What if "low tension ring" theory is all wrong?

[Faawrenchbndr]

Coolant temperature is used to determine operating temperature. That is what most car engine's computer use to determine engine temperature. 190 degrees is a general estimate for many.
Most cars don't even have an oil temperature sensor.

Pretty much all cars made in the last few years having an oil temperature sensor. You may not have a gauge, but you do have an oil temperature sensor.

 

[OVERKILL]

Agreed, there are many, many factors. Wanted to point out that today’s low tension is not yesterday’s. And the piston in today’s minivan or grocery getter sedan looks like the piston in a 13k redline 1995 superbike. Sometimes a more radical design in fact.

A lot has changed.

Yeah, the GDI/TGDI pistons can look pretty wild. The HEMI pistons don't look too exotic. Short skirts, like we saw on the early LSx engines in the 1990's:

Neither do the Pentastar ones (which is a minivan engine):

Of course both of these are naturally aspirated port-injected engines. So, while modern, with low tension rings (context of this discussion) they are more "traditional".

BMW B58 pistons in comparison:

Edit to add:
"Low tension" isn't a fixed target and I'm not sure ascribing it to a timeline, like 2003 vs 2023 not being the same is necessarily valid either. The idea of using rings with less tension, to reduce frictional losses, achieved by making them thinner and exerting less outward pressure I'm sure we can agree is a decades-old concept. That concept itself hasn't changed. What has changed is the implementation, and that in turn is relative to what they are fitted to. So it's not that low tension rings themselves, at least conceptionally, have necessarily evolved/changed considerably over this timeframe, but rather that the applications to which they are fitted have. A 2003 HEMI isn't going to have much in the way of changes, if any, regarding ring spec from a 2026 HEMI, because this is a decades old engine architecture that's still port-injected and naturally aspirated. On the other hand, the 1.5L TGDI Honda is likely going to have some significant design advancements in terms of piston design, perhaps coatings, ring layout and design decisions around stack height, fitment...etc because it's a cutting-edge TGDI mill designed to be extremely low friction and high efficiency.

So, my opinion is that the distance between "yesterday's" and "today's" low tension rings is itself a variable, one that depends on your reference points. A 2026 HEMI is likely closer to what we saw in the 1990's LS1 than it is to what we find in the Earth Dreams 1.5L. This puts us back at my point about the myriad factors influencing the end result and the stack of design decisions that ultimately culminate in what we experience in terms of reliability, durability, oil consumption, abuse tolerance...etc.

 

[Hohn]

There is no ill will. Coolant temperature is just that, coolant temperature.
Oil temperature can fluctuate a lot. It is in most cases, 30-40f higher then coolant in normal driving conditions. For example, my Sienna with 2GR-FE had coolant temperature stuck at 190f. Oil temperature on other hand was 225-230f during normal hwy speeds. It would regularly jump to 250f over mountain passes while coolant temperature stayed same (5f +-).

BMW went away with coolant gauge precisely bcs. they are irrelevant. They installed in most models oil temperature gauge because that is what resembles true engine temperature. For example, on track, before installing oil cooler, coolant temperature in my BMW would run at 178f (water pump goes into high effectiveness mode). However, DME at the same time was cutting power bcs. my oil temperature was 302f!

Thank you for highlighting this. I think a lot of people don’t realize that the oil carries about 20% of the total heat rejection that isn’t to the exhaust pipe. Coolant is thermostatically controlled and has a lot of excess capacity under many conditions.

Oil being unregulated is highly variable.

I’m no fan of BMW these days, but their logic behind trading coolant temp for oil temp is quite solid, IMHO. I’d happily trade my useless coolant temp info for oil temp that actually means something.

 

[edyvw]

Thank you for highlighting this. I think a lot of people don’t realize that the oil carries about 20% of the total heat rejection that isn’t to the exhaust pipe. Coolant is thermostatically controlled and has a lot of excess capacity under many conditions.

Oil being unregulated is highly variable.

I’m no fan of BMW these days, but their logic behind trading coolant temp for oil temp is quite solid, IMHO. I’d happily trade my useless coolant temp info for oil temp that actually means something.

