Normal. Saw on another thread that synthetic oil is safe up to 275F

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I'm running an ej257 but I used to run hot while working in SoCal until I upgraded to a koyorad. What you should be concerned with is knock. I'm not sure how the new blocks are or if they have the cylinder 4 temperature problem, but I did the GADT cylinder 4 cooling mod and bypassed the throttle body coolant. If you only visit places that see sub freezing temperatures consider bypassing your throttle body. The southwest heat is no joke!

 

XT here and saw my temperature go up to 225f in this heat going up a long hill.

 

The Subaru owner's manual on page 522 says:

Oils of lower viscosity provide better fuel economy. However in hot weather, oil of higher viscosity is required to properly lubricate the engine.

Then it has a diagram showing 0w-20 up to 100 degrees F

If I were routinely seeing prolonged oil temps above 220 in the summer then I would consider a 0w-30 or 5w-30 oil, which is only slightly thicker than 0w-20 or 5w-20 especially if you have a turbo.

 

There is really two separate questions to be asked here.

1. What oil temp is considered above normal operating temps by Subaru? This may be something they release but chances are they don't offer it up to the public.

This has very little to do with actual temperature and more about oil pressure as they have a close relationship. At a certain point too high of a temp will lead to too low of a pressure. This isn't due so much to the oil itself but the spec of the oil pump and engine specs. The relationship between oil temp and pressure is different in different engines.

This would help you determine if your temps were too high.

*spoiler alert 223F would not even be close

2. At what temp does it become too hot for the oil itself to where it starts prematurely breaking down. Most recent research and statements from oil manufacturers seem to suggest that a full syn can handle close to 400F without loosing its ability to lubricate and hold viscocity.

As an anecdote my track car ran 5w30 with over 1000km of on track WOT driving which had the oil see temps of 298F. At the time I still daily drove it and I did an oil analysis after 11,000km and blackstone labs showed it could have run longer. Viscocity was still well within spec.

With a higher viscocity your oil temps will also be higher. I now run 0w20 in that same track car and with all things equal I would see 8-10F lower temps with 0w20.

IMO you are fine with those temps and your oil. You are over thinking it based on old info from back in the day when oil was half of what it is now.

 

On modern cars (especially direct injected motors) you want oil temp to reach at least 212F at some point during your drive in order to drive off water vapor that inevitably builds in the motor. Similarly if oil doesn't reach high temps you can't drive off gas vapors that are also common in the oil for direct injected motors. This is all correlated to gas smell in oil on very short trips since the oil can't reach temp to evaporate water/gas vapors. That was the issue for example on the late model Honda CRVs for people that drove short distances, gas vapors could not be evaporated by the oil for short trips since oil can't reach 212F, this is of course compounded by the fact the Honda CRV has a tiny 1.6 liter motor, the turbo also exacerbates the oil/gas dilution which again should not be an issue if the car is driven a distance long enough for the oil to reach 212F.

Now, some trips on the Subaru I see 205 degF but I bet the sensor location doesn't represent the hottest path of the oil in the motor. My commute is long enough that I reach at least 205 degF which makes me at least guess that somewhere in the oil pathway there is 212 degF.

I meticulously keep track of my oil temp in my 2020 outback 2.5i and up 20 mile highway hills here at 75 mph I see 225 degF or so which is no issue for modern synthetic oils. When I tow, I see no more than 235-240 degF, which again is peanuts for any modern synthetic oil.

Its fun to google images of any BMW oil temp gauge which has its "middle" at 250 degF. Max on the BMW oil temp gauge is 360 degF. Just as a reference see link below.

I have always theorized the front active grill shutters that the Subaru has are there to do exactly that -- ensure the motor and by definition motor oil gets hot even for short trips, otherwise you would risk gas/water vapor not being removed from the oil.

Is this normal ? Oil temp related

 

On modern cars (especially direct injected motors) you want oil temp to reach at least 212F at some point during your drive in order to drive off water vapor that inevitably builds in the motor. Similarly if oil doesn't reach high temps you can't drive off gas vapors that are also common in the oil for direct injected motors. This is all correlated to gas smell in oil on very short trips since the oil can't reach temp to evaporate water/gas vapors. That was the issue for example on the late model Honda CRVs for people that drove short distances, gas vapors could not be evaporated by the oil for short trips since oil can't reach 212F, this is of course compounded by the fact the Honda CRV has a tiny 1.6 liter motor, the turbo also exacerbates the oil/gas dilution which again should not be an issue if the car is driven a distance long enough for the oil to reach 212F.

Now, some trips on the Subaru I see 205 degF but I bet the sensor location doesn't represent the hottest path of the oil in the motor. My commute is long enough that I reach at least 205 degF which makes me at least guess that somewhere in the oil pathway there is 212 degF.

I meticulously keep track of my oil temp in my 2020 outback 2.5i and up 20 mile highway hills here at 75 mph I see 225 degF or so which is no issue for modern synthetic oils. When I tow, I see no more than 235-240 degF, which again is peanuts for any modern synthetic oil.

