Possible alternator replacement on a 2015 Genesis 5.0 V8.

[carguy75]

My Genesis just hit 90k miles and I think that I may have to perform my first mechanical repair on it; the alternator. Today I noticed that my car battery had only 4 volts. A few days ago it had 12.4volts when I checked it with a meter after driving the Genesis; so something have quickly drained my battery in the last few days. The battery did have a problem charging the day before it drained down to 4volts; as that it never became fully charged with my battery charger per the charger display.

I currently have my battery removed out of the trunk and is charging it with a battery charger which will also recondition the battery. I checked the battery with a battery tester after it gained some voltage(about 10v) and it passed the amperage test; so it seems that the battery can be saved.

Now I have to solve the battery drain issue. My first guess is that the alternator is not working properly and may have a bad rectifier circuit that is draining the battery at rest. The second guess could be a control module that is not sleeping at rest.

So my first step is to check the alternator when the battery is fully charged; unless the battery is just bad and never charge. I still have warranty coverage on the 950A AGM H9 Diehard battery I purchased a couple years ago I believe, but I want to make sure that the drain issue will not also kill the new battery as well if one is present.

If it does turn to be an alternator issue; then I will post how to replace the alternator on the 2015 5.0 engine. Wish me luck.

 

[JEBIV]

Just a glance under the hood of my 2012 5.0 it seems the alternator would not be terrible to replace. You might as well replace the belt at the same time.

 

[carguy75]

I

Just a glance under the hood of my 2012 5.0 it seems the alternator would not be terrible to replace. You might as well replace the belt at the same time.

I also believe that the alternator should not be too difficult to remove. I found a few videos on YouTube that show how to remove one from a 5.0 Eqqus, which seems to be a similar setup as my 2015 Genesis 5.0. The only things that seems to be needed to be removed would be the electric coolant fans(for alternator removal out the engine bay) and under body cover(to access alternator wiring connectors).

Well, my battery did charge while I was at work tonight. Now I am just letting the charger recondition the battery cells. If that is successful then I will reconnect the battery and check the alternator. Hopefully, removing the battery will "hard reset" the module that may have developed an glitch which could solve the problem if a module was the cause of the battery drain issue. Sometimes electronic devices just need a reboot to work properly. Finger crossed.

If the issue does turns out to be the alternator; then I will change my drive belt as well.

I am using an Black and Decker charger that also has a recondition mode.

 

[JEBIV]

That's a nice charger ! Where in ATL are you? I'm in Doraville

 

[skipgen]

My Genesis just hit 90k miles and I think that I may have to perform my first mechanical repair on it; the alternator. Today I noticed that my car battery had only 4 volts. A few days ago it had 12.4volts when I checked it with a meter after driving the Genesis; so something have quickly drained my battery in the last few days. The battery did have a problem charging the day before it drained down to 4volts; as that it never became fully charged with my battery charger per the charger display.

I currently have my battery removed out of the trunk and is charging it with a battery charger which will also recondition the battery. I checked the battery with a battery tester after it gained some voltage(about 10v) and it passed the amperage test; so it seems that the battery can be saved.

Now I have to solve the battery drain issue. My first guess is that the alternator is not working properly and may have a bad rectifier circuit that is draining the battery at rest. The second guess could be a control module that is not sleeping at rest.

So my first step is to check the alternator when the battery is fully charged; unless the battery is just bad and never charge. I still have warranty coverage on the 950A AGM H9 Diehard battery I purchased a couple years ago I believe, but I want to make sure that the drain issue will not also kill the new battery as well if one is present.

If it does turn to be an alternator issue; then I will post how to replace the alternator on the 2015 5.0 engine. Wish me luck.

My 5.0 alternator bit the dust at right about the same mileage - I got a charging system warning in the cluster. Must have been an easy job, as my indie mechanic sourced a BOSCH replacement & had it installed in under 4 hrs.

 

[Markymark]

Doesn't look impossible for a DIY'er - just looks like you have to drain the coolant and ATF, which seems like a bit of a hassle. See below. I hope my mechanical bits lasts longer. I'm at 97K on my 2015 5.0.

