MY02 WRX - Oil Pressure with Mobil 1: 15w50 Motorsport Oil
26 February 2011, 09:53 AM
#31
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As a note on thicker oils... My car currently runs 10-50 (almost exclusively track days, and even then not many per year).
On cold startup, it takes about .5-1 seconds before the oil light goes out, and this nver used to happen on thinner oils (e.g the 5-40 i used back when the car was a daily drive).
For my car and my circumstances, i'm ok with the way the oil performs on cold starts, but for a daily drive it cant be good, so careful that youre not getting sucked into some "its used in motorsports so it must be better" kind of argument - its probably not true
On cold startup, it takes about .5-1 seconds before the oil light goes out, and this nver used to happen on thinner oils (e.g the 5-40 i used back when the car was a daily drive).
For my car and my circumstances, i'm ok with the way the oil performs on cold starts, but for a daily drive it cant be good, so careful that youre not getting sucked into some "its used in motorsports so it must be better" kind of argument - its probably not true
26 February 2011, 10:05 AM
#32
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As a note on thicker oils... My car currently runs 10-50 (almost exclusively track days, and even then not many per year).
On cold startup, it takes about .5-1 seconds before the oil light goes out, and this nver used to happen on thinner oils (e.g the 5-40 i used back when the car was a daily drive).
For my car and my circumstances, i'm ok with the way the oil performs on cold starts, but for a daily drive it cant be good, so careful that youre not getting sucked into some "its used in motorsports so it must be better" kind of argument - its probably not true
On cold startup, it takes about .5-1 seconds before the oil light goes out, and this nver used to happen on thinner oils (e.g the 5-40 i used back when the car was a daily drive).
For my car and my circumstances, i'm ok with the way the oil performs on cold starts, but for a daily drive it cant be good, so careful that youre not getting sucked into some "its used in motorsports so it must be better" kind of argument - its probably not true
Tell me why and prove the statement and I would gladly listen.
26 February 2011, 12:49 PM
#33
Obviously, what oil you put in your car is ultimately your own choice.
That said, the Subaru service manual will give you some kind of indication as to what weight oil you should consider. 5w-30 being the oil that comes prefitted from the factory.
This is straight from the service manual:
It also has a little diagram where it recommends 5w-30 oil for cranking temperatures of: -30C to 40C
And alternatively 10w-30 and 10w-50 for cranking temperatures of: -20C to 40C
Also, consider your environment, i.e. temperature at cold starts, which is one of the most stressful times on your engine.
I.e. you want this to be as harmless as possible. You can do this by looking at their cold viscosity and Pour Point rating, gelation points, etc etc etc, and make up your own mind.
For example, Caterpillar has a cranking temperature recommendation in relation to oil weight, that goes like this:
0w20 -40C to 10C
0w30 -40C to 30C
0w40 -40C to 40C
5w30 -30C to 30C
5w40 -30C to 40C
10w30 -17C to 40C
10w40 -17C to 50C
15w40 -15C to 50C
Obviously, much less to consider in the UK, as your winters are "MILD", a 15w or 10w oil should be just fine, but here it can (and does) get to -30C and colder, hence running different oils summer and winter. :P
Now, wether or not you shoud run say 0w-50 oils all year, as they are clearly better than 15w-50 oil, or whatever else, is a completely different tin of worms.
Personally, Visocsity Intensifiers aren't all they are cracked up to be, and I like to have my cold and warm weight "closer" together, as the oil doesn't seem to deteriorate as rapidly. Just my 5p though.
That said, the Subaru service manual will give you some kind of indication as to what weight oil you should consider. 5w-30 being the oil that comes prefitted from the factory.
This is straight from the service manual:
The proper viscosity helps vehicle get good cold and hot starting by reducing viscous friction and thus increasing cranking speed
Note:
If the vehicle is used in areas with very high temperatures or for other heavy duty applications, the following viscosity oils may be used: API standard: SM or SL SAE Viscosity No.:30, 40, 10w-50, 20w-40, 20w-50.
Note:
If the vehicle is used in areas with very high temperatures or for other heavy duty applications, the following viscosity oils may be used: API standard: SM or SL SAE Viscosity No.:30, 40, 10w-50, 20w-40, 20w-50.
And alternatively 10w-30 and 10w-50 for cranking temperatures of: -20C to 40C
Also, consider your environment, i.e. temperature at cold starts, which is one of the most stressful times on your engine.
"It's true, 80 to 90 percent of your engine's life is consumed by cold and dry start ups. Engines usually shut down hot, at which point the oil is thin and drips away from the bearing and other "friction intense" areas. Gradually the oil cools, thickens and becomes difficult to pump. When starting an engine, the lubrication process involves filling all oil galleys, filling the filter, pressurizing the rod, main and cam bearing as well as the entire valve train (filling the lifters and lubricating the cam lobe and rocker arms). Unfortunately, your engine is running while this lubricating process and is meshing metal against metal, hence massive engine wear takes place."
For example, Caterpillar has a cranking temperature recommendation in relation to oil weight, that goes like this:
0w20 -40C to 10C
0w30 -40C to 30C
0w40 -40C to 40C
5w30 -30C to 30C
5w40 -30C to 40C
10w30 -17C to 40C
10w40 -17C to 50C
15w40 -15C to 50C
Obviously, much less to consider in the UK, as your winters are "MILD", a 15w or 10w oil should be just fine, but here it can (and does) get to -30C and colder, hence running different oils summer and winter. :P
Now, wether or not you shoud run say 0w-50 oils all year, as they are clearly better than 15w-50 oil, or whatever else, is a completely different tin of worms.
