GW208

You might be right about the short trips.
We use our old car for most short little errands and the RDX for longer trips. The factory fill was right at the full mark and hadn't changed when I did our first oil and filter change at 4000 miles. It took 5.5 quarts to bring the level back to the full mark. We're at 6200 miles now and the level hasn't changed a bit, up or down. For what it's worth, I used the 5-30 Valvoline Modern Engine oil but I don't imagine that would have anything to do with the level not changing.

russianDude

interesting that you using thicker oil. I wondered that too, but due to unknowns if it will cause an issue, I dont want to risk it

leomio85

It won't. But seeing as we're in autumn going into winter, it wouldn't be prudent to use thicker oil now for us in the Northeast.

russianDude

with fuel dilution, the 30 oil might become 20 oil anyway...

leomio85

With fuel dilution, I'd be more concerned with breakdown of lubricity properties of the oil over viscosity. Viscosity is only one factor. Just try "taking the long way 'round" when taking the RDX out ... and give it the beans every so often when reaching operating temps. Hopefully it's not fuel dilution ... no matter what oil you use, it's going to cause serious issues down the road if it persists.

russianDude

my understanding that once fuel is in oil, only some of it can evaporate if you run engine at normal temperature for long time? It could be water (condensation) also. With water I think it typically evaporates...

leomio85

With it making a noticeable difference on the dipstick, I'd rule out condensation. Fuel dilution would be my guess ... or user error. No offense. Maybe when you do 5.6qts you're not quite seeing the oil level properly since the oil is so clean? Then you see it better when the oil sees more use? Just spitballing here.

If it is fuel dilution, I'm not really sure how you would remedy it. I would shorten OCI for sure. When taking the car out in the future, I'd try to get it to operating temps as much as possible. Also, deactivate the stop/start feature as much as possible, that's been pointed at as a culprit for fuel dilution (especially when the engine is still relatively cold).

russianDude

I think its related to the change in m driving patters,
more short trips. Prior Oil stayed constant when I was driving it longer. You are right, if you cant manage oil dilution — shorter OCI is needed...

russianDude

Oil level seems to stay normal, but I did a smell test, and RDX oil smell has hints of gas, not very strong, but still.... I compared the smell to my other car Lexus ES350 that is not DI engine, and it has zero smell with 4K miles on the oil.
Since I change oil myself and it practically cost me nothing, I am going to change oil at 50%

russianDude

Got Pennzoil Ultra 0w-20 from amazon for $20. Will change early. oil is so cheap.

ToniRDX19

The newer batch now is certified with API SP rating. Great for Turbocharged engine and LSPI. I bought two from Walmart and 2 from Amazon recently. Price now went back up to $43 each.

russianDude

about API SP... I got PUP 0w-20 from amazon with production date Sep29, 2020 (fresh!) but it had old label SN Plus/GF-5.

I contacted pennzoil, and they told me that PUP 0w-20 oils met SP/GF-6 on May 1st, 2020 and these are just old packaging and the oil inside indeed API SP.


Thought I share 😎


btw, pennzoil ultra 0w-20 is hard to find at good price. It has better cleaning than regular pennzoil.

Mobil1 EP is nice too, but probably not needed because I have no plans to go 15-20k miles.

ToniRDX19

Correct. The same goes for Mobile 1 Advanced Fuel Economy with the starburst logo API SN on the packaging but it is also certified as SN Plus on newer batch. The marketing stuff has not caught up with certification but the oil is. I use M1 and Pennzoil PUP between the Accord and RDX. Both are good oil. The PUP is harder to find indeed and when it goes on sale I buy in bulk. I do change my oil frequently. Last oil change was at 60% oil life. We are not driving much these days and I do drive locally more often.

I get better MPGs with PUP compare to the M1 AFE full synthetic.

tuna piano

I used to subscribe to the "last drop contains the most contaminants" school of thought and wait for a long time before reinstalling the drain plug, until I realized it probably doesn't matter.

One day a mechanic friend of mine pointed out that anything short of tearing the engine down will leave a substantial amount behind. In the case of the RDX, it looks like that quantity is 1.2 quarts, or a good 20% of total capacity.

