had switched to 5w30 when I did my own oil change. Just over 5000 miles. It's the bottom row in my screenshot. Oil dilution is lower and viscosity is great, right where 0w20 starts at 8.8 according to RussianDude.




Seems like a positive trend. I'm going to keep doing 5w30 every 5k miles.

 

Looks nice, 8.8 cST is within the range of Xw-20.

How are wear metals, iron/aluminum?

 

All seem fine? I don't really understand their color system but I'm assuming nothing highlighted is positive.

 

you Iron is trending down, the smaller number the better. It starts higher when engine is new and supposed to trend down.

 

I have a 2008 RDX that I bought with slightly over 200K miles. I've changed the oil twice, using Mobil1 5w-30, which is the recommended viscosity. A guy I know who is into cars, though he's not a mechanic, suggested that because it has about 225K, that I should run a slightly heavier oil. He suggested Mobil1 European car 0w-40, which is what he uses in his 2009 Lexus RX350 that is at almost 300K. I read somewhere on this forum that using higher viscosity oil might mess with the timing (VVT). Is this correct? The RDX is not a daily driver. In the warmer seasons, it's our camping car, and in the winter it's our snow car. Thanks in advance for replies.

 

You're missing the forest for the trees. Changing your oil only twice in 25k miles is a much bigger problem than worrying about which brand, which viscosity etc. especially with your mileage. Get that oil change interval down to 5k and then worry about the other stuff.

And when was the last time you changed your filter??

 

how did you come up with this? He already changed it twice, and now he needs to do a 3rd oil change, which is 25/3=8k miles.


0w-40 Mobil1 will work fine in your 1st gen rdx, but I doubt it will make your car last longer.

4-5k is a good time to change oil on turbo