1. Turn ignition switch OFF and disconnect the negative (-) battery cable.
2. Remove the engine cover.
Page 34 of 78
3. Remove the cooling fan assembly.
(Refer to Engine Mechanical System - "Cooling Fan")
4. Disconnect the radiator lower hose.
(Refer to Engine Mechanical System - "Radiator")
5. Disconnect the ATF oil cooler hoses.
(Refer to Engine Mechanical System - "Radiator")
6. Remove the LH/RH stabilizer link.
(Refer to Suspension System - "Front Stabilizer Bar")
7. Turn the tensioner (B) clockwise and loosen, then remove the drive belt (A).

 

[carguy75]

That's a nice charger ! Where in ATL are you? I'm in Doraville

Thank you. I am in Lawrenceville.

 

[carguy75]

Doesn't look impossible for a DIY'er - just looks like you have to drain the coolant and ATF, which seems like a bit of a hassle. See below. I hope my mechanical bits lasts longer. I'm at 97K on my 2015 5.0.

1. Turn ignition switch OFF and disconnect the negative (-) battery cable.
2. Remove the engine cover.
Page 34 of 78
3. Remove the cooling fan assembly.
(Refer to Engine Mechanical System - "Cooling Fan")
4. Disconnect the radiator lower hose.
(Refer to Engine Mechanical System - "Radiator")
5. Disconnect the ATF oil cooler hoses.
(Refer to Engine Mechanical System - "Radiator")
6. Remove the LH/RH stabilizer link.
(Refer to Suspension System - "Front Stabilizer Bar")
7. Turn the tensioner (B) clockwise and loosen, then remove the drive belt (A).

Thank you.

I will pull my alternator from the top. I will only go under the car to pull and install the alternator cables since it is very hard to remove the alternator and install it with the cables connected it seems.

From what I can see in this video; it would only require removing the radiator fans and and under cover.

 

[glennk]

Is the alternator covered under warranty?

 

[carguy75]

Is the alternator covered under warranty?

I do not know, but my extended warranty coverage is over.

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[glennk]

If you bought it new or CPO, its 10/100,000

 

[carguy75]

If you bought it new or CPO, its 10/100,000

No dice. I purchased used without CPO protection. I only had the remaining 5yr/60k mile factory power-train warranty and an aftermarket extended warranty that covered the car for 4 years/100k miles. I just went pass the four year mark. I bought my car in 2018 with about 40k miles.

No biggie; it only an alternator. I have replaced a couple before on other cars. In fact; I could probably just replace the motor bushings and voltage regulator in my current one to correct the problem. However, I will just buy a new(or rebuilt) alternator and try to repair the current one to use as an spare.

 

[joegr]

Doesn't look impossible for a DIY'er - just looks like you have to drain the coolant and ATF, which seems like a bit of a hassle. See below. I hope my mechanical bits lasts longer. I'm at 97K on my 2015 5.0.

1. Turn ignition switch OFF and disconnect the negative (-) battery cable.
2. Remove the engine cover.
Page 34 of 78
3. Remove the cooling fan assembly.
(Refer to Engine Mechanical System - "Cooling Fan")
4. Disconnect the radiator lower hose.
(Refer to Engine Mechanical System - "Radiator")
5. Disconnect the ATF oil cooler hoses.
(Refer to Engine Mechanical System - "Radiator")
6. Remove the LH/RH stabilizer link.
(Refer to Suspension System - "Front Stabilizer Bar")
7. Turn the tensioner (B) clockwise and loosen, then remove the drive belt (A).

Yes, you would have to drain the coolant, but no you would not need to drain the ATF. The fluid sits in the pan which is lower than the cooler. When you disconnect the ATF cooler, only a tiny bit of ATF will dribble out (disconnect the upper one first, wait a minute, then disconnect the lower one).

 

[carguy75]

Well, just ordered a new Denso 180 amp alternator since it will take a few days to receive it. I need my car back in service so I will just swap out the old alternator and see how it goes.

The charger is still conditioning the battery; which may take a full 24hours. I will just start taking the car apart and remove the old alternator so that I can just install the new one when it arrives. I also removed my aftermarket amp and 15in subwoofer since aftermarket amp is probably causing too much of a drain on the Genesis electrical system(amp pulls 100A of current); which may have prematurely wore out my alternator. The stock alternator only puts out 180A of current;so the aftermarket amp is probably overtaxing the charging system.

The alternator I purchased.