Its fun to google images of any BMW oil temp gauge which has its "middle" at 250 degF. Max on the BMW oil temp gauge is 360 degF. Just as a reference see link below.

I have always theorized the front active grill shutters that the Subaru has are there to do exactly that -- ensure the motor and by definition motor oil gets hot even for short trips, otherwise you would risk gas/water vapor not being removed from the oil.

Is this normal ? Oil temp related

This couldn't be more true. On my 2015 legacy with the 2.5 and 180k miles, I would normally get 220s just on my highway commute. With the outback xt I would see around 200 on that same commute. When towing a 5x8 trailer 800 miles, highest I saw was 236 in the hills of PA. I'd say the cooling in this car works extremely well, almost too well

 

I would imagine, considering the bmw gauge comment, that the subie gauge would still be inside the “white” area. I rarely see 212 during my drives, though comes close most often for traffic.

 

Mine was at 226 the other day. It’s normally around 220 lately.

 

Thank you all for your comments. I’m feeling a lot more confident now.😁

 

I rarely see much over 230 on the highway, but that is in the winter and is a frequent occurrence. I’m sure at low speeds in the summer it will get much hotter (less air flow across the oil cooler).

 

Thats exactly how they design the current thermal management system for modern direct injected motors.

If you look, during the winter the active shutters in the front grill are rarely open (during winters, only during mild days do I see these open). In addition to the coolant thermostat, my guess is that most auto makers add active shutters do get even finer control on the temperature of the motor and by definition the oil temperature by controlling the airflow through the front gill. It is critical with these direct injected motors for vapor mitigation as well as to control carbon build up especially during the winter when getting the oil to proper temperature requires these shutters to be closed.

Anyway, 230 on the highway is totally within expectation depending of course on grade and speed.

 

I sometimes I see 220 to 225°F. Last summer the outside temp was 118°F and after leaving the freeway and driving on city streets the oil temp gauge was still displaying over 220°F.

Recently, I washed the car starting at 6 am then left it sitting until 5pm (11 hours) when we took off. A t ½ block out I noticed the oil temp was at 91°F and the outside temp was showing 80°F. A dark hood setting in the sun obviously heats the engine and its oil.

In the1970s there was a comprehensive report based mostly on Mobil 1, an ester, which had data that showed the oil could withstand more than 400°F. However, theoretically there can be localized pressure areas, including micro-points on new engines with fewer miles, that can have higher surface temperatures than measured in the bulk of the oil.

 

This is likely a dunb question but where are you all finding oil temp? I knew how to see it on my 2016 but cannot find it in the menu on my 2021 Onyx.

 

Page 208 of the manual discusses the favorite things to display on the CID.

 

I like beating dead horses and my bias is old-school based on other Turbo engines I have owned and the constant worry about turbos and oil. Yes this is about me and my obsession, not about what anyone else should do with their cars.

Subaru used to specify higher viscosity and shorter change intervals for their turbo motors vs naturally aspirated. It made sense. Now they specify the same viscosity and intervals for naturally aspirated and turbo, so it gives me pause.

The WRX/STI EJ guys almost all ran 5w-40 oil in an attempt to prevent dreaded spun bearings when the lubrication film between the crank and the main bearings fail. The specification there is HTHS or High Temperature High Shear, which isn't identical to viscosity but it is related. Many ran Rotella T6 5-40 with robust extreme pressure additives. I did.

An ounce of prevention is worth a pound of cure so I go overboard out of paranoia.

For the first time in my life, I actually did a blackstone oil analysis (GF-5 SN-Plus D1G2) and in 2845 miles my oil dropped a grade from 30 to 20. My worry isn't so much that a 20 weight oil is too thin, but if it dips to 16 grade. So I put in a resource conserving xw-30 oil and end up with 20, which is OK.

Used Oil Analysis (UOA) Reports for Gen 6 OB

Let's get this party started! Please post the following : Vehicle - Model year, engine, etc Miles on vehicle/engine Miles on oil change interval Motor oil used Oil filter used Attachment of UOA report or text copied & pasted Dialogue is welcome but let's focus on compiling UOA data first and...

www.subaruoutback.org

So my issue isn't with 20 weight oil being put in the engine, it's the uncertainty of whether it's still 20 weight in the middle of your change interval, particularly if you're towing or in hot weather. For me I'm in perpetual summer, and frequent short trip driving puts me in severe service.

Then again the Ascent folks with the same motor stick to 0w-20 religiously and tow up to 5000 pounds in the summer and have never had an oil related issue - so I admit that I'm overthinking this and it's my issue, not a Subaru issue.

 

@SilverOnyx your report on the oil grade dropping reminds me of my own research using Valvoline’s lab in California many years ago. The conclusion then was that some oils drop viscosity over time while others don’t depending on the particular formulation used by the oil manufacturer. So a different brand from what you’re using now could be better, could be worse.

