Anyone else switch to thinner oil during winter seasons?

[Rick L]

Anyone else switch to thinner oil during winter seasons? I use 0w-40 during spring, summer, and fall and switch to 5w-30 during winter. Recently, I switched to 0w-30 (new Mobil 1 that’s out). Or do you stick with same weight year round?

[Jehu]

Just added Royal Purple 5w30 to the 540..

[Torque]

I used to run 20w50 in the summer and 10w40 winter in the 535i; didn't have any issues even the few days we had 0 degree temps last winter.

[BMW4LIFE]

I have been running 10-40 high miles Mobile 1 for some time now in all 4 seasons and everything is awesome here

i want to run the 0-40 but i have a small leak and am afraid that it will become worse with the thinner oil =/

still curious about the performance difference when it comes to lubricating the engine in these cold starts...then again i live in ca so it doesnt get that cold...around 39 F at the worst in my area

[Bo525i]

I run 5-50 year round here in scandinavia!

[Rick L]

Correct me if wrong but doesn't "W" in 0w-40 means "winter" grade? And actual weight of the oil for 0w-40 is 40. "0w" means it can flow at that specification. I have always used lower weight 30 or *w-30 in winters and *w-40 for all other seaons.

Also, just wondering how many members here are using "High Mileage Oil"? I have mixed feelings about using this. I afraid it might have adverse effect.

[Ferret]

Isn't 0w and 5w the same actual weight?

I seem to remember reading somewhere that 0w is actually 5w with a better temperature range.

"w" means weight, surely?

We're having fun with the temperatures here at the moment, had to actually put the 8 away for the week because the roads are like oiled glass at the moment!

[ArnZ!]

Just so you guys know the first number is the weight of the oil at 40 degrees Celsius. The second number is the weight of the oil at operating temp, 100 degrees Celsius.
Just think of the numbers as "oil thickness at startup and oil thickness at operating temp."

So a 20w50 will be thicker at start up then a 10w50 would but when they both get upto operating temp they are both the same. Same with 0w40 and 10w40 and so on.

The real measurement of the oil weight is in Centistokes. So for example, the oil i use in my car is a 10w50 and its really a 131 cSt when cold and 18.8 cSt when at operating temp. The old oil i used was a 20w60. Which was 24 cSt when cold and 24.4 cSt when at operating temp.

The SAE grade of oil is more of a rough indication of what weight in cSt the oil is. So an Xw50 oil weight at operating temp is roughly somewhere between 15 cSt and 19 cSt. A Xw30 oil weight will be somewhere between 10 cSt and 12 cSt and so on. These are just figures off the top of my head.

So when choosing an oil you would want something thats thin and startup and thick enough at operating temp.

[Tiger]

Geez... are you all that far behind in oil technology? Sounds like granpa's rule of thumb.

0W is thinner than 5W... so how is 5W thinner than 0W? It is not.

30, 40 and 50 or even 60... thicker is better? Not really. We don't run our engine 100% racing duty cycle.

Which offer better protection from wear and tear? 50? Nope... 30 does.

Which gives better fuel mileage? 0W30 or 10W40... at least most of you will get this right... 0W30.

Which offer more protection at high RPM? 5W30 synthetic or 20W50 dino? Synthetic wins. How about this one... 5W30 synthetic vs 20W50 synthetic? Thinner wins...

There are lots to learn and it pays for you to read up on facts about oil...

[Rick L]

Thanks for clarifying this guys. I was told by many to use thinner oil, both cold and operating temp, for winter if your climate deeps below freezing point. Or have I just switched all this time that had no effect either way? But maybe it's just in my head but I do think my engine runs better with thinner oil during cold winters.

And I'm stuck using 10w-60 for my M3 regardless of climate condition... So called only recommended fluid by BMW, Castrol TWS 10w-60.

[Tiger]

M3 is special so what the factory said accurate enough. It does get cold in Germany too.

[bubba966]

Usually run Amsoil 0w-30 in my M-Sport. Last change I tried the Delo Synth 5w-40 as I've heard it runs nice in E34's. It's ok, but I like the 0w-30 Amsoil much better. Too bad the Delo is $17/gallon at Costco while the Amsoil is $12/quart. Will go back to the Amsoil next time.

Run the 0w-30 year round. Don't feel like running 0w-20 in it so no need to change it in the cold to something different.

[Tiger]

That's cheap... Delo Synth 5W40... it is mainly designed for diesel but works well in gas engine too... the 30 is what makes the engine revs much easier.

[632 Regal]

I am using M1 15w50 right now. No real reason besides I cant find 0w40 anymore. Used to use 5w30 M1 but since they changed it from full synthetic to a mystery oil (thanks to Castroll) Id rather use the 15-50 that claims to be a full synthetic.

Used to run M1 5w30 in the racecar, now here we are talking severe duty and I never had any problems at all. 7000 rpm shift point with 462 inches is severe in my opinion.

[Rick L]

Do you know if they changed 0w-40 as well? Meaning it is not full synthetic? I always thought you suppost to use thicker oil in racecar or for track use?



I am using M1 15w50 right now. No real reason besides I cant find 0w40 anymore. Used to use 5w30 M1 but since they changed it from full synthetic to a mystery oil (thanks to Castroll) Id rather use the 15-50 that claims to be a full synthetic.

