0W30 vs 0W40

Joined
Jun 30, 2018
Messages
20
Location
Arizona
I bought a 2021 Sonata as my new daily last year. 2.5T Smart Stream engine. It suits my needs in a daily driver. Owner's manuals says nothing but 0W30. Been using Mobil 1. Did an analysis at 27K. Oil and engine immaculate. I used Penzoil Ultra Platinum 0W40 in my previous daily. That engine was also immaculate at 100K when it was totaled.
I'm in Texas and moving back to Arizona in the spring. Both have summer weather temperatures at 100+ of course. 0W30 is rated at -35 to 86F. 0W40 up to 104⁰. I'm thinking of going back to 0W40. Good idea? I'm not overly concerned with Hyundai saying is specifies 0W30 only, considering they're allowing dealers to use 0W20 during the free maintenance. You'd think they'd be stricter with that considering the Theta II issues ..
 
I bought a 2021 Sonata as my new daily last year. 2.5T Smart Stream engine. It suits my needs in a daily driver. Owner's manuals says nothing but 0W30. Been using Mobil 1. Did an analysis at 27K. Oil and engine immaculate. I used Penzoil Ultra Platinum 0W40 in my previous daily. That engine was also immaculate at 100K when it was totaled.
I'm in Texas and moving back to Arizona in the spring. Both have summer weather temperatures at 100+ of course. 0W30 is rated at -35 to 86F. 0W40 up to 104⁰. I'm thinking of going back to 0W40. Good idea? I'm not overly concerned with Hyundai saying is specifies 0W30 only, considering they're allowing dealers to use 0W20 during the free maintenance. You'd think they'd be stricter with that considering the Theta II issues ..

You might want to send a PM to a member here named AeHass, hope I spelled it right.
 
I bought a 2021 Sonata as my new daily last year. 2.5T Smart Stream engine. It suits my needs in a daily driver. Owner's manuals says nothing but 0W30. Been using Mobil 1. Did an analysis at 27K. Oil and engine immaculate. I used Penzoil Ultra Platinum 0W40 in my previous daily. That engine was also immaculate at 100K when it was totaled.
I'm in Texas and moving back to Arizona in the spring. Both have summer weather temperatures at 100+ of course. 0W30 is rated at -35 to 86F. 0W40 up to 104⁰. I'm thinking of going back to 0W40. Good idea? I'm not overly concerned with Hyundai saying is specifies 0W30 only, considering they're allowing dealers to use 0W20 during the free maintenance. You'd think they'd be stricter with that considering the Theta II issues ..
Depends a little on what part of AZ. Down around Phoenix and Scottsdale right now I lean towards the 0W 40. But Flagstaff more towards the 0W 30.
 
Depends a little on what part of AZ. Down around Phoenix and Scottsdale right now I lean towards the 0W 40. But Flagstaff more towards the 0W 30.
Tucson. I moved out there in 2018 but came back to the Dallas area in 2020 to be closer to family with the COVID nonsense.
 
Personally in the heat of summer in AZ, I'd rather use a 0w-40. Perhaps if your oil changes align right, switch back to 0w-30 for winter.

I've seen too many owners manuals in the US call for thin oils, when the same manual in another country offers higher grades for higher temperatures. But then again, I've seen countless engines run to 200K+ on thin oils like 0w-20, etc. Most people will never wear an engine out (other than lack of maintenance or manufacturer defect); some other failure in the car is what usually sends it to the graveyard.

So I can't really make a judgement one way or the other and you're probably fine either way. I just have my personal preferences.
 
Of course not. That's what I searched and that's why I came to ask here. I don't have a bottle of it on hand to read, and every picture of the bottles I found online gets to blurry when I try to zoom in on them.
Consider the source of your search results. I too see that an article on www.repairsmith.com provides that temperature range for 0w30, but doesn't seem to cite the source. Mobil doesn't appear to specify a maximum ambient temperature for their basic 0w30. Ambient temperature ranges are generally specified by the equipment manufacturer (Hyundai), and in your case you state the manual calls for 0w30, full stop. Other vehicle manuals call for a change in oil grade based on temperature, usually with a large overlap. This doesn't seem to be the case for your vehicle.

If you want some peace of mind, run a good quality 0w30 for a short interval (5000 miles as a bit of an arbitrary number) once you're back in Arizona, then have an oil analysis done. When you get the results back and they show nothing of concern, you can rest comfortably.
 
Consider the source of your search results. I too see that an article on www.repairsmith.com provides that temperature range for 0w30, but doesn't seem to cite the source. Mobil doesn't appear to specify a maximum ambient temperature for their basic 0w30. Ambient temperature ranges are generally specified by the equipment manufacturer (Hyundai), and in your case you state the manual calls for 0w30, full stop. Other vehicle manuals call for a change in oil grade based on temperature, usually with a large overlap. This doesn't seem to be the case for your vehicle.

If you want some peace of mind, run a good quality 0w30 for a short interval (5000 miles as a bit of an arbitrary number) once you're back in Arizona, then have an oil analysis done. When you get the results back and they show nothing of concern, you can rest comfortably.
Thank you very much for that.
They include free oil changes for 3/36. Since their schedule is 8K, thats four oil changes. I've handled this car the way I handle every new vehicle. I paid for an oil change at 1000 miles then again at around 4,000 mi. They covered the 8, 16, and 24. I covered the 12, 20, and 28ish. I'm at 30K now and get the last freebie at 32K. All of which I bring them Mobil 1 0W30 ESP. Overkill I know but the car is had eight oil changes. Once I use up their last freebie, I'll resume my normal schedule of 5K..
At the rate I'm clocking the miles, I'll probably be back in Tucson just after my 32k oil change. I'll beat on that for 5K and send it out for analysis.
 

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All things considered - I'd stay with M1, but in 0W-40 flavor. It usually is easier to find than ESP 0W-30, and is cheaper too. At least around NC/SC border.
I'm just north of Dallas and get two 5-quart jugs (holds 6.5) of 0W30 at any local Walmart. The price remained stable for a long time at $24.97. Right now it's going for $29.97. I have not seen the 0W40 on any of their shelves honestly.
 
I'm just north of Dallas and get two 5-quart jugs (holds 6.5) of 0W30 at any local Walmart. The price remained stable for a long time at $24.97. Right now it's going for $29.97. I have not seen the 0W40 on any of their shelves honestly.
Not bad. None of my local 6 Wal-Mart Supercenters (got 20 in the area, not counting the smaller "Neighborhood" ones) carry M1 ESP 0W-30. They do have plenty of M1 AFE 0W-30 and M1 FS 0W-40 though.
 

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