ANOTHER oil temp thread
 

Hi everyone,

I've looked up the forum regarding the oil temperature. I'm on 0W20(full synthetic), and occasionally do spirited driving in the mountains. Bone stock.

I usually drive until I reach 115C, roughly 240F, and then slow down the pace to cool down (by easing off the throttle, upshifting and etc.), and then drive hard again. Last weekend, I peaked at 118C once, 244F, and then slowed down right away. As far as I've learned from the forum, my temp and habit seem acceptable, but just wanted to see what others think of my habit. Trying to have a peace of mind...

I eventually will install the O2W type that comes with a Forester to help it warm up faster at cold start and cool down faster on a spirited driving. The temp reaches as low as -30C in the winter, so I hope the O2W cooler will help... I was enjoying driving with a couple of buddies, then it was little bit frustrating I had to back down to cool down.

Is there any Canadian vendor that I can buy such an O2W cooler? or should I find a shop located in the states?


Thank you.

AS far as your temps, they're fine. During autocross, I probably see temps as high as that after a run or back to back runs. Usually this is right be between the 190 and 270 marks on the 2017+ gauge, so about ~230.


Guys on the track see higher temps than this, up into the 260-270 range. Typically you're told if it hits 270, it's time to back off and if you're hitting that, time for an oil cooler.


If you're spirited driving / mountain roads and stock, you probably don't need an oil cooler.

This is anecdotal, but I personally feel that it will be difficult to dictate whether a specific oil would do poor or well without fully understanding the very specific study of tribology (which I don't).

But one could make a educated decision based on observations. My take on this is that the further you deviate from the 100C mark, the higher risk you undertake for your engine. This is no way by any means empirical but as engine oil properties are known as they are tested at 100C it is a good starting point. Given that coolant temps fully warmed up are at about 89-92C, and the existence of O2W coolers available which indirectly means a manufacturer allows an operating temperature of 89C.

Another thing to also look at is the relationship of temperatures and viscosity, which typically exhibit an exponential curve where the higher the temperature, its viscosity drops. A 5W30 oil has the weight of 30 at 100C where it is tested, but heating the oil any further will reduce its weight. By how much we have no idea, but the oil thinning out is a given.

The image below is from Penrite and shows a relationship of temperature vs viscosity (do note that all oils will demonstrate a different curve but as a general view):

https://i.imgur.com/zZfoybk.jpg

The fact that running oil hotter also degrades the oil faster, again we aren't able to quantify at which temperature and by how much, but as testing is done at 100C, one may assume that temperatures above that will see some amount of degradation, all things equal.

With the above said - if you are running 0W20 and have oil temps above 100C, you would be in a situation where you are aggressive with your car and your oil viscosity is lower than what the owner's manual recommends. Now how one interprets these combination of events whether if is still OK or not OK is up to them; one that is risk adverse may decide to go up one weight higher to ensure a larger weight buffer, or proceed as is. Running with a larger weight safety margin outweighs the benefits of reduced fuel consumption and engine response for me, hence I run 5W30. If I had mods to keep my oil temperatures in check at 100C in all situations, I would run 0W20.

Also I have the Forester O2W cooler as well, the only difference is that I'm in a tropical hot climate. Warmups are only slightly quicker, and on average during aggressive driving I see a 5C drop (I would hit 118C before and 113C after) but on track it would still soar above 120C, though it will cool the oil much faster during a pit-in break.

There's mixed opinions everywhere when it comes to engine oils, this is mine so do take it with a pinch of salt :)

Thank you. From what I've looked up, oil temperature above 240F may be the point where 0W20 looses the oil pressure that might be questionable in the high rpm range. The guys who ran into 260-270 range seem to go with a dedicated oil cooler to bring down the temp. Not that I have an evidence that 260F and above damages the bearings, but it seemed to me right to back off once I hit 240F.