Used to run M1 5w30 in the racecar, now here we are talking severe duty and I never had any problems at all. 7000 rpm shift point with 462 inches is severe in my opinion.

[philbyil]

Even when we lived in Chicago, I kept Mobil1 15w50 in the GQ year round without any issues at all. I do have an Oil Pressure Gauge on the car and it showed no issues either ;)


Anyone else switch to thinner oil during winter seasons? I use 0w-40 during spring, summer, and fall and switch to 5w-30 during winter. Recently, I switched to 0w-30 (new Mobil 1 that’s out). Or do you stick with same weight year round?

[Rick L]

Thanks. You have oil pressure gauge in your E34 or you mean on a different car? I think BMW should add this in their instrument cluster or at least in the M models.


Even when we lived in Chicago, I kept Mobil1 15w50 in the GQ year round without any issues at all. I do have an Oil Pressure Gauge on the car and it showed no issues either ;)

[632 Regal]

I have not found bad crankup speed in any synthetics. normal oil yes. please tell me different as it is 20 degrees here and i crank normal.

[philbyil]

I installed a Hartge Gauge cluster with VDO instruments a few years back.
I used an adapter at the existing idiot light take-off that allows you to use both a temp and pressure sensor for the gauges (and keeps the existing idiot light!) plus I added a voltmeter. Looks really sharp :)



Thanks. You have oil pressure gauge in your E34 or you mean on a different car? I think BMW should add this in their instrument cluster or at least in the M models.

[repenttokyo]

i run castrol syntec 5w50 year round - it helps prevent noisy lifters in my car. also helps in the miata as well.

[genphreak]

Jeff,

Why use 10W30 oil in the racecar? Doesn't lighter oil mean a faster engine, but more wear if not designed for it? I tried 10W40 in the M50 once, the lifters were noticably loud on a hot day under load- changed back fo 15W/50 and all was good, so figured that I should always use an oil with the same upper rating, but using one with a lower cold rating was always better as it improved protection at startup (esp when the ambient temp reduces in Winter)- ie 15W/50 instead of 20W/50 but not 15W/40.

[genphreak]

I have not found bad crankup speed in any synthetics. normal oil yes. please tell me different as it is 20 degrees here and i crank normal.(As Jeff knows) Cold oil won't slow crank up speed. It'd break the oil pump chain if the pump was holding back anything like starter motor torque.

Cold crankup is going to be voltage related (esp. in cold conditions).

[Rick L]

I always thought 50 weight is too thick for M50. But seems like many here use it.

[Rick L]

Do you have picture? I'm curious to see how it looks.


I installed a Hartge Gauge cluster with VDO instruments a few years back.
I used an adapter at the existing idiot light take-off that allows you to use both a temp and pressure sensor for the gauges (and keeps the existing idiot light!) plus I added a voltmeter. Looks really sharp :)

[philbyil]

I'll take a piccy...it really looks great!

FYI - 15w50 is specified in the 525i owners manual ;)


Do you have picture? I'm curious to see how it looks.

[632 Regal]

Jeff,

Why use 10W30 oil in the racecar? Doesn't lighter oil mean a faster engine, but more wear if not designed for it? I tried 10W40 in the M50 once, the lifters were noticably loud on a hot day under load- changed back fo 15W/50 and all was good, so figured that I should always use an oil with the same upper rating, but using one with a lower cold rating was always better as it improved protection at startup (esp when the ambient temp reduces in Winter)- ie 15W/50 instead of 20W/50 but not 15W/40.

the M1 10-30 back then was full synthetic. Light oil means less windage and more power, I found when rebuilding at the end of season that I acquired zero wear except the cylinder cross hatch was smooth even tho I could still see it. Do to a serious virus (divorce) the new 632 engine never made it into play, at around that time M1 and Castrol went to court and Castrol was awarded with legal advertising of pure synthetic which wasn't synthetic, M1 obviously followed suit. If the 632 project did pan out I would have run a similar weight in Royal purple or other fully synthetic variety.

Normal oils just do not cut the musterd for me, been racing since '80 and blew many engines in oil related mishaps until I finally could acquire a synthetic oil, never EVER an oil related problem since. The virus's truck blew a head gasket and begged for me to rescue her and the truck which i did. Drove it with no water for 45 miles on the freeway, the oil had +30K on it. arriving at the shop/barn the exhaust manifolds were glowing cherry red, when cooled were a tinge of purple. Disconnected the battery and called it a day. Every wire burned or melted including the alternator and starter.

I disassembled the engine looking to find it toasted, it was perfect. Replaced the head and was good to go again, never did change that old oil LOL.:D

[bsell]

(As Jeff knows) Cold oil won't slow crank up speed. It'd break the oil pump chain if the pump was holding back anything like starter motor torque.

Cold crankup is going to be voltage related (esp. in cold conditions).

I'll give you the weak battery at cold temps (20F and lower) causing some of the slow turnover. I think we've all seen 'cold' oil not flow, or flowing like molassas. I figure the slow crank is 50/50 weak battery/thick oil.

Nice couple posts talking good things about oil here:http://www.ipgn.com.au/forum/showthread.php?t=33453

DIY pour point determination video:http://www.youtube.com/watch?gl=US&v=8lGqOulUVq8