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Trusted Lifetime subscriber
Trusted Lifetime subscriber
Thanks for the info. Will have it taken back...
Here is an image of the oil on a rag. Not quite as black as the oil appears in the jar.
The Kona EV gearbox operates at around 45°C and at that temp the 75W-90 is almost three times thicker than 70W-75. I'm not sure if there is downside to the thicker oil other than poor economy but it may be specified because the pinion runs at up to 10,000 RPM.
Some Canadian owners have complained of a gear whine when cold in -30°C weather and I'm pretty sure that's due to excessively high oil viscosity. The "pour point" is around -45C, so at -30 it's like molasses.
The blackness in your oil is typical of the vast majority who have reported back, around 14 now globally. We did have one Niro owner with normal coloured oil at 160,000 km but the reason remains a complete mystery. The reason for the blackness is still not 100% proven but my next oil change at about mid-2022 will tell me if this is an ongoing problem, or the addition of the magnet has solved it.
There was even a small hint as of yesterday from the Ioniq owner with the failed gearbox that this could be an electrical discharge issue, but evidence either way is thin on the ground. The Nissan Leaf has a nearly identical gearbox design but curiously adds some sort of grounding brush on the intermediate shaft. To be continued ...
KiwiME:
On that note an Ioniq owner somewhere in Europe posted some interior photos of the gearbox a few days ago and it seems that there is a ceramic magnet secured inside.
However, the black oil is evidence of crushed steel and that in turn is evidence that the factory magnet is insufficiently large or strong enough to hold the required particle loading, so the addition of a magnetic drain plug is still just as beneficial.
Just to update this post late Feb 2022, subsequent information from the above Ioniq owner in Poland indicates that the noisy bearings in the above (classic) Ioniq gear reducer left no mentionable ferrous debris on the internal magnet.
The concern now is that the bearing damage was due to spark erosion from a voltage potential applied to the reducer from the motor. I haven't been able to get any more information out of the owner regarding a bearing teardown where proof would be found.
The motor output shaft does have a circular grounding brush but if that were compromised by even a small amount of oil or grease there could be an issue as there is no apparent backup ground. The Nissan Leaf, a nearly identical design, has a grounding brush on the intermediate shaft presumably as that shaft is essentially floating on oil films during operation. It's not clear if there is also a brush on the Leaf motor output shaft (there must be) and my questions about this on a major Leaf forum have so-far gone unanswered. I've never seen black oil come out of a Leaf gearbox from the several changes posted on YouTube. The two Leaf oil analyses I have are similarly much better than the three I have for the Kona/Niro but all show similar contamination elements: iron, aluminium and silicon.
So, at this stage my suggestion for those owners concerned is to change your oil more frequently but there is no need to add a magnetic drain plug. I'll be doing mine once every 6 months to see how it's going (and because I have a lot of spare oil) and that will give me an idea if the blackening is a persistent issue or just a result of break-in. I'd suggest once every 2 years is more than enough for anyone who wishes to be conservative, given that the warranty is only 3 years on the Kona and any failures past that will rely on the CGA backing you up. We don't see heaps of gearbox failures in the global forums but 14 out of 15 have had black oil on the first change.
An alternative magnetic plug has been identified which could be more palatable for Kona, Niro and (classic) Ioniq EV owners who rely on dealers for servicing. It's a screw-in replacement, nothing different about it.
It's a Toyota part, readily available in NZ and looks nearly identical to the stock plug. I paid $50 for one in Hastings, crazy expensive for what it is but the American-made Votex costs about the same after shipping.
I'm also more comfortable with the crimped-in magnet rather than it being glued in, even though it's the weaker ceramic type.
I've been working on this Kona/Niro dirty oil issue casually for about 10 months and will be bringing it to a conclusion with this post as I've beat it to death long enough. Here's the TL;DR of the current understanding:
1) There has been a TSB issued in the US pertaining to a Kona "motor rumble" that I can't say is definitely caused by the lack of ferrous particle sequestration. But owners should be aware of it.
2) I did some bench testing on three magnetic plug solutions (mentioned in previous posts) and concluded that all are effective.
3) Based on that, the good news is that any new Kona or Niro owner can easily deal with this themselves immediately after vehicle delivery by purchasing a packet of magnets from Mitre10, reaching under the bonnet and placing two of those strong magnets on top of the filler plug. if done at under 100 km (roughly) you won't need to worry about getting an early oil change. It's always helpful adding this later as well but I'd strongly advise getting an oil change at that time.
This photo actually shows the drain plug but it looks identical to the filler. The magnets will stay in place themselves.
Reach in where the arrow indicates, locate the filler plug and carefully place the magnets on the top. Try to avoid them snapping as they are somewhat fragile. Also, be aware that these magnets are often fatal if swallowed by children so treat accordingly.
Last week I changed the gear oil in my 4-year old Kona EV at 24,000 km for the third time. It had only been in place for 4,000 km. Because it came out black with a hint of sparklies yet again, I decided to investigate a concern that has been worrying me for some months, that the OEM internal magnet is rattling and spinning within the pocket cast into the gearbox housing. It's placed directly under where oil streams off the final drive gear, not an ideal place to leave a loose item. I'll note that the Nissan Leaf magnets mounted to both fill and drain plugs are held rigidly in place as they should be.
In the photo above you can see the pocket I'm referring to. The disk magnet is retained loosely in the pocket by a "nib" cast into the opposite side of the housing. As a result of that geometry an asymmetric portion of the magnet's top surface is open to the oil stream and it's inevitable that it will spin and jiggle around.
