How to adapt oil characteristics choice with constant 250F operating temp

Tak

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Hello community,

So for emissions and efficiency, the BMW F90 M5 has an operating oil temperature of 120 degrees Celsius or approx 250 Fahrenheit. I'm guessing this is a new trend in the emission race and probably common among many new performance cars. The M5 even keeps cooling circulation suppressed (thermostat etc) till the operating temperature is reached, instead of initiating the cooling process at 90 degreesC for example.

So based on this new (to me) concept, should we be looking at new oil characteristics choice to ensure engine wear protection? With a vague understanding of manufacturer approvals A2, A3, B2, B3, LL01, LL04 of the recommended oils (0W-30, 5W-40), it seems that the HTHS requirement is equal or greater than 3.5 mPas. Is this enough?

I know that a M1 or Motul BMW Specific oil would be more than fine, but I'm curious to see if anybody in the community has come across any matters of concern with constantly running such high temps in performance cars and if you have any recommendations.
Thanks
Tak
 
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Oils are more alike than different these days because the ratings have become very demanding . Look at the data sheets.
 
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What oil rating does BMW recommend?
I have seen 0-30, 5-30, 0-40, 5-40 depending on location...
I have never seen BMW recommend a "rating", they require an approval and they recommend grades. But as is the case with most approvals the grade is nearly irrelevant except for minor quibbling over the winter rating. The approval is what matters.
 

Tak

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Thanks for the replies. BMW dealer here uses BMW approved eni i-sint with the LL01 approval. From what I understand, eni used to be Agip and was regarded a decent Italian oil. Should I go with that or should I be looking for something because of the seemingly demanding 250 degree running temps? Not much info on those oils here...
 

Tak

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I have never seen BMW recommend a "rating", they require an approval and they recommend grades. But as is the case with most approvals the grade is nearly irrelevant except for minor quibbling over the winter rating. The approval is what matters.
Apologies, I was under the impression the ll01 and ll04 are BMW ratings...
 
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Apologies, I was under the impression the ll01 and ll04 are BMW ratings...
Longlife-01 and Longlife-04 are BMW approvals which dictate nearly every aspect of the oil's characteristics and properties. One of the dictates is the HT/HS which defines what grades are available. Since HT/HS is a far better value to predict the performance of the oil, it is better to focus on approval rather than grade designation. Grade is irrelevant when HT/HS is specified except possibly for the winter rating, which in your case is also irrelevant.

And as to your other post about operating temperature, Longlife-01 and Longlife-04 approval have stringent oxidation and stay-in-grade requirements.
 
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So for emissions and efficiency, the BMW F90 M5 has an operating oil temperature of 120 degrees Celsius or approx 250 Fahrenheit. I'm guessing this is a new trend in the emission race and probably common among many new performance cars. The M5 even keeps cooling circulation suppressed (thermostat etc) till the operating temperature is reached, instead of initiating the cooling process at 90 degrees C for example.
I can't comment on the oil ratings question but I want to clarify something. Are you saying that the thermostat stays closed until the engine temperature reaches 120C? I'm thinking about oil temp vs engine temp. Thanks
 

Tak

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T
I can't comment on the oil ratings question but I want to clarify something. Are you saying that the thermostat stays closed until the engine temperature reaches 120C? I'm thinking about oil temp vs engine temp. Thanks
To be specific, the cooling system via the thermostat aims to heat up the oil as quickly as possible. I’ve seen full temp achieved in 5 minutes of city driving.

actual info:
F90 Complete Vehicle
4. Engine
4.9.3. Engine oil cooling
The S63T4 engine has an air-coolant heat exchanger for cooling the engine oil which is built-in flat in front of the cooling module. To make possible quick heating-up of the engine oil, a thermostat is integrated in the oil sump upper section. The thermostat releases the flow to the engine oil cooler at an engine oil temperature of 212°F and is fully open at an engine oil temperature of 293 °F.
S63B44T4 engine, engine oil cooling
Index Explanation
1 Thermostat
2 Upstream engine oil cooler

You can find this on page 63
 
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Thanks for the replies. BMW dealer here uses BMW approved eni i-sint with the LL01 approval. From what I understand, eni used to be Agip and was regarded a decent Italian oil. Should I go with that or should I be looking for something because of the seemingly demanding 250 degree running temps? Not much info on those oils here...


This is your answer. Look for that BMW LL01 approval.
 
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CleanSump

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And we thought lean-burn and 192F thermostats made cars run hot in the 1970s!
 

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T

To be specific, the cooling system via the thermostat aims to heat up the oil as quickly as possible. I’ve seen full temp achieved in 5 minutes of city driving.

actual info:
F90 Complete Vehicle
4. Engine
4.9.3. Engine oil cooling
The S63T4 engine has an air-coolant heat exchanger for cooling the engine oil which is built-in flat in front of the cooling module. To make possible quick heating-up of the engine oil, a thermostat is integrated in the oil sump upper section. The thermostat releases the flow to the engine oil cooler at an engine oil temperature of 212°F and is fully open at an engine oil temperature of 293 °F.
S63B44T4 engine, engine oil cooling
Index Explanation
1 Thermostat
2 Upstream engine oil cooler

You can find this on page 63

They are describing the coolant/oil heat exchanger, as well as the stand-alone oil cooler, which is perfectly normal. The coolant/oil heat exchanger serves two functions:
1. It brings the oil up to temp faster, allowing heat-activated additives to start working faster and reduce viscosity to improve efficiency
2. It keeps the oil temperature in check (oil cooler function) to prevent the oil from getting too hot.

My S62 had a thermostatically controlled heat exchanger in the valley and that engine was horrible for the oil not getting up to temperature in the winter months. They've added the coolant/oil heat exchanger to remedy that in later models.

The coolant/oil heat exchanger is very popular on trucks and high performance vehicles. My SRT has one, as does my RAM 1500. Most OEM's don't go to the lengths of having two separate oil coolers, but BMW isn't most manufacturers.
 
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It is an old thread, but these temperatures are nothing new in BMW. In S63 it is controlled via DME and thermostat opens and closes at direction of DME (ECU).
For hwy run DME will keep engine run as hot as possible. In the city it will lower temperature few degrees, on track it will run it around 80c.
DME in my engine uses electric water pump to do same. Hwy=113c. Track=85c, and other modes in between. In some it is possible to adjust operation by coding DME.
 
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