Not to mention warming up engine. Coolant temperature is up while oil temperature is way down. People pushing cars thinking that they warmed up engine.

 

[TacoFergie]

I skimmed through this thread in about 45 minutes so I’m sure I am missing some valuable intel. But based off what I’ve read, thicker seems to be better in general with no real ill effects? Am I understanding that correctly?

For example. My 21 Subaru Ascent with the FA24DIT specs 0w20. But a 0w30 or 5w30 would be better under this assumption, possibly even a 0w40? It’s a wife driven car that sees remote starts, sometimes extended idle, 15-20min drives to/from work, city driving for errands as well as random road trips. Luckily it doesn’t have start/stop features!

I have used Mobil 1 ESP 0w30 and AFE in the past due to oil shearing (per Blackstone) which ended up actually being due to really high fuel dilution over 5% (OAI) over 4k-5k OCI’s which is common for this engine. Results looked good despite fuel dilution. I haven’t done another UOA in around 40k (76k total on the clock) and have used primarily Castrol EDGE Extended Performance at 4k OCI’s since I got a bunch super cheap. Now I’m out of it and recently changed it to Valvoline Restore and Protect 0w20. For reference I do live in NW IA where we seen -15F to 100F+. It has zero issues, doesn’t use oil and when I recently did the plugs they looked great. I use Techron prior to each oil change and it runs 91 for every fill up, not top tier since the few stations we have are out of our way.

 

[edyvw]

I skimmed through this thread in about 45 minutes so I’m sure I am missing some valuable intel. But based off what I’ve read, thicker seems to be better in general with no real ill effects? Am I understanding that correctly?

For example. My 21 Subaru Ascent with the FA24DIT specs 0w20. But a 0w30 or 5w30 would be better under this assumption, possibly even a 0w40? It’s a wife driven car that sees remote starts, sometimes extended idle, 15-20min drives to/from work, city driving for errands as well as random road trips. Luckily it doesn’t have start/stop features!

I have used Mobil 1 ESP 0w30 and AFE in the past due to oil shearing (per Blackstone) which ended up actually being due to really high fuel dilution over 5% (OAI) over 4k-5k OCI’s which is common for this engine. Results looked good despite fuel dilution. I haven’t done another UOA in around 40k (76k total on the clock) and have used primarily Castrol EDGE Extended Performance at 4k OCI’s since I got a bunch super cheap. Now I’m out of it and recently changed it to Valvoline Restore and Protect 0w20. For reference I do live in NW IA where we seen -15F to 100F+. It has zero issues, doesn’t use oil and when I recently did the plugs they looked great. I use Techron prior to each oil change and it runs 91 for every fill up, not top tier since the few stations we have are out of our way.

Thicker oil won’t have ill effects per se. Nothing bad will happen.
But, let’s say ESP 0W30 compared to CRP 0W20.
ESP has minimum HTHS of 3.5cP. It has better protection margin. HTHS is key to lower wear. But, higher dynamic viscosity means more resistance. You might notice or not, but turbo will spool slower over 0W20. It will use more gas (probably can’t notice that) and will create bit more heat.
IMO, turbo engine, European A3 or C3 (ESP 0W30) approvals only.

 

[Mechanician]

Pretty much all cars made in the last few years having an oil temperature sensor. You may not have a gauge, but you do have an oil temperature sensor.

I don't believe you are correct. I know that some manufactures have been using them lately, but nowhere near pretty much all.
Going to OEM part sites I can't find one for a late model common Honda. I also checked 2024 VW Jetta - not listed.

 

[Mechanician]

There is no ill will. Coolant temperature is just that, coolant temperature.
Oil temperature can fluctuate a lot. It is in most cases, 30-40f higher then coolant in normal driving conditions. For example, my Sienna with 2GR-FE had coolant temperature stuck at 190f. Oil temperature on other hand was 225-230f during normal hwy speeds. It would regularly jump to 250f over mountain passes while coolant temperature stayed same (5f +-).

BMW went away with coolant gauge precisely bcs. they are irrelevant. They installed in most models oil temperature gauge because that is what resembles true engine temperature. For example, on track, before installing oil cooler, coolant temperature in my BMW would run at 178f (water pump goes into high effectiveness mode). However, DME at the same time was cutting power bcs. my oil temperature was 302f!

