Hey guys, we’re looking to replace our 2018 Outback; while we really like our OB, and the only issue we had was the undersized OEM battery, which was replaced under warranty.

We went to the Acura dealer, and really liked the 2023 RDX; however, I've been reading the 2.0 motor has an "oil dilution" issue?

Naturally we're concerned with paying $45K+ for a vehicle that has something we consider a major flaw. We are seniors, so most of our use is around town, etc., which I'm reading is worse, and may require more frequent oil changes?

Needless to say, we are rethinking the 2023 RDX, so any insight will be greatly appreciated.

Thank you,.......marc

 

Major flaw? My RDX has never shown any signs of oil dilution (increased oil volume on the dip-stick or the smell of gasoline in the oil, using a 7,000 mile OCI.) But if you search the forums, I think you’ll find almost every manufacturer of a DI, turbo-4 has a small percent of owners who have oil dilution. Based on what I read, driving with any boost while the engine is cold is the greatest factor in oil dilution. DI engines grossly over inject fuel when cold and boost exacerbates that problem. Drive softly while the engine is cold and the odds are high you will not see any oil dilution. How many miles are on your Outback? How long do you intend to keep the RDX? There are many owners of 2.0T Accords and current generation RDXs that have exceeded 150,000 miles with no engine problems.

Not to be an ass, but if you are worried about costs, I’d be more concerned about how Acura misleads customers with their EPA mileage expectation. The FWD RDXs will easily achieve the stated EPA fuel economy numbers or exceed them. The SH-AWD system is a “constant” system. While it is AMAZING in the corners, that system gets about 3 mpg less than the EPA estimates. If the RDX has any flaws that can hurt the wallet, that’s it. The rest of the car is excellent.

 

Modern Toyota engine does not have same fuel dilution due to their combined port and DI injection. Plenty of people posted 4-5-% fuel dilution for “normal” driving which was flagged by labs as “critical/abnormal”. Oil analysis has hard facts, use them how you like.

 

OTOH, has anyone heard of any engine failures or other problems caused by this? There are millions of cars out there with this engine. If it were a major issue I'd think we'd hear more about it.

My take...if you're worried about this, change the oil on time and keep your warranty up to date.

As Baldeagle said, the mileage is disappointing. We get about 20 mpg for mixed, around the suburbs driving...surface streets and freeway, 25+ on the highway. We have SH-AWD and run the A/C a lot. If you don't want/need AWD, it would probably be better.

 

No, not many engine failures, but not too many people have 200k miles on these engines, so we dont really know long term effects. So far so good.

 

How many miles on the Outback? Will you be keeping the RDX longer? I have seen the problem reported but haven’t seen any report of failure. I guess if it does happen down the line then it’ll lower resale value. There were enough other glitches and weirdnesses with my 2019 yet I bought a 2023.

 

https://www.sauderschelkopf.com/inve...investigation/

Anyone seen this?

 

Interesting, we always knew that this is not normal, but seems like people are experiencing issues. 5w-30 is the oil to run in these cars, period.

 

The manual calls for 0W20? That's bonkers, that's basically glorified water lmao.

 

Is oil dilution still a thing on RDX in 2024?

 

The Mexican manual for 2019 RDX says you can use 0w20 and 5w30. Link was posted somewhere here.
secondly, multiple UOA showed that viscosity of 0w-20 dropped by 2 or more cSt @ 100C. The 5w-30 is there so you can end up with something close to 0w-20 after it gets diluted. 0w-20 is CAFE thing, nothing else

 

pretty sure it is, unless there is a design change in 2.0t engine. My understanding its still same exact engine.

 

​​​0W20 is pretty crazy to me, it's essentially water when cold and like spirits when warm. I don't have an RDX yet but I like doing my maintenance at the dealer, I wonder if I can request 5W30.

