M1 0w40FS vs 10w40HM

[Toy4x4]

Just changed the oil (M1 0w40FS) in the '07 4R V8, been using it for years with no issues whatsoever, always had great UOAs. So, of course, I start thinking about things AFTER its done. The truck is 18 years old, but only has ~86500 miles. It got me thinking about a comparable oil in the HM category. Would the M1 10w40HM be a better choice next time or keep with what has been working? Does the 0w40 have adequate ingredients to keep the seals and gaskets in shape vs the HM?

 

[Brian123]

What are your OCI's?

Can you post a Pic of the 1969 Chevelle?

 

[Overfill]

I see no advantage to the 10w-40 HM unless you are burning oil, and such advantage in that sense is less phos to the catalytic converter. If you aren't burning appreciable oil, then stay with 0w-40 FS

Does the 0w40 have adequate ingredients to keep the seals and gaskets in shape vs the HM?

yes, both are well equipped to keep the seals in appropriate shape.

 

[martinq]

I would consider the 10w40 HM for any of the following reasons:
- it's cheaper
- I don't need a 5w or 0w for my climate / application
- 18 years old would definitely fit "high mileage" to me
- the 10w40 has better specs / approvals

 

[Kalle.J]

I would consider the 10w40 HM for any of the following reasons:
- it's cheaper
- I don't need a 5w or 0w for my climate / application
- 18 years old would definitely fit "high mileage" to me
- the 10w40 has better specs / approvals

 

[BMWTurboDzl]

Just changed the oil (M1 0w40FS) in the '07 4R V8, been using it for years with no issues whatsoever, always had great UOAs. So, of course, I start thinking about things AFTER its done. The truck is 18 years old, but only has ~86500 miles. It got me thinking about a comparable oil in the HM category. Would the M1 10w40HM be a better choice next time or keep with what has been working? Does the 0w40 have adequate ingredients to keep the seals and gaskets in shape vs the HM?

Seals degrade over time due to heat/friction. As I understand it the tests for seal compatibility insure just that. Compatibility with seals rather than prolonging the life of seals. If you're burning oil (valve stem seals) or have a couple of oil leaks then a HM oil may reduce/eliminate that.

 

[Lawnman23]

Any leaky seals?

 

[Toy4x4]

What are your OCI's?

Can you post a Pic of the 1969 Chevelle?

It's not driven as much since I have the Mustang, but I do drive it weekly. Probably around 3k every two years, and that is the OCI.

It was not a real SS, but had a 396. Sold it in 2013:

 

[Toy4x4]

I would consider the 10w40 HM for any of the following reasons:
- it's cheaper
- I don't need a 5w or 0w for my climate / application
- 18 years old would definitely fit "high mileage" to me
- the 10w40 has better specs / approvals

Same price.
Not necessary...desert climate here in AZ. Can pretty much guarantee the truck never even seen 20*F.
18 yo, but very low miles for age.
The 10w "meets GF-6 standards". This is about the only info I could find and had to get it on Walmart's site as Mobil's site has no access to the PDS and SDS.

I did find this on Mobil's site, though: "It's true that most vehicles with more than 75,000 miles should be in excellent condition if Mobil 1 oils have been used regularly, and would not require some of the Mobil 1 Extended Performance High Mileage and Mobil 1 High Mileage benefits."

 

[Toy4x4]

Any leaky seals?

Nope. Not a drop on the driveway, nothing shows even a slight leak (that I can see and doesn't give off a smell like burning oil), and didn't add any on this past OCI.

 

[Lawnman23]

Nope. Not a drop on the driveway, nothing shows even a slight leak (that I can see and doesn't give off a smell like burning oil), and didn't ad any on this past OCI.

In that case, I would just keep on with the 0w-40. If it ain’t broke…

 

[edyvw]

I would consider the 10w40 HM for any of the following reasons:
- it's cheaper
- I don't need a 5w or 0w for my climate / application
- 18 years old would definitely fit "high mileage" to me
- the 10w40 has better specs / approvals

Like?

 

[Triple_Se7en]

Just changed the oil (M1 0w40FS) in the '07 4R V8, been using it for years with no issues whatsoever, always had great UOAs. So, of course, I start thinking about things AFTER its done. The truck is 18 years old, but only has ~86500 miles. It got me thinking about a comparable oil in the HM category. Would the M1 10w40HM be a better choice next time or keep with what has been working? Does the 0w40 have adequate ingredients to keep the seals and gaskets in shape vs the HM?

Your engine at 85k or 185k may not need HM oils, unless you are seeing symptoms it does. I keep HM oils on store shelves and shake my head every time I read about a member here that's using it inside a new (or almost new) vehicle.

Don't mess with your seals, until the time calls for it. I've driven numerous vehicles to junkyards 20 years and 300k after I bought them, that had no need for HM oils. Engines were all in great shape, except for dangerous rust underneath these vehicles.
\
Ever stop to think why brand new vehicles from Ford, GM or Stellantis don't leave the factory assembly line with HM oils in them? Leave your new / almost new seals alone. Buy medicines for your engine when they need them.