If you're warming up the engine to suspend and homogenize the contaminants, there's no telling where the theoretical "worst" of the contamination will be when you start draining--probably has something to do with relative specific gravity, turbulence from engine last gasp, and pure merry-go-round timing. It's very possible that the worst of the contaminants are in some nook or cranny somewhere that a single gravity drain won't be able to remove.

Bottom line, the last few drops undoubtedly remove more contaminants, but the difference is probably not very significant compared to the 20% of oil that is still somewhere in the engine. These days, if I am doing a gravity drain, I wait until a slow drip, maybe something like 1 every 2 seconds or so. Using quality oil and keeping up with the change frequency should keep those leftover contaminants at a controlled level, and I have faith the engineers accounted for that in the OCI.

russianDude

More frequent oil change is not a bad idea
if oil smells like gas

tuna piano

Oil having a strong gasoline odor would definitely pique interest. Probably worth $25-$30 to get a used oil analysis done to determine the level of contamination from fuel, antifreeze, TBN, wear metals, etc.

russianDude

I was going to try blackstone labs, but there are some discussions on bobistheoilguy that their fuel dilution is not accurate and you need different lab.
RDX being DI engine will have some fuel dilution if you make short trips

tuna piano

Good old BITOG, plenty of sharp minds there for sure. Over the years I have seen some dissent around Blackstone Labs results, though if they have consensus doubt around the fuel contamination level, that would be a clear yellow flag. It's interesting because ironically, BITOG might be the closest thing to a governing body to keep the oil analysis outfits in check. The thing is, they are not organized for that, and as with any public forum, the loudest voice is not always the most credible one.

Still though, it is an instrumented test with a valid indicator (something similar to PPM or parts per million) that could at least provide some quantitative value--most likely better than going by sight, touch, or smell.

At the end of the day, if the oil's vitals are holding up and any contamination is not causing any tangible problems, it's probably okay to continue to follow the owner's manual and enjoy the ride. It will always be easy to find problems when one goes looking for them.

vkamnyev

I just did my first oil change at 4,800 miles via the pump extraction method. I also didn’t jack up the car but rather backed into my garage and then drove up slightly on the ramps. The garage floor is sloped about 5 degrees and . This kept the vehicle level and allowed enough space for me to crawl under, remove the metal plate and get to the filter. About 3000 out of the 4800 miles were what I would consider “short trips”. Keeping the fuel dilution issue in mind since purchase, I made sure we drive the car more aggressively on longer trips to allow for burn off of any fuel that might be in oil. With this said, my extractor still got about 5.3qt out. All in all a pretty easy oil change but I did have to go to Autozone when I got to changing the filter... the factory filter wouldn’t budge by hand... so for the first time in 10 years of changing Honda oil, I had to get an oil wrench. Next oil change should be 20 minutes.





5 dollar wrench will save my wrist next time

russianDude

I also changed oil at 50% MID (4k miles) due to short trip and some smell of gas. I left old filter, it took 5qt exactly.
I recommend mobil1 oil filter m-110a.

tuna piano

Thanks for this info. I had been wondering how much an extractor would remove. By any chance did you remove the drain plug to see if any was left behind?

vkamnyev

I didn’t try to remove the drain plug. I came to trust the extractor method by doing oil changes on my Audi A4 and it consistently provides good results in my opinion. I put exactly 5qt back, as suggested by the manual, and the reading is at full mark (after taking it on a drive and letting it sit). When there isn’t a foot of snow on the ground, I find that using the extractor turns this into a pleasant activity rather than a chore; plus there is less mess

tuna piano

Gotcha. Something to consider though--I've found my extractor produces varying results from car to car. It has worked well with pretty much all the German cars. In fact, with my old E39 540i, after using the extractor I removed the oil pan (I was replacing the gasket) and found that the extractor could actually remove more oil than the drain plug, because dipstick tube aimed the extractor hose into a recess in the pan that was lower than the drain plug hole.

On the other hand, I've had various Japanese and Korean cars where the extractor couldn't remove more than about 2 quarts, sometimes even less. It seems to be based on the location of the dipstick tube and shape of the oil pan. This is why, on the first oil service, I usually try the extractor and then remove the plug on the first try to see what I'm leaving behind.