 

Something about Honda GDI makes it fuel diluter. Lexus/Toyota GDI also uses 0w-20, but it does not experience the same viscosity loss as Honda.
I am not against 0w-20, but when it looks like 0w-10 at oil change -- I have a problem with it.

Unfortunately, your dealer is not likely to put 5w-30 into your car. They go by the "book" even if its bad for your car.
You'd have to do it yourself or take it independent shop.

 

0W20 is not the problem. Lots of new cars use that grade for a number of reasons, including CAFE. The oil dilution is an engine issue. Having said that, it’s not experienced by everyone. I live in Canada and make short trips and have not seen an increase in oil volume on the dipstick. That’s not as accurate as UOA of course, but this is nothing like some owners who say the oil level goes up half an inch after 1000 miles.

 

I do long drives and did not see any noticeable raise in oil level, but UOA (twice) reported fuel dilution of about 5%. Anything above 2% is considered not normal. The viscosity dropped from 8.8 cSt to 6.5 cSt. UOA is the only way to know. The use of higher viscosity is just to compensate for viscosity loss due to fuel dilution, nothing else

 

Yes, I understand. I did say that just looking at oil level is not accurate and I can certainly have oil dilution that I am not aware of. However, I have seen UOA for this car from other people that showed normal viscosity and fuel dilution numbers. So it’s not every single RDX that has this problem.

 

I guess my question for you guys is that this has been a well known issue on both the CRV forever, has this actually caused any long term issues for people? Like maybe I have my head in the sand, I am no Acura/Honda apologist, but it genuinely doesn't seem like a huge deal as I'm not really hearing/reading about major issues with the CRV or RDX as a result YET.

I could probably get around this issue with more frequent oil changes right? I have always changed oil even with full synthetic every 5k kms (~3k miles), I'm seeing most people change their oil every 10k kms based on the carfax reports I've seen.

 

No widespread short term issues. Remains to be seen what happens when these cars
start getting to 150-200k miles.

 

In fairness very few vehicles reach that kind of mileage without some sort of major engine work needed in my experience. What is the worst case scenario here? A completely new enginge or can they simply rebuild whatever components this may cause to wear?

 

Really, is this a new norm for Honda engine ? Well maintained Toyota/Lexus engines are easily getting well over 200k miles. It would be sad news for Honda engine becoming junk.
engine rebuilt is going to cost more than getting engine replaced with a used one, we talking about $5-8k and up

 

I honestly can’t speak on Toyota as I've never owned one. I've owned German, Korean, and a couple older Acura models so I guess I have a skewed POV of what is acceptable and normal for engine age. But I think you're right that it's definitely not acceptable.

Another thing I'm wondering is that I drive A LOT, like I very seldom do short trips and it isn't uncommon for me to go for 1-2 hour cruises 2-4 times a week, wondering if that will help keep the issue at bay?

 

There is a class action lawsuit for the Honda 1.5T engines and part of the issue there is safety. Some people have had cars stall while driving or go into limp mode. It’s a very small percentage. For the RDX, I don’t think it’s been long enough yet and it is a different engine after all. Like, if you are leasing the car and just want to keep it for a few years, it’s probably fine. If you want to keep it for 20 years and get 500k miles, that might be a different story. Most common recommendation is to use a slightly heavier weight oil like xw30 and change more frequently, like when the MM is at 50% perhaps. I am keeping an eye on things but am not going to get rid of my car for this reason. It has 34000 km and still drives fine.

 

I have taken (9) Honda products, mostly V-6's to about the 150k miles point. One was sold to a neighbor at about 150 k miles and he dearly wanted to get to 300 k miles but the car failed due to extreme rust in the trunk area. None of these cars had excessive oil use. A few would be down about 1/2 quart at about 5000 miles and that was generally my oil change point. I used Mobil 1 in all vehicles.

 

Honda has had a reputation of building the most reliable engine (better than Toyota), this might be coming to end.

 

In my experience.

 

The good old port injected Honda engines are not to be confused with the new GDI design.