This might also explain the oil consumption I’ve been seeing, as it’s not uniform but starts somewhere in the 3-4K mile point after a change. Thus my viscosity could be dropping just enough to allow some burn off. It’s something I’ll continue to track closely but I’m beginning to be less concerned about it than I was before. Why a Subaru can’t go as long between changes without using oil as a Honda is still a mystery I’ve yet to solve.

 

If more people submitted blackstone oil analysis to that other thread we'd be getting somewhere.

 

You know a couple in there are mine off a new car and 3K intervals (decided my outback was a prima donna)... and while some of the factory fill stuff and initial metals are washing out and whatnot, TBN is good, no insolubles, etc, the one thing that really had my head scratching is that at 3K miles, the Subaru 0W20 is at the lower end of/about to drop out of spec. Maybe its been that way for the full 3K, but I doubt it.

 

I was traumatized when my first 2020 Outback Onyx XT dropped 2 cylinders the first week I had it. It was towed to the dealership and they gave me a different 2020 Onyx XT. After that episode I have been obsessing, so again it's me. After they gave me the new car, they said "oh it was just a loose connector" yet it took them about a month to get me the new car. If it was a loose connector then why didn't they give me back the original car after putting the wire back?

As I've mentioned before I have trust issues and a salesman telling me something was a loose wire doesn't make me believe it. But I do not think it was an oil related failure, so perhaps my obsessing is misplaced. Still, it has me on guard overall. So this explains why I'm going overboard and over thinking this stuff.

My logical mind tells me that 0w-20 is fine if you use severe service intervals. Another factor is that in my area (Hawaii) believe it or not, we are not part of Subaru of America, so SOA will do nothing for me if I have issues with my dealer. My dealer isn't awful but there is no backup higher power to appeal to.

 

WOW! You do have a unique situation. I hope this one works out for you.

 

Just to add, after the issue with my first Onyx, I contacted SOA to try to buy the extended warranty for peace of mind for the second one. They told me they cannot sell it to me because my car does not fall under SOA.

 

That sure does not seem right. That would upset me also.

 

How can Hawaii not be SOA?

 

And just as important - if it isn't considered SOA then why does it not fall under another umbrella corporation that a customer in Hawaii can appeal to?

That would concern me as it really leaves the dealer as the only customer service outlet for the customer.

 

Try entering a Hawaii zip code, like 96801

Subaru Cars, Sedans, SUVs | Subaru of America

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www.subaru.com

 

So its, um SOH? That just feels wrong

 

Reviving this old thread - my oil temps are hotter than before, at 11k miles now, during engine braking down the mountain I saw 220F - not a dangerous temp by any means but I never see that temp when going up the other way. The difference is that during engine braking my RPM is 4000 and going up hill it's only around 2k but surely using more fuel - under engine braking I presume all fuel is shut off so this seems odd to me. Yes the friction is higher but with less combustion I would think it would be cooler. Curious. At cruise it's 205 at 70 mph.

 

Interesting. Quick google search on the topic yields opposing opinions:

This site says engine breaking is ok:

What is Engine Braking (and Why you Should do it)

Using your engine to help you slow down is not only better for your brakes, it's better for your wallet. Find out why.

www.matfoundrygroup.com

This guy says it's bad:

The Dangers of Engine Braking: Why it's Bad for Your Car

Discover why engine braking is bad for your engine. When you take your foot off the gas, the pistons pull oil back into the cylinder.

ricksfreeautorepairadvice.com

Either way, I'm not sure how the higher rev with no combustion going on could increase your temps. That's definitely a question for an engineer!

This link mentions this:

Engine Braking 101: A How-To Guide, Benefits, & FAQs

Engine braking can provide incredible benefits when done correctly, such as reduced brake wear and fuel economy. Read on to learn more.

www.repairsmith.com

A. High Engine RPM

When you downshift for better engine braking, your engine’s RPM (revolutions per minute) could shoot up. And driving your vehicle at a high RPM for long durations can cause the engine to overheat, placing heavy demands on your cooling system and radiator.
However, as long as your RPM stays well under the redline, your engine shouldn’t experience any problems.

 

Thanks I just read all of the articles and I don't think any of them are wrong. I've been doing a lot of engine braking on all of my manual transmission cars and it never caused any issues that I am aware of, but it's true that it's putting vacuum in the cylinders. I've also seen resources that recommend engine braking (vacuum pulls) especially during engine break-in to purposely draw oil into the rings to keep them free and remove fine particles from the piston rings wearing into the bore.

Complete Engine Break In Procedure | MAPerformance

Our complete engine break in procedure checklist will have you doing it right the first time every time! Read below to learn more.

www.maperformance.com

But after break-in, chronic engine braking could put more oil in the cylinders that eventually adds to deposits, especially if you have worn valve guides. But the pressure against piston rings during combustion is astronomically higher under acceleration than under engine braking, so unless piston rings act as a one-way valve, it would be hard to imagine that it allows that much stuff to get past the rings.