UOA for Hyundai Kona Electric, high aluminium and silicon levels

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This is not my car although I have the same model but my concerns prompted the owner to carry out an oil change and analysis at only 3,700 km for his 2021 model. The scheduled interval is 120,000 km. I changed my own at 19,400 km on my 2018 model but could not easily obtain an analysis.

The coloration of the used oil is black, almost as dark as black coffee. I'll also mention that this is a splash-lubricated single-speed 2-stage parallel shaft reduction gearbox with steel helical gears and a conventional open diff. All bearings are ball except the output shaft which uses tapered rollers. The housing is cast aluminium. There is no magnetic drain plug installed, nor any internal magnet as best as I can determine from a teardown video. The oil is a 70W GL-4.

The particulate and iron content is no surprise based on the absence of a magnet and I'm relatively certain that's also why the oil is black. This gearbox does not run hot, barely even warm. The aluminium is of great concern because IMO it indicates outer race spin. The silicon level is a mystery. Although the gearbox is conventionally vented, this particular car has not been used on dirt roads.

Technical comments welcome, please!

OzKona's analysis marked up.jpg
 
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Silicon is probably an anti-foaming agent and the aluminum is probably from a housing that was poorly cleaned before assembly.

No reason to worry until you have a worrisome trend, and a single data point is not a trend.
 
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This is not my car although I have the same model but my concerns prompted the owner to carry out an oil change and analysis at only 3,700 km for his 2021 model. The scheduled interval is 120,000 km. I changed my own at 19,400 km on my 2018 model but could not easily obtain an analysis.

The coloration of the used oil is black, almost as dark as black coffee. I'll also mention that this is a splash-lubricated single-speed 2-stage parallel shaft reduction gearbox with steel helical gears and a conventional open diff. All bearings are ball except the output shaft which uses tapered rollers. The housing is cast aluminium. There is no magnetic drain plug installed, nor any internal magnet as best as I can determine from a teardown video. The oil is a 70W GL-4.

The particulate and iron content is no surprise based on the absence of a magnet and I'm relatively certain that's also why the oil is black. This gearbox does not run hot, barely even warm. The aluminium is of great concern because IMO it indicates outer race spin. The silicon level is a mystery. Although the gearbox is conventionally vented, this particular car has not been used on dirt roads.

Technical comments welcome, please!

View attachment 80359
Document this with Hyundai as these diffs are failing early. They get dirty REAL fast and I have heard of 3 having had to be replaced already. I think these need GL-5 and not GL-4.
Hyundai AWD rear diffs get surprising dirty fast as they only have a hair under a 1/2 Qt of oil. I posted my finding in my post ohn his Youtube channel. look for Ted you cant miss my post.

This video is about the EV diff, by a Hyundai mechanic.



.
 

Kiwi_ME

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Yeah, that video is well-known among us owners but since the oil was out of a failed gearbox it wasn't immediately obvious if the dirty oil was a result, or reason for the failure.

He's a good source though and quickly answered my question about the plug torque specs, info not easily found elsewhere. Every Kona EV owner I know who has changed their oil it's similarly black. I personally believe that the black oil is solely a result of the missing ferrous particle filtering, AKA an internal magnet. Other EVs have way more sophisticated gearbox lubrication systems but that's partly because most others use the gear oil as a cooling medium between the electric motor and coolant. The Kona/Niro/Soul/Ioniq use coolant directly.

I don't see any reason why it would need a GL-5 because there are no hypoid gears present, the main reason that gear oil category exists. The Nissan Leaf has an almost identical gear reducer but has two plug magnets. There are a few videos of oil changes and the oil looks normal to me.

As for silicon v.s. silicone surely they are not related? At least Google tells me that. I will note though that one person mentioned that the analysis methods can confuse the two, but I would have thought the report would have mentioned that sort of anomaly.

But I also agree that one datapoint is not a trend and I'm not going to panic about the silicon just yet. I'll just add the vendor's comments even though they are generic and assume that this is a conventional automatic.

1638928096204.jpg

Thanks everyone so far for reading and responding.
 

Kiwi_ME

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We've just had a second report come in, this time from a Canadian owner. I haven't looked closely at the numbers yet but it has the same high aluminium and silicon. I'm assuming the odometer is 15,600 km. Unsure what ISO COE is.

Are those numbers going to be PPM, so directly comparable to the previous report?

2nd oil analysis -small.jpg
 

Kiwi_ME

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So, in summary I'm going to take control of the particle issue by adding two magnetic drain plugs, see photo. Two oil changes got the oil color back to normal. The high silicon and aluminium are going to be ignored for now because there is no obvious source for the silicon and if the aluminium is coming from where I think it is (second photo), nothing practical can be done about it. Thanks for the comments.