My initial plan was to attempt to detect the motion while driving using a Hall sensor. The first surprise was that the magnet was in a slightly different location (1 cm ->) than the photo above which is from an Ioniq, the outgoing version. The next surprise is that it was quite strong, more so than I would have expected from the ceramic variety.
While I was debating about how I can observe the output of the Hall sensor while driving without carrying an oscilloscope on my lap, I decided to see if my Jaycar inspection camera might be of help. The built-in LEDs surrounding the lens don't work well with a 45° mirror so I placed a 5mm white LED above that for illumination.
The highlights of the camera inspection is in the video below. It's a bit dull and silent but you can clearly see that the OEM magnet is easily knocked about with influence from a magnet waved around the underside of the gearbox. I spend about an hour dithering around and finally decided to glue the external magnet (stack of 3) onto a place where it seemed that it would hold the internal magnet away from the nib, the part that I think is wearing and contributing to the high oil contamination levels.
It was also interesting that this "strong" non-serviceable internal magnet held almost no ferrous debris despite having the opportunity to do so since the EV was new. It's fairly clear now that the debris is getting knocked off as the magnet rattles around, possibly even being "lathed" off by the nib as the magnet spins. The nib is at the left of the black magnet in the video, the pocket is on the right.
I'm quite confident now that this phenomenon is responsible for the unexpectedly high iron and aluminium levels we are seeing in the (11) Kona and Niro used oil laboratory analyses provided to me by helpful owners in NZ, Aus, Canada and the US.
This debris generated early on in the life of the EV, say up to 5,000 km, will inevitably be damaging the bearing raceways. The effect (documented in industrial lubrication studies) is that when encountering a particle the balls and rollers bounce over them and create a divot in the raceway upon landing.
I have no evidence that this deficiency in design is responsible for the "motor rumble / tapping / wheel of fortune" noises that are a fairly frequent cause of warranty claims worldwide but there are two factors that concern me.
1) The current root cause is thought, but unproven to be motor/gearbox misalignment. But if that was the case I would expect a failure to show up rapidly, not a year later as is happening.
2) The other factor is that the alignment is fixed by two dowel pins in machined holes. This sort of technology is bread-and-butter stuff for automotive manufacturers. It's inconceivable that an experienced automaker could mess up such a simple process in production, nevermind failing to correct it for more than a year. I think the actual root cause has eluded the makers of these EVs.
For owners, especially out of warranty, this is a concern. I have been encouraging owners of all these EVs (including the classic Ioniq EV) to get the oil changed at least once and add a magnetic drain plug if possible. It's unproven how much this reduces the risk but the fact is a gearbox is supposed to run with clean oil, that's how they work. Ferrous wear particles are supposed to be sequestered quickly by an internal or plug magnet so that they don't circulate through the bearings, becoming crushed such that they lose their magnetic attraction. There should be minimal aluminium contamination because there are no aluminum wear parts present in this design.
The motor and gearbox should be the last thing a used EV shopper should have to concern themselves with as these models enter the mid-part of their lifecycle.
Mike
I'm sure the audience size for this information is very small but just for the record regarding powertrain tapping noises that have affected a few Niros and Kona EVs over the years:
a) A mechanic in Ukraine found that the tail-end sealed and grease-lubricated ball bearing in the motor spins its outer raceway in the motor housing. That's the floating end bearing which is axially-loaded with a wavy spring, as typical for any electric motor. That creates dust and for some reason that is able to enter the bearing. This might explain why both Kia and Hyundai install a revised motor p/n when that part is replaced. Video here.
b) He also discovered that a steel cap (like a freeze plug) that seals the tail-end of the hollow gearbox input shaft fell out (!) and was getting pounded by shaft endplay. Video here.
I expect both these issues have been addressed in newer examples as there are far, far fewer tapping noise reports these days.
Meanwhile on the subject of the Kona internal round magnet, I found from the same mechanic's videos that the Kia Soul EV used a rectangular magnet that looks more sophisticated and expensive. Clearly a rectangular magnet is not going to spin. I can imagine that changing to a round one was a cost-cutting move that wasn't sufficiently validated. Video here at a frame it's visible in, or see screen capture below.
And, if that wasn't enough fun for readers who have made it this far, there's a new catastrophy lurking that is currently affecting '20+ Ioniq EVs (classic, not the Ioniq 5). The specialised low-conductivity coolant present in these is "crystallizing" in the plumbing after being changed by the dealers per the 60,000 km maintenance interval. The problem initially manifests itself as a 'low-coolant' warning, where that is determined by the smart pump motor load characteristic indicating that air is present instead of fluid. There is no actual level sensor, another cost cut no doubt.
Affected owners (about a half dozen so far in Aus and UK) have been told that there is 'no solution at this time'. For those interested the fast-moving conversation is on IoniqForum.com. I have to wonder if the dealers are flushing the systems with water as that is totally incompatible with this fluid.
But wait, there's more - the '20+ Kona, '19-21 eNiro and the Ioniq 5 also use this same coolant, however I have not seen any reports yet of this problem arising on these cars. I think the Kia EV6 does not bother with this coolant and am unsure about the latest, heavily-revised Niro EV.
It's been a year since my last post so here's an update. This pertains to these BEVs: Soul 64kWh, 28 and 38 kWh Ioniq, all 1st-gen Niro and Kona series 1 and 2. All later H/K EVs are not affected.
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