Given how much you were able to get out of there, there probably wasn't much left at all. Almost certainly not enough to worry about, since there is a good bit of oil left in the engine even after a full drain based on the difference between total capacity and change volume. I was just curious.

russianDude

I think for some german cars extractor is actually a preferred way done in dealership, maybe thats why its optimized for it.
I do the old school way, its really simple. With experience you will have less mess each time. I leave it drain for 30-40min

leomio85

Not the preferred way, but actually designed way to do the oil change on German vehicles. From what I've heard, even from dealer techs, is that the extractor doesn't do as well of a job as the old fashioned oil drain plug, but it makes servicing much easier, especially since most have their filters on top now (for the very same reason). I don't know, just what I've been told. I've never owned a German vehicle, nor have I ever used one of those extractors. That being said, longevity hasnot been the mission statement of any German automaker in the last two decades.

vkamnyev

I was looking at how the oil pan is designed and if the dip stick goes directly to the shallow area, I would say that the difference would be insignificant. In my A4, in order to get to the PLASTIC drain plug, I have to take off the plastic undercarriage that is held by 18 fasteners of 5 different types ( I think... but if not, it’s pretty freaking close). With that said and with the filter being on top, the pump just makes so much sense there.
just for the kicks, I will do the traditional method on the RDX the next time and then will put the pump tube in and see if there was anything left.

russianDude

Does extractor work with hot oil? From what I read is that oil drain is better on a hot engine, and thats how I do it. No, I dont burn my fingers 😀

vkamnyev

Warm/hot oil obviously flows better and the extractor plastic does withstand high temps. However! The key here is to bring the car up to operating temps and then let it sit for 20 minutes to allow the motor to cool off. I’ve seen horror stories where people just go straight to inserting the tube in a hot engine... what happens is the worst nightmare for the DIY’er and the plastic tube just melts to the dip stick opening and/or oil pan itself.

Showkey

Another data point on the oil level and capacity.

2021 with 6000 miles 2/3 of the miles were highway miles. First oil change done early and habit and slight fuel smell.
Drained the oil and filter.......measure the oil quantity found 5.75 qts.

Prior to the changed had been watching the oil level on the dip stick on the RDX........found no real issue. As a prior owner 2017 CRV is was well aware of the oil dilution. My CRV had a pretty consistent dilution issue in cold weather. At the worst mine would be over quart high on the stick. Honda did multiple free oil changes as many of us waited for the fix. Honda did the product update to the CRV which improved the situation but was not a 100% cure. Honda extended the engine warranty in a settlement with all owners. Mine never had had any issues other than the level increase. No check engine or other symptoms.
The CRV on cold winter days ( 0* to -15*F) you could watch the engine temperature drop at stop lights. 1.5T just could have been air cooled....it just did not develop enough heat to hold temperature at idle. Under way the temperature would return to normal levels. My thought this played a part on the CRV problem.

Unfortunately just before the RDX change I did not check the stick level. But again drained quantity was 5.75 qts
Add 5 qts of Mobil 1 0w-20 new filter and start the engine ran a couple of minutes found it .75 qts low on the stick. ( on level ground)
Went for 10 mile test drive and returned check the oil on the stick after 5 minute of sitting .......found just slightly low of the middle point on the stick. ( A-B marks on the stick)
Checked the oil several more times as it sat for 15-45 minutes. Maybe moved up the stick slightly but still just half way point.
Added a 1/2 qt let it sit and rechecked.......just slightly below the top top mark.

One trick on the dip stick.........rub the orange plastic section witha scotch brite pad to scuff the plastic. It roughens the plastic just enough to better see the oil level on the stick by breaking the surface tension. Just scuff and wipe clean.

So first seeing the extra oil in the drain pan, was thinking CRV a issue........then reading this thread........and refilling 5.5qts..........I have no current concerns that I have any oil real oil dilution issues.

I have no idea why the manual says 5.0 qts with filter.
My ‘19 Ridgeline has no such inconsistencies. 5.7 qts and it hits the top mark every time.
Beginning to think 5.7 qts might be a better spec for the RDX.
The CRV 1.5T had 3.7 qts which is the same as many Honda motorcycles......seems like it could have used more oil ?

5 qts added After test drive wait 5 minutes:


oil level after 5.5 qts added


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