IMG_1625.jpeg


cross section spun bearing.jpg
 

Kiwi_ME

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It's only been 2,000 km since I refreshed the oil but I drained it out and to my surprise it's good as new. The magnetic plugs both had particle loading appropriate to the short distance traveled. I filtered the oil through an N95 face mask and put it right back in. Yes, synthetic gear oil is expensive here, this is about $38 worth for 1 litre so I'm not going to waste it if it's clean.

My conclusion is that the factory-fitted non-serviceable ceramic magnet (see photo) is too weak or in the wrong location to properly sequester the apparently-prolific generation of ferrous break-in particles by the gears. I'm going to suggest to owners of new Kona (and classic Ioniq and Kia Niro) EVs that they carry out preemptive oil changes at 2,000 and 10,000 km to clear out wear particles before they are ground down to dust by the gears, nevermind the innocent and unwary ball and tapered-roller bearings.

These useful pics were provided by an Ioniq owner in Poland who rebuilt his own gearbox to replace noisy bearings. I learned from these photos that there is an OEM captive ceramic magnet installed (yellow arrow).

One day we will be tearing apart and repairing EV gearboxes without a second thought. Note also the bronze "brush" on the input shaft tail end. That's to bleed off any voltages that conduct through from the motor shaft, a common issue with 3-phase motors driven from pulse-modulated ("VSD") electronics. The Nissan Leaf uses brushes just like an alternator, but located on the intermediate shaft.

1 with magnet identified.png
 

Kiwi_ME

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... the factory-fitted non-serviceable ceramic magnet (see photo) is too weak or in the wrong location to properly sequester the apparently-prolific generation of ferrous break-in particles by the gears.
My latest theory is that fresh wear particles are being blown off the weak internal magnet by oil windage. As particles continue to circulate throughout bearings and gears, over time they lose their affinity to stick to a magnet and make the oil black. The drain plug location for an aftermarket magnet (such as the Votex) is somewhat more protected within the threaded boss.

kona OEM magnet location.png

... The high silicon and aluminium are going to be ignored for now because there is no obvious source for the silicon and if the aluminium is coming from where I think it is (second photo), nothing practical can be done about it.
Furthermore, I now believe that particles jammed in the input shaft bearings are causing intermittent outer race spin which could account for the high aluminium in the UOA. The motor-side bearing is lightly loaded because the splined coupling is helping to support that end via the motor. The outer race is installed as a slip-fit and that's not the industry-recommended fit for light radial loads. It should be a press fit or clamped in place.

The eventual outcome is a knocking due to excessive outer race to housing clearance.

Meanwhile, it seems Hyundai have been forced to post a TSB by NHTSA due to the volume of knocking noise complaints. Reading between the lines, my impression is that Hyundai still have no idea what the root cause is.

EDIT: as owners report getting their gearboxes replaced under warranty I'm suggesting the addition of a magnetic drain plug from the start. I'm expecting that this will avoid a repeat performance.
 
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Kiwi_ME

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I'll add the latest news today, a Kona EV owner in Boston found that the OEM internal magnet in the gear reducer is non-magnetic by bravely poking a paperclip into the drain opening to reach it. He also photographed the magnet to prove it's there, the black thing in the photo. We all know that these sort of experiments don't alway end well, lol, so I wouldn't try it!

Perhaps, it's a cost-cutting move by Hyundai, but I'm accepting that this is the root cause of the dirty gearbox oil problem I've been chasing down for six months.

We've had a half dozen owner oil changes reported in the last few weeks, about 20 in total since last November. Every owner who had a magnetic drain plug installed returned clean oil, those that didn't all returned dirty oil.

I'm happy with those stats and I'm calling this done.
mboss.jpg
 

Kiwi_ME

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We just a diligent new Kona EV owner change their gear oil at only 142 km, barely out of the showroom. As reported, the oil looked tainted black initially then the original clear brown colour party came back a few days later as particles settled out. Placing a magnet on the side of the bottle attracted the majority of the particles but not all. (To reiterate, we've established that the Kona EV gearbox in OEM form has no working magnet.)

In the first photo the bottom of the bottle is not visible, that's a reflection of the side you're seeing. In the second photo it appears that some particles are not drawn to the large magnet on the right.

We know that particles are initially ferromagnetic then lose that property as they get beaten to dust by continual circulation through bearings and gears. In this case most particles seem to be in the early stages of the progression. (In my own Kona, at 19,000 km there was no appreciable volume of ferromagnetic particles left and the oil colour remained black over six months.)