What is your answer to the question of what operating temperature is then?
Is it not possible to tell without an oil temperature gauge?
Would that temperature be the same on an engine with a non-temperature regulated oil cooler, as one without an oil cooler?

 

[CR94]

In the Bulletin Honda released for stuck rings, these reasons are listed on page one. No mention of oil quality, or OCI.
https://static.nhtsa.gov/odi/tsbs/2015/SB-10100797-9340.pdf

POSSIBLE CAUSES
Under certain specific circumstances the engine may create deposits on the oil control rings, which may lead to
increased oil consumption when all of the following conditions occur simultaneously on a regular and prolonged basis:
• The engine is cold (not warmed up to operating temperature)
• Hard acceleration while the engine is cold
...

Good point, too often overlooked.
In my Prius, Toyota tries to save the engine from that form of abuse by relying primarily on the battery for moderate acceleration during the first one minute after cold starts (which can't be great for the battery, but that's another topic). However, if you press the accelerator farther to demand more power than the battery should provide, it takes that power from the still-cold engine, after all. I try not to do that, and haven't had trouble with excessive oil consumption, as a lot of owners of the same model have at similar mileage---coincidentally or not.

 

[edyvw]

What is your answer to the question of what operating temperature is then?
Is it not possible to tell without an oil temperature gauge?
Would that temperature be the same on an engine with a non-temperature regulated oil cooler, as one without an oil cooler?

Engine Operating temperature is always oil temperature.
What cooler has to do with it? Which one? Fluid to fluid “cooler,” which really serves to accelerate oil temperature raise, or real radiator oil cooler? Puck or heat exchanger is primarily accelerant.
Radiator oil cooler, factory set up will have thermostat. For example on my BMW it is OE cooler from 335 and has factory oil thermostat at 110c. Coolant temperature in my BMW will reach its temperature in few minutes. Super fast. Oil, or engine operating temperature takes 8-10mls.
Almost all modern vehicles will have puck in oil filter assembly or coolant lines will pass through oil gilter housing assembly. Still, as I mentioned about Sienna or this BMW i have, discrepancy between coolant and oil can be really big.

 

[TacoFergie]

Thicker oil won’t have ill effects per se. Nothing bad will happen.
But, let’s say Mobil 1 ESP 0W30 compared to CRP 0W20.
Mobil 1 ESP has minimum HTHS of 3.5cP. It has better protection margin. HTHS is key to lower wear. But, higher dynamic viscosity means more resistance. You might notice or not, but turbo will spool slower over 0W20. It will use more gas (probably can’t notice that) and will create bit more heat.
IMO, turbo engine, European A3 or C3 (Mobil 1 ESP 0W30) approvals only.

Thank you! I’ll probably run Valvoline Restore and Protect for a few more oil changes. I’m considering stepping up to 5w30 since it appears that there should be no issues even in my climate if I am understanding that correctly? I don’t think I have extensive buildup based off no oil consumption as well as the quality oils and intervals I have been doing, but the inevitable fuel dilution is probably contributing to the potential for build up. Then again, like many things, I tend to overthink it instead of keeping it simple. Though it would be nice to just buy one oil at a single oil weight for all 4 of my vehicles.

 

[ChemLabNL]

Thank you! I’ll probably run Valvoline Restore and Protect for a few more oil changes. I’m considering stepping up to 5w30 since it appears that there should be no issues even in my climate if I am understanding that correctly? I don’t think I have extensive buildup based off no oil consumption as well as the quality oils and intervals I have been doing, but the inevitable fuel dilution is probably contributing to the potential for build up. Then again, like many things, I tend to overthink it instead of keeping it simple. Though it would be nice to just buy one oil at a single oil weight for all 4 of my vehicles.

Go back to Mobil 1 ESP 0w30. Shear stable/low NOACK 0w30. 229.52/C30/504/507. Mobil 1 ESP 0w30 is ideal.

 

[facility1]

Go back to ESP 0w30. Shear stable/low NOACK 0w30. 229.52/C30/504/507. ESP 0w30 is ideal.

Yup Mobil 1 ESP will save the day.