Personally, Visocsity Intensifiers aren't all they are cracked up to be, and I like to have my cold and warm weight "closer" together, as the oil doesn't seem to deteriorate as rapidly. Just my 5p though.
Last edited by DisoDisp; 26 February 2011 at 01:02 PM.
26 February 2011, 01:23 PM
#34
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Well DisoDisp that's a very detailed "5p worth" alright! 
But again the manuals, etc, state "Unfortunately, your engine is running while this lubricating process and is meshing metal against metal, hence massive engine wear takes place" but again it's only a statement. Like everyone posting on here, it's all talk. Of course I too have no proof that my engine is not wearing out and "and is meshing metal against metal, hence massive engine wear takes place." lol.
I have been blessed as my car always starts first time in the morning. Yes it is garages and yes in winter it can struggle to start. That's when it needs an oil change to a lower W oil and let me see the difference, then I would change! I am a logical person so I need proof or examples. Thx for the info though, very detailed. And -30? Errr, not for me. Haha.
But again the manuals, etc, state "Unfortunately, your engine is running while this lubricating process and is meshing metal against metal, hence massive engine wear takes place" but again it's only a statement. Like everyone posting on here, it's all talk. Of course I too have no proof that my engine is not wearing out and "and is meshing metal against metal, hence massive engine wear takes place." lol.
I have been blessed as my car always starts first time in the morning. Yes it is garages and yes in winter it can struggle to start. That's when it needs an oil change to a lower W oil and let me see the difference, then I would change! I am a logical person so I need proof or examples. Thx for the info though, very detailed. And -30? Errr, not for me. Haha.
26 February 2011, 03:07 PM
#35
Aye, got a little off track, but it's something we debate a lot at work :P
And yes its all "talk", on this level, but car/machinery and oil manufacturers have pretty detailed information, and real world tests to support their claims. I know Shell test all of their oils in massive detail, as far as to make sure they are able to squeeze every last bit of performance out of Ferrari's F1 engines without sacrificing on protection.
Granted, they only experience warm starts, and hence it's a bit of a non issue.
And yes its all "talk", on this level, but car/machinery and oil manufacturers have pretty detailed information, and real world tests to support their claims. I know Shell test all of their oils in massive detail, as far as to make sure they are able to squeeze every last bit of performance out of Ferrari's F1 engines without sacrificing on protection.
Granted, they only experience warm starts, and hence it's a bit of a non issue.
28 February 2011, 09:39 AM
#36
I am not making any of this up, it is all based on fact and research done by oil manufactures and car manufacturers. Just search the internet, even better pick up the phone to Mobil, Castrol, Fuchs, Comma, Millers, Morris, Silkolene, Motul, Total, Shell, Elf... The list goes on and they all have a technical dept, ask them what is better for your engine on cold start(as its a daily driver) 15w, 10w or 5w and ask them why. Perhaps it coming from the horses mouth may help.
I am not saying you have to use a better flowing oil from cold, but at least accept the pros and cons of using differerent cold crank viscosities on a daily basis befor you make your mind up.
Cheers
Guy.
28 February 2011, 09:59 AM
#37
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What I am referring to is the comparison of a 5w against a 15w in the same circumstances. I do accept the 5w is thinner, there is no debate there to be had. What I am writing against is the quotes about damaging engines using a thicker oil. Its thicker therefore quote "is meshing metal against metal, hence massive engine wear takes place."
I may well move to a 10w oil in my March service, but then again, I may not. My car is a daily driver and has covered 102k miles. If it did pack up and it could be proven it was down to using the wrong oil, then I could and would come on here and "eat lots of humble pie" but all I am saying is every Subaru garage has used the 10w or 15w that I have been too. It will actually be a good comparison if I were to use the 10w as I do have oil pressure and temp gauges and so could do a direct test comparison on that.
Hmmm, I feel a test coming on! LOL.
I may well move to a 10w oil in my March service, but then again, I may not. My car is a daily driver and has covered 102k miles. If it did pack up and it could be proven it was down to using the wrong oil, then I could and would come on here and "eat lots of humble pie" but all I am saying is every Subaru garage has used the 10w or 15w that I have been too. It will actually be a good comparison if I were to use the 10w as I do have oil pressure and temp gauges and so could do a direct test comparison on that.
Hmmm, I feel a test coming on! LOL.
28 February 2011, 10:11 AM
#38
Cool, do a test. I will be interested in what you find.
Using a 15w will not mash bits of metal together it will just not flow as well at start up as a 5w or a 10w as you agree. The advantage to this is it gets around the engine quicker, warms up quicker and thus many of the additives in the oil desgined to look after your engine come to life quicker as they respond to temp.
As I said earlier, track car no problem. But a daily driver on a cold morning there are advantages to using a better flowing oil, it is up to you if you take this advantage but moving from 15w to 10 would be a good idea with your use.
Cheers
Guy.
Using a 15w will not mash bits of metal together it will just not flow as well at start up as a 5w or a 10w as you agree. The advantage to this is it gets around the engine quicker, warms up quicker and thus many of the additives in the oil desgined to look after your engine come to life quicker as they respond to temp.
As I said earlier, track car no problem. But a daily driver on a cold morning there are advantages to using a better flowing oil, it is up to you if you take this advantage but moving from 15w to 10 would be a good idea with your use.
Cheers
Guy.
28 February 2011, 05:07 PM
#39
Given that the oil lamp goes out at some ridiculously low pressure, i dont think thats a very good sign, and if i was a daily driver, i would personally use something thinner.
The components will still have an oil film on them since last time the engine was running, so it may do no harm at all in reality, but i dont think it looks like a good sign.
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