Thank you. It's true that the oil weights are determined at 100C, but it seems far to easy to reach 100C whether you are on 0W20 or 5W30. My main concern is the potential to loose the pressure at 240F(115C) and above to avoid the damage to the bearings and the rest of the engine components. 240F seemed to me the reasonable temperature to back off little bit. It might be worth mentioning that I don't plan to track the car, only to drive spiritedly in the mountains from time to time.

It seems there are mixed opinions on the O2W cooler. It looks adequate to my driving purpose though.

Try eBay for the forester OC. You just need the part number for the cooler and bolt. Then order 5' vibrant 3/8 heater hose and 4 clamps.

I got mine around $250 shipped + $30 for the hose.
I haven't done a proper stress test but for daily use it's done a good job keeping oil between 205-215F. Knocked about 10F off my high temps if I was reving engine out on a hot day.

Just an FYI, my case:

MY2015, Europe Spec GT86

Header (Gruppe-S) + Drop-in Filter (Cosworth) + custom Stage 2 NA UEL Tune + no oil cooler + 0W_20 Eneos engine oil (API SN, Ilsac GF-5)

Location: Driving up a mountain road/pass, 2nd and 3rd gear, "full beans"

Result: Oil starvation and spun rod bearing resulting in damaged crankshaft and cylinder walls.

Probable cause: Excessive oil temperature --> oil film thinning and tearing --> metal - metal contact between cylinder #1 rod bearing and con-rod. Other parameters were excellent (fuel trims ok, MAF/MAP - ok, 0 knock/ 0 FLKC, IAM = 1, running quality RON100 gasoline).

Why: because I was dumb enough not to install the oil cooler sooner (air-oil) and running regular synthetic 0W_20.

Pic of damage:

https://i.imgur.com/uQtmKtS.jpg

Currently running a built engine + HKS GT2 SC + HKS Oil cooler + Oil Pressure monitoring system paired with Ecutek - CEL flashes if it detects a drop in Oil P under a certain predetermined value + frequent oil changes (Ravenol RCS 5W_40, PAO/Ester based engine oil with Vanlube W-324 Tungsten additive)

Do you have an oil pressure gauge installed? At 115 C, with 0w20 you oil pressure will be in the low 40s psi. Having both oil pressure and temp gauges installed, I would back off when I saw this. Oil temp/pressure is a function of rpm. Even having fun on a back road, it doesn't take long.
I read everything I could on here on oil, oil temp and oil pressure. I found out no one really knows what readings are bad for this engine. Low 40psi-probably bad. 132 C oil temp-probably bad. 0w20-depends on how your driving.
So, when having fun, if I saw oil temps at 118 C (just based on oil pressure), I backed off and let it cool down. This was frustrating. To help with this, I bought the oil/water cooler set-up (Cusco) installed it and set to driving. It does help the oil warm up faster. IT DOES NOTHING TO LOWER YOUR PEAK OIL TEMP. It does help the oil cool down faster. It may have taken a few psi off my oil pressures. Nice unit, now sitting in a box in my shed.
Then I bought a really nice Air to Oil cooler unit and installed. Wouldn't stop leaking. Yes I bought the proper wrenches, read about torquing flats, got flare savers. Wasn't leaking at the An fittings. No testing on this. It also is sitting in a box in my shed.
The I found this thread:https://forums.nasioc.com/forums/sho....php?t=2714154
Lots of good info. there. The Stribeck curve, etc. Read it all. To summerize, oil temp matters in regard to viscosity, match your oil to your temp. Cst.
Now I run a 5w30 Castrol C3. Oil pressure stays in the low 50s psi at 118 C the max temp I have seen. I don't back off to let it cool anymore since oil pressure stays up.
It should be noted here, that I had oil analysis done after every oil change. Blackstone Labs. All came back perfect: Stock car 0w20, backing off at 118C / Oil/water cooler, 0w20, backing off at 118C / 5w30 C3 no backing off.
I dont drive the car in winter so 5w30 doesnt bother me for cold starts and I like having that extra cushion on pressure.
My advice, an oil/water cooler certainly won't hurt and will definitely help with winter start-ups. But will it do enough to cool in the heat? Only your driving conditions will decide this. If it doesn't, summer/winter oil viscosity can be adjusted. If your planning on keeping the car for a while oil analysis is good for piece of mind.