 

[Mechanician]

Engine Operating temperature is always oil temperature.
What cooler has to do with it? Which one? Fluid to fluid “cooler,” which really serves to accelerate oil temperature raise, or real radiator oil cooler? Puck or heat exchanger is primarily accelerant.
Radiator oil cooler, factory set up will have thermostat. For example on my BMW it is OE cooler from 335 and has factory oil thermostat at 110c. Coolant temperature in my BMW will reach its temperature in few minutes. Super fast. Oil, or engine operating temperature takes 8-10mls.
Almost all modern vehicles will have puck in oil filter assembly or coolant lines will pass through oil gilter housing assembly. Still, as I mentioned about Sienna or this BMW i have, discrepancy between coolant and oil can be really big.

It's true that that oil temperature, unlike coolant temperature, fluctuates quite a bit under different driving conditions.
An oil cooler, it's size and type, or the lack thereof, has to have something to do with oil temperature. I think it's impossible to make general statements that are accurate in all instances.

Added oil coolers can also be placed externally by the radiator on water cooled engines, or over the air intake on air cooled engines.
Most oil coolers on average vehicles, are temperature regulated, like the rest of the engine, by the cooling system's thermostat. Those do have the benefit of helping warm cold oil faster as well.
Many engines operate fine, and live a long life, with no oil cooler at all.

At what oil temperature, can a driver can consider their engine to be at operating temperature?

 

[ChrisD46]

End result for me with Hyundai / Kia vehicles is to either stay with Valvoline Restore and Protect 5W30 after 4 OCI’s are completed or go back to Mobil 1 ESP 0w30?

 

[ChemLabNL]

API ILSAC Dexos1 specs are a joke. Just find the cheapest 229.5/C30 oil and you will always be better off

 

[Patman]

At what oil temperature, can a driver can consider their engine to be at operating temperature?

IMO when the oil temperature reaches 180F it’s good enough to start driving it harder. All 4 of my Corvettes that I’ve owned have had oil temperature readouts and I will usually wait until 180F before going full throttle (although the odd time I might do it at 160)

 

[Faawrenchbndr]

I don't believe you are correct. I know that some manufactures have been using them lately, but nowhere near pretty much all.
Going to OEM part sites I can't find one for a late model common Honda. I also checked 2024 VW Jetta - not listed.

I guess we’ll agree to disagree

 

[edyvw]

It's true that that oil temperature, unlike coolant temperature, fluctuates quite a bit under different driving conditions.
An oil cooler, it's size and type, or the lack thereof, has to have something to do with oil temperature. I think it's impossible to make general statements that are accurate in all instances.

Added oil coolers can also be placed externally by the radiator on water cooled engines, or over the air intake on air cooled engines.
Most oil coolers on average vehicles, are temperature regulated, like the rest of the engine, by the cooling system's thermostat. Those do have the benefit of helping warm cold oil faster as well.
Many engines operate fine, and live a long life, with no oil cooler at all.

At what oil temperature, can a driver can consider their engine to be at operating temperature?

In ALL instances oil will warm up much slower than coolant. Unless engine has heat exchanger of similar size as an IDK, radiator, which they don’t, oil always warms up slower.
Almost all, if not all new vehicles have some type of heat exchanger as that is easy way to address emission requirements. Older? No, not all definitely.
Some manufacturers indicate in manual when oil temperature is appropriate, but if memory serves me right Ferrari had in some manual 165f. I personally wait 180-190f.

 

[edyvw]

Thank you! I’ll probably run Valvoline Restore and Protect for a few more oil changes. I’m considering stepping up to 5w30 since it appears that there should be no issues even in my climate if I am understanding that correctly? I don’t think I have extensive buildup based off no oil consumption as well as the quality oils and intervals I have been doing, but the inevitable fuel dilution is probably contributing to the potential for build up. Then again, like many things, I tend to overthink it instead of keeping it simple. Though it would be nice to just buy one oil at a single oil weight for all 4 of my vehicles.

No issues whatsoever running 5W30 where you live.
Euro oils have more stringent limits on deposits etc. Mobil 1 ESP also has esters (0W30) so it will run cleaner, preventing potential deposits problems.