 

[carguy75]

Correction: I cancelled the Denso alternator order because that alternator is for a 3.8; even though the Ebay seller claims it is for a 5.0 as well. Denso does not list a alternator for the 2015 5.0 model. Both the 2015 3.8 and 5.0 have different OEM part numbers; so they are not the same alternators.

I went with a higher output 250A LActrical brand alternator which is a replacement for the 5.0 alternator(part number 37300-3F020). If it works then I will reinstall my aftermarket subwoofer annd amp since this alternator should provide enough power.

 

[glennk]

Looks like it saved you $50.

 

[carguy75]

Looks like it saved you $50.

True

Plus, it will also be a stronger alternator to better handle my aftermarket audio equipment without overtaxing the stock charging system in theory.

I will also just drain the old 90k miles coolant and change the serpentine belt as well when I swap the alternator. I may also tackle the carbon on the valve stems,replace the oil pressure sensor and replace the coolant bypass tube o-ring as well; which will require me to remove the intake manifolds(upper and lower). Not sure yet. Depends on how much work is required for the alternator.

 

[carguy75]

I just confirmed that the alternator rectifier circuit is bad. It allows voltage to be pulled from the battery. To test the alternator rectifier you have to connect a voltmeter set to diode testing with one lead on the alternator positive battery terminal and one lead on the alternator case for ground for one reading and then swap the leads for the second reading.

The rectifier should allow no more than about .5mV in one direction usually with positive meter lead on the alternator case(ground) and the negative meter lead on the alternator positive terminal(B+) for one reading. For the second reading; the positive meter lead should be connected to the alternator positive battery terminal and the negative meter lead connected to the alternator case. The reading for the second test should be an open circuit; since the rectifier is suppose to prevent voltage from being pulled in from the battery.

My alternator is pulling voltage from the battery unit it goes into an open circuit. The first test voltage was about .45v, so not bad reading; however on my meter the voltage on the second test just kept climbing from .8V unitl it reaches 1 full volt and then open circuit on meter. So probably a faulty diode in the rectifier. Hence my battery drain over night. My guess is that the alternator is also putting too much AC as well. So I really do need an new alternator. I purchased my new alternator before doing this test, because I had the issue happen a couple times over the years on other cars; so I took a guess that it was the rectifier and was correct. However, I recommend that anyone else should actually test the alternator first before swapping it out since other things cause a battery drain. On open circuit is good result normally on the second test, but in my case my rectifier starts at .8V before it goes to open circuit.

Now I am waiting for the new alternator to arrive by mail to fix the issue. The space is tight so this job will be a bit of challenge for sure. I keep everyone posted.


Here is the actual second rectifier test I performed under the car. Best pictures possible due to limited space under the Genesis to work; but it should give an idea of what to expect. My advice is buy long meter leads with holding clips for this test on the Genesis. The back of the alternator that has the B+ terminal is very hard to access; but is possible reach by hand.

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[carguy75]

Well, the eBay seller still shipped me the Denso alternator by mistake. However, it seems to be a perfect match for my OEM alternator. I think that Denso fitment guide is incorrect about the 5.0 not being a match for the 210-0717 remanufactored alternator. The Denso 210-0717 is listed as an replacement for the OEM 373300-3F020 which is the 2015 5.0 alternator. However, fitment the guide has the 210-0717 listed only for the 3.8 Genesis models. So I may just keep it since i trust Denso products.

I will compare the Denso to the other aftermarket alternator(and OEM) to make sure it not a size or mounting difference on the case. In addition; I read the the higher output alternators like the LAtrical model I purchased may have a smaller pulley which means that I will need a modified drive belt. If so; then I will ship that back.

I also receive my coolant; so I will start the radiator draining soon and begin to remove the old alternator.

The Denso 210-0717 alternator.

Zerex blue Hyundai coolant

 

[carguy75]

Today I finally received the 250A LAtrical alternator and it looks exactly the same as the 180A Denso alternator. The LAtrical pulley looks to be the same size as well, so the extra amps must be from a larger coil(increased windings); not from a smaller pulley.

I am leaning more to just sending the LAtrical alternator back and keeping the Denso; however it would be nice to have the stronger LAtrical alternator to power my aftermarket subwoofer amp. So I may just keep the LAtrical. I can rebuild my original alternator(new bridge rectifier) to use as an spare if the LAtrical does fail.

I will do some additional research on the LAtrical to see if the brand is durable and put out the claimed amperes.

The two alternators side by side.