Since the total running time was about 2 hours and well over half the particles were still ferromagnetic, that tells me that an internal magnet has about 1 hour to catch fresh wear particles before they are no longer attracted. Of course those particles will still cause wear to the rotating parts during that time.

Given the high level of turbulence present in a simple 2-stage gear reducer (or any diff), I would (statistically) expect every drop of oil to visit every corner of the housing interior easily within a period of 1 hour, so it may not matter much where the magnet or magnetic plug is located and there's no reason to risk placing it in an area of high oil flow where particles may struggle to hang on.

Meanwhile, I bought a new stainless steel magnetic plug to evaluate, DEEFILL, a brand that just appeared on Amazon. It's looks good quality (yes, it's Chinese made) but might be too long (5mm over the Votex) and stick out into the oil flow, but at least it will clear the diff gear. In any case I'm going to test it submerged in a bottle of oil for a few weeks hanging from the magnet to ensure that the glue isn't softened by the oil.

I had ordered two but amusingly one of the factory-sealed retail boxes was empty! Must be a new marketing idea, here's a new box, use your old plug.

Oil_after_142km.jpg
Oil_vs_magnet.jpg

IMG_1982.jpeg
 
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Most gearbox need a good break in drain/refill. Nothing in the UOA is worth worrying about. Normal break-in wear and manufacturer cleaning.

Toyota has some flush magnet drainplugs that can be used. Besides Amazon Deefil/Votex, don't forget about GoldPlug or DimplePlug.

Typical 18mm x 1.5 or M18x1.5? Common to Honda, Hyundai, Kia, Toyota...... But, OE magnets tend to be on the 'weak' side, but still pick up a bunch of magnetic particles. How much clearance is available? Some magnets can be the longer type.

Hyundai/Kia PN's:
0K95B17121
4532439000
0081017121

Toyota Pn's
10mm allen flush-magnet 90341-18021
10mm allen long magnet 90341-18035
24mm bolt flush-magnet 90341-18057 or Ford E3TZ-7A010-A
24mm bolt long magnet 90341-18040

Mitsubishi MB569390

Honda 90081-PX4-003




 

Kiwi_ME

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Yeah, at this stage the UOA with no working magnet present doesn't worry me. Later this month one owner will report back with a 10,000 km drain interval with a magnetic plug installed. A good report will confirm that there are no other underlying issues.

Thanks for tracking down those useful part numbers. I've looked through most of them and the shorter ones (Toyota app) would technically work although the Votex DP007 seems to have a slightly longer thread length (15mm) that gives me more confidence given the cast aluminium housing and my comfort level hoping nobody strips one out based on advice I provided! The longer ones would technically clear (30mm thread flange to main gear) but I'm slightly nervous about ceramic magnets hanging out in the breeze even though the Nissan Leaf does this without problem.

Some time ago I thought I had found the perfect Hyundai OEM plug and several owners ordered one from their Australian and Canadian dealers. All reported back that it was labeled as a magnetic plug but the part was not magnetic.
Hyundai 00810-17121.jpg


Another Kona owner did this, stick two disk magnets to the stock plug and it actually kept the oil clean over nearly 3,600 km.
1655254877072.jpg


On open task is to determine a suitable torque spec for the Votex because the OEM plug spec is too high, 33-44. The Votex flange diameter is smaller than OEM plus the supplied washer is thicker and softer than OEM. The number will be between 24 and 30 lb-ft, so I will have to get under the car again to refine that or hope that someone else does it for me.
 

MolaKule

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I'll add the latest news today, a Kona EV owner in Boston found that the OEM internal magnet in the gear reducer is non-magnetic by bravely poking a paperclip into the drain opening to reach it. He also photographed the magnet to prove it's there, the black thing in the photo. We all know that these sort of experiments don't alway end well, lol, so I wouldn't try it!...
Huh?
 
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The Votex I use is torqued to 35ftlbs in the 18mm thread... not at all worried about gasket thickness or flange diameter. Just torque it to center of spec.

I haven't lost a paper clip in a gearbox yet.... just other things.
 
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The elevated silicon combined with aluminium could be an indication of dirt contamination - but they could also be not related to each other ie the Aluminium is a wear material and the silicon could be sealant leaching into the oil. The ISO codes are reasonably high in my opinion confirming that the oil is indeed dirty. To have significant dirt contamination so soon I would think is unlikely, however there's a chance Hyundai are not using the cleanest of oil to start with. What's the breather setup on these like?
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