20w50 or 15w40 Brad Penn year round in Chicago?

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9
Location
Chicago
Hi there, I own a 1986 BMW 325e and am moving up to Chicago from down south. Was previously using 20w50 all year round due to the temps. Can I get away with 20w50 year round in Chicago or is a 15w40 more appropriate? Will be using Brad Penn Partial Synthetic oil. This car is a 2nd vehicle/not a daily driver and would not be driven regularly in the winter, only when weather permits. I really do not want to switch between oil viscosities based on time of year so wanted everyone's opinion on what to run year round. Thanks
 
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2,500
Location
Dallas, Texas
+1 on the 5w-40. Rotella 5w-40 is very good stuff you can find relatively inexpensive down here in Texas. Or maybe a 0w-40, I know M1 European Formula is good stuff too. Any name brand 5w=40 or 0w-40 will protect you year round. You can't say tath about a 15w-40, and definitely not a 20w50.
 

cnowak1

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Messages
9
Location
Chicago
I would like to stay with Brad Penn due to the ZDDP. Only other oil I have used in the car is Valvoline VR1. I know that is important in these older BMW engines. They unfortunately do not make a 5w40. I have heard great stuff about the Rotella as well. When I used to live in Chicago before, the car was my daily driver so I used lower viscosity in winter. But it being my 2nd car now, I do would rather not switch.
 
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40,823
Location
Great Lakes
You could try Chevron Delo 5w-40 - it has nearly the same amounts of zinc and phosphorus as Brad Penn, and can be had cheaply at Walmart. But even the Rotella T6 5w-40 suggested earlier should work just fine. Me thinks starting a cold engine at 0F with 15w-40 oil in it will do more harm than running 5w-40 with slightly less ZDDP. Why do you think this engine requires a ton of ZDDP?
 

cnowak1

Thread starter
Messages
9
Location
Chicago
Sounds good thanks for the suggestions so far...Also, what outside ambient temps is a 40 oil good for? Seems like it varies based on most owners manuals I have seen. I know the 20w50 is good til probably well past 100 F. As the motor is a flat tappet, the ZDDP provides many benefits I have heard. Since it has non hydraulic lifters and the rocker arm that sits directly on the cam.
 
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40,823
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Great Lakes
Originally Posted By: cnowak1
Also, what outside ambient temps is a 40 oil good for?
40-grade will do you just fine in Chicago summers. You're new here, and you seem to have the typical aversion to thinner oils. That's understandable. Stick around long enough, and you'll be running 20-grade oils in your cars. smile Welcome to BITOG!
Quote:
As the motor is a flat tappet, the ZDDP provides many benefits I have heard.
API SM/SN has lowered the limits on ZDDP, but these limits only apply to 20 and 30-grade oils. Most of the 40-grade oils still have plenty of ZDDP, especially the HDEO oils mentioned above like Rotella and Delo.
 

OVERKILL

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46,185
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Ontario, Canada
Originally Posted By: cnowak1
I would like to stay with Brad Penn due to the ZDDP. Only other oil I have used in the car is Valvoline VR1. I know that is important in these older BMW engines. They unfortunately do not make a 5w40. I have heard great stuff about the Rotella as well. When I used to live in Chicago before, the car was my daily driver so I used lower viscosity in winter. But it being my 2nd car now, I do would rather not switch.
M1 0w-40 has more than enough ZDDP for your application, it isn't like you are running a pair of Lunati voodoo sticks underneath your valve cover pushing against 500lb valve springs smile
 

cnowak1

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9
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Chicago
Thanks for the great replies. Haha and yup I guess I like thinner oils but am scared about using them in these motors for some reason. Had a few of these older BMWs and it is always drilled into your head to use 20w50 and heavier stuff. Obviously, when the manual was printed in the 80s there were not many great oils to choose from. Too many choices these days
 

OVERKILL

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M1 0w-40 isn't thin, it is just thinner than 20w-50. And it doesn't thicken as much as the temperature drops. It would provide you with more than enough protection.
 
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1,116
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midwest
I use 20w50 in summer and 10w40 or 15w40 winter on my eta engines in central IL, about 2 hrs south of Chicago. For the one that gets driven year round it's 15w40 most of the time. They'll run on anything really.
 

Nick1994

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If your car's cooling system is functional there's no reason to use a thicker oil in the summer. Your engine operates at the same temperature regardless once up to temperature. Use Mobil 1 0w40
 
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3,117
Location
Virginia
Originally Posted By: OVERKILL
Originally Posted By: cnowak1
I would like to stay with Brad Penn due to the ZDDP. Only other oil I have used in the car is Valvoline VR1. I know that is important in these older BMW engines. They unfortunately do not make a 5w40. I have heard great stuff about the Rotella as well. When I used to live in Chicago before, the car was my daily driver so I used lower viscosity in winter. But it being my 2nd car now, I do would rather not switch.
M1 0w-40 has more than enough ZDDP for your application, it isn't like you are running a pair of Lunati voodoo sticks underneath your valve cover pushing against 500lb valve springs smile
Amen. M1 0W-40 is all you need year round. Simple and cheap.
 
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819
Location
Chicago, IL
Last winter Chicago had a average cold temp actually colder than Anchorage Alaska. Also, you will find a lot of "stop and go" driving and encounter probably the most aggressive drivers in the nation.
 

cnowak1

Thread starter
Messages
9
Location
Chicago
Haha yea bad drivers....however I lived there all my life pretty much so used to it. I am actually coming from New Orleans now, home of the other most terrible drivers and outrageous insurance! Regarding oil "pour points", how does that compare to "pumping point temps"? Not everyone lists those statistics. Just for example purposes, some partial synthetics have a -16 and most synthetics have around -40 to -60. How does that correspond with actually starting your car up in the cold? Thanks!
 
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Messages
188
Location
so cal
I too am a fan of brad penn. I would run their 10w-40 penn grade 1 year around. An oil with lots of zinc like a diesel oil is not the whole picture, it's the balance of zinc and other adds that matters. Dan
 

cnowak1

Thread starter
Messages
9
Location
Chicago
Any experiences going to a synthetic on these older motors? I know they were not designed per say to run on synthetic, only dino oil....but obviously oil technology has improved since the 80s. I know switching does NOT cause leaks as many think. I am more concerned of it being a used on a flat tappet motor so just wanted some input. Thanks again, I am learning quite a bit.
 
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