I have basically identical setup. Did you monitor your oil temps at all?

Mine sits between 205--220f on daily and gets up near 240f if I hit a back road in the mountains.

The car is bone stock, so I only monitored the oil temp. It's true the oil pressure would have been the concern, so 115C/240F was the temperature I decided to back off to cool down. Good thing your oil analyses came back perfect in the similar situation of mine (stock car 0W20 and backing off at that temperature, although that doesn't mean I have my own evidence of the condition of my engine)

I understand the O2W cooler wouldn't lower the peak temp since it doesn't dissipate the heat as well as a dedicated oil cooler(O2A), but I'm sure you understand why I'm looking into O2W still.

Thank you.

Thank you. I was looking into buying separate parts online or the NED kit (which looked identical anyways), but didn't think of ebay for some reason...

The seller I bought from only had one cooler in stock but multiple bolts. Keep your eyes peeled if nothing pops up with the cooler part number.

Neds kit is conveniently packaged OEM kit. The cad conversion, duty and tax kills the value. A friend recently ordered it and ended up paying $320 via Ned's + $120 at the border.

Borrowed from here: https://www.ft86club.com/forums/showthread.php?t=91820

How much trouble is bleeding the coolant?

It wasn't much of an issue. Started afterwards and ran the engine for a minute with some light 3k revs. Turned off and Unscrewed the bleeder valve near the firewall to get air out. Topped off with deionized water. Run engine til fans kick in, let cool and check for air.

I ended up doing this twice as I swapped out the heater hose. I would suggest keeping an extra cooler gasket on hand for any situation where it needs to come off. The gasket swells and is a one time use.

IIRC the coolant circulation system eventually bleeds itself via the reservoir but to quickly relieve air there is a bleed valve close to the center of the engine firewall - however I don't remember the procedure off hand.

edit: @RToyo86 beat me to it

IMO, no. I've tracked mine since a few months after I bought it, probably put 32 track days on it, currently just over 50k on the odo, never ran an oil cooler. Every session oil temp climbs to just over 270F and holds there. Never had it climb from there even in 95F ambient temps. Personally, I don't think an oil cooler is necessary for occasional track usage and stints less than ~20-30 minutes. I do run 30 weight synthetic during track season.

Agree. IMO they are overprescribed and usually totally unecessary. *IF* I were to run one on a street car I would go with the OEM-type cooler OP mentions, which will ensure oil gets up to temp quickly.

I will be doing some tracking this season and will be curious to see where maxes out. I hit 265f before backing off multiple times.
A friend who ran the same forester OC on the same track has mentioned prior to install he was able to hit 290f on our local track with 0w-20 while not paying attention.
After the cooler his temps maxed out at 260f. 260f is still not ideal but I'll take a steady 260f over running hotter.

That and potential of warming up faster.
I have been watching oil temps near daily for the last week and a half with the cooler from cold start to 170F oil temps. During summer temperatures I don't see much of a difference warming the oil.

Coolant temps are about 30f ahead of oil temps which is in-line with no cooler from my experience.
Winter will be entirely different and I expect to see noticable difference there.

Thanks everyone!

I am not particularly fond of that data as I don't see an equal PSI/rpm correlation on my own car. Even running 0-20, I am pretty sure the oil pump cavitates. I build oil pressure till about 5800RPM and then it drops. I bought sensors for logging oil pressure and temp, waiting on my RPM reference sensor. I have a tool that plugs into these and will log the data.

FWIW I have been tracking my car on 0-20W with an oil cooler for 5-6 years. I regularly see oil temps in the 240-260F range. Buy good oil if you are hard on your car.