(Example) Don't be the person who prescribes himself antibiotics 24/7/365 to do infections maintenance therapy before the infection arrives. Goes the same with your expensive vehicles.

 

[Toy4x4]

Your engine at 85k or 185k may not need HM oils, unless you are seeing symptoms it does. I keep HM oils on store shelves and shake my head every time I read about a member here that's using it inside a new (or almost new) vehicle.

Don't mess with your seals, until the time calls for it. I've driven numerous vehicles to junkyards 20 years and 300k after I bought them, that had no need for HM oils. Engines were all in great shape, except for dangerous rust underneath these vehicles.
\
Ever stop to think why brand new vehicles from Ford, GM or Stellantis don't leave the factory assembly line with HM oils in them? Leave your new / almost new seals alone. Buy medicines for your engine when they need them.

(Example) Don't be the person who prescribes himself antibiotics 24/7/365 to do infections maintenance therapy before the infection arrives. Goes the same with your expensive vehicles.

I see your points. It just got me thinking, and I was bored, because the truck is 18 years old and the climate is VERY hot. Seals and bushing deteriorate more quickly. Summer temps 110*F+ and the roads 160-170*F. Mileage wise...good. It is just the age and extreme temps that got me thinking about it. I was looking at it as a low dose aspirin, heart help thing rather than an array of heavy duty meds. A minimum boost to help the aging seals to possibly ward off something in the future.
Seems like the 0w40FS has ingredients to help seals out, too, so I guess I'm alright.

 

[Patman]

\
Ever stop to think why brand new vehicles from Ford, GM or Stellantis don't leave the factory assembly line with HM oils in them?

Nobody but you ever stops to think about that

They don’t come from the factory with Amsoil or HPL either but that doesn’t mean that those aren’t better oils. Your analogy here simply doesn’t work.

 

[martinq]

I see your points. It just got me thinking, and I was bored, because the truck is 18 years old and the climate is VERY hot. Seals and bushing deteriorate more quickly. Summer temps 110*F+ and the roads 160-170*F. Mileage wise...good. It is just the age and extreme temps that got me thinking about it. I was looking at it as a low dose aspirin, heart help thing rather than an array of heavy duty meds. A minimum boost to help the aging seals to possibly ward off something in the future.
Seems like the 0w40FS has ingredients to help seals out, too, so I guess I'm alright.

Your ambient conditions answers my question, go for 10w40, it will have a HTHS viscosity. The HM is neither here nor there but I'd take it at that age. If I was in TX I'd be running a quality 15w40 year round.

 

[edyvw]

Your ambient conditions answers my question, go for 10w40, it will have a HTHS viscosity. The HM is neither here nor there but I'd take it at that age. If I was in TX I'd be running a quality 15w40 year round.

So, other oils don’t have HTHS viscosity?
And what ambient temperature has to do with choice between these two oils?

 

[martinq]

So, other oils don’t have HTHS viscosity?
And what ambient temperature has to do with choice between these two oils?

If you look at the HTHS of oils you'll find that 0w40 will usually be the lowest and 15w40 would be the highest (in a single product line).

If you don't need a 0w oil I would not run it. 15w40 should be good to use down to freezing otherwise I'd look at 10w or 5w as temperatures drop.

 

[kschachn]

If you look at the HTHS of oils you'll find that 0w40 will usually be the lowest and 15w40 would be the highest (in a single product line).

If you don't need a 0w oil I would not run it. 15w40 should be good to use down to freezing otherwise I'd look at 10w or 5w as temperatures drop.

I suppose if that is your only consideration or perhaps a high concern for cost. But a Euro 0W-40 has other attributes that would be superior such as demonstrated oxidation and sludge resistance as well as proven resistance to ring deposits and everything else the approvals bring you. Due to the requirements of a 0W winter rating the oil would also have better base stock.

The Euro 0W-40 is going to be a superior oil on nearly every aspect of performance.

 

[edyvw]

If you look at the HTHS of oils you'll find that 0w40 will usually be the lowest and 15w40 would be the highest (in a single product line).

If you don't need a 0w oil I would not run it. 15w40 should be good to use down to freezing otherwise I'd look at 10w or 5w as temperatures drop.

That absolutely doesn’t make any sense. That is ONLY true if both oils have base stocks, polymers, and additives of the same quality. For example, comparing Motul 300V 0W40 and 10W40. HTHS wise, just because oil has high KV100, does not mean it has high HTHS.10W40 HM is not even close in quality to 0W40. 0W40 FS is the entry track oil for Mobil1. I ran that oil at 300f on track at a 5,100ft altitude at 102f (running an engine at 5,100ft is more challenging than any heat in TX) and still did 5k OCI. He will never see that temperature, and as someone who spent A LOT of time on track, I would not put 10W40 HM in my engine even if someone paid me. But I will 0W40 FS, even if I have to pay.
You claim 10W40 has better approvals? Which ones? You obviously don't understand the approval process and which approvals are benchmark. 10W40 does not have MB229.5 (gold standard) Porsche A40 (that has track testing) or BMW LL01 (toughest oxidation standard).