Thank you for sharing. I check my oil from time to time and tend to change the oil in a little bit short interval (6000km-ish) because of often short drivings and cold weather in the last winter.

I run 7500 mile oil change intervals.

Logging I will be using Innovate motorsports MTX gauges linked to an SSI-4 for RPM ref and going to a PL-1 datalogger.

Yeah, that's a bigger concern for me than oil temps at 270F, which don't bother me at all with good synthetic 30-weight oil. I'm sure you're familiar with this thread:
https://www.ft86club.com/forums/showthread.php?t=134863

Looking forward to seeing data! Are you running a KillerB or other aftermarket pickup tube? It would be great to see how effective that is at keeping oil pressure at higher rpm...

Yup! And anything above that range consider going to 30-weight. I would consider running 40-weight but for concerns about cavitation on the low-pressure side...

You know, I've always thought this but am not so sure now. A friend of mine got me into mountain driving and I've been logging some runs. On some fairly cool days (65F), I've seen peaks of 240-245 F oil on certain roads in extended driving. This is with a Perrin oil cooler and running E85. 245 F is about the same peak that I've seen at the track in 95 F days for comparison. I think it's due to the elevation (lack of air density) and overall lower speeds vs track (less airflow through the cooler). Mountain passes that use 3rd/4th usually peak around 10 F less (230-235 F) than those that use 2nd/3rd, I think due to the lower speed/airflow.

My recommendation would be that anyone who "spiritedly" drives 2nd/3rd gear mountain passes should watch their oil temps and evaluate.

Yeah I think good oil is essential. I used to pay attention to kV at 100 C, but HTHS viscosity (measured at 150 C) is probably the number to focus on for track use, particularly if running without an oil cooler and seeing high oil temps 260-290 F).

I am not running the KillerB pickup. The one they sent me didn't fit and I never got a replacement or refund. I guess IAG doesn't recommend running it for some reason either.

I still plan on testing before/after oil cooler temps/pressure and with and without oil cooler with 0-20 vs 5-30. I need to buy another gauge and the PL-1 will log it all. I just went a little deep in my parts budget this year so I am trying not to spend too much more money or I am not going to get to drive as much. The one part I am missing is showing up today so I might be able to get it roughly installed today and log the car on Saturday at the track.

Reading this link has got me reconsidering my oil choices... will pick something with a higher HTHS the next round for additional protection. It's easy to get ACEA C3s but I'm not fond of the oil intervals. Finding A3/B4s are getting harder nowadays, where they have >3.5 HTHS and >10 TBN.

From what I'm seeing from different manuals in different regions our cars would accept down to API SL, which most A3/B4s are in that category (many opinions out there say to just ignore API ratings though)

Just out of curiosity, if you're not seeing an equal PSI/rpm correlation on your own car, what kind of pressures are you seeing at certain temperatures? Because this data shows quite a wide range of PSI/rpm, so for you to be out of that data range completely would be very... interesting.

The issue is oil pump cavitation, or possibly a flow restriction in my setup. I have heard of others complain of cavitation as well but I see my oil pressure build up to 5800rpm and then drop. It is usually around 42-44psi at redline. If there is a cavitation issue like I am seeing then PSI/RPM is not going to correlate in the upper RPMs.

Ah yes, you did mention that. I am aware of this, I just misunderstood your correlation to the data. You're right, though the data may show this with the lowest psi dips, it is hard to know where it actually occurs in the RPM range (which is typically in the 6K+ RPM range as you say). Agreed that this is the most important issue with oil on this platform, not so much the temperatures themselves.

EDIT: This is actually why I have been most interested in following ZDan's case for some time now. Though it may be just luck, it is interesting to know that his car has held up so well over all the tracking he has done at high RPM's, probably with a lot of oil pressure creeping toward the pressures you mention.

Yeah, that is why I bought the equipment I did. I wanted to see real pressure numbers at RPM and temp. I didn't get it installed last night. I may try today but I still have a lot to do. The nice thing about the SSI-4 from Innovate, is that I should be able to just buy another pressure transducer and temp sender and wire it direct. I'd like to pull pressure temp data pre/post oil cooler. I have a spare timing cover(actually a whole other spare blown engine) that I am going to tap for additional senders. It just comes down to time.

Can someone explain what is cavitation? I think it's when air is introduced into the oiling system thus lowering pressure (air collapses). But why does this only happen when the oil gets hot?

My oil temp, I had to relocate my oil cooler so it’s 100% open, vented hood as well.. more
Air flow in & out.

I just started to wonder what you meant by good oil. I'm currently on Pennzoil Platinum 0w-20, which says full synthetic. Is there any other property that I need to look out for other than being fully synthetic and the weight of the oil?

Thank you.

You can wade WAAAYYYY into the weeds with this question looking at kinematic viscosities, shear stability, and a host of other technical detail. Pennzoil Plat is, by every definition I've seen a good oil. I use it in my car and the engine seems marginally quieter on it than the Subie shop oil. For my money, any name brand full synthetic in 0w-20 should be fine. Depending on the severity of the service the car sees (very hot ambient temps, tracking, beating the shit out of it) you may want to go up a viscosity grade (e.g. 5w-30). Just change it regularly and enjoy the car.

Just keep in mind, that every oil has a religion based on it and its believers will defend it to the death.

As Capt Spaulding said, there can be so much to consider if you want to dig into it. Skip to the basics - oil weight and a reputable brand. Another thing to consider is GF-6 oil came out fairly recently, so it could be useful to upgrade to the latest and greatest oil. It should always have a mark somewhere stating whether it is GF-5 or GF-6 rated. It's likely that most oils you see (especially online) are already selling the latest product, so no searching will really be necessary.

IIRC, the one I bought has the GF-6 rating. Prior to buying the oil, I looked up the new rating, and it sounded more appealing than the GF-5 rating, so I went with it.

https://www.canadiantire.ca/en/pdp/p...-0289329p.html

Thank you.

So from what I have read, and if I understood the article, cavitation is caused by “bottleneck” somewhere in the system resulting in high and low pressure. This causes the oil to “bubble” (oil boiling going from liquid to gas and back to liquid). In the case of our system, the thread suggests that the stock FA oil pickup tube is the bottle neck resulting in cavitation. The suggested remediation is the killer B pick up but I have not seen much info about this from my search. Am I on the right track?

Thanks.

Yes, except it is not so much that the threat suggests the pickup tube to be the bottleneck of our system. It is more that this part may help some in certain conditions and is also a fairly easy part to replace as a potential solution. Unfortunately, there is no clear indicator through the research that cavitation can be avoided with the killer B pickup, or even reduced for that matter. The idea is that it may certainly help prevent it.

Currently the best solution to avoid the drop in pressure at high RPM's is proper cooling. Whether it be an oil cooler or hood vents or a combination of multiple things, if you are able to keep your temps near factory spec for oil temps and pressures, then you should be avoiding the problem. Many have been trying to find other ways around it, with great potential, but nothing has fully resolved this problem with the twins - and I don't believe it ever will be resolved as it is more of a design flaw so to speak, rather than a simple part replacement to fix it.

The Killer B pickup has the potential to help, if you get one that is made right. There are other issues in the system that cause problems highlighted by that thread. He did a lot of porting and matching passageways to improve flow.

I wish there was an easy way to add the WRX oil pump to our engines but it wouldn't work without a ton of modification, and it would exaggerate the cavitation issue. So it would not really be a solution unless you updated the whole system.

It's strange though as I have seen some members that has regularly track driven their cars go without issues for years. I seem to assume that most spun bearing issues are related to the valve spring recall rather than oil temp related. I am sure it's ideal for lower oil temps but I have also read that adding an oil cooler also reduces oil pressure negating the benefits.