Mixing OW-40 and 15W-50 in my 1.8T VW. What are your thoughts?

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61
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Portland, Or
I have wanted to try Ow-40, but I have two major concerns. 1.) film stength once the oil gets 3000 miles + and 2.) Oil sleeping through the rings when the oil is cold.. After all, OW is freaking light.... Too light for those of us who drive very hard! I have been tempted to just screw it and run 15W-50 through my 1.8T. The only thing that holds be back is the cold viscosity. So, I was thinking if I mixed 0W-40 & 15W-50 50%/50% I'd eand up about a 7.5W-45. Sounds perfect to me! Very tough and probably long lasting. What do you guys think?
 
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Did that exact same mix with M1 in my SAAB 2L Turbo. I've been very happy with it. I'm glad to see someone taking care of their 1.8T. It's a great motor, but it will not stand up to a lack of maintenence very well.
 
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404
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Palatine, IL
quote:
Originally posted by carrera79: Did that exact same mix with M1 in my SAAB 2L Turbo. I've been very happy with it. I'm glad to see someone taking care of their 1.8T. It's a great motor, but it will not stand up to a lack of maintenence very well.
Am i murdering my 2003 Audi A4 1.8T with GC 0W-30?? [Embarrassed] The dealer uses 5W-30 Valvoline [freaknout] [freaknout]
 

rekced

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Portland, Or
That's why I don't go to the dealer. Does anyone have a reason I shouldn't run 15W-50 trough my 1.8T? Maybe I should run straight 15W50 in the summer and run the mixed stuff in the winter. The coldest it ever gets here in the winter is 20degreesF or so. Should the 50 weight be okay for my turbo? [ May 31, 2004, 10:22 PM: Message edited by: rekced ]
 
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CT
quote:
After all, OW is freaking light
I think you are mistaken on how oil viscocity works. 0W-40 (or any oil) is the thickest when it's cold, and thins out to a 40 weight when it is warmed up to 100C. You are correct that 0W-40 does have a tendency to shear down to a 30 viscocity with extended oil drains. Mixing those two will do no harm but why not save yourself the trouble and use M1 5W-40. Truck & SUV or Delvac...same great stuff! Plenty of additives for extended drains and will not shear down like oW-40 can.
 
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College Dorm...
Let's clear this up...M1 0w-40 "shears down" quickly because to earn the tough specs it meets, it needs to achieve high fuel economy over the long run as well as resist thickening out of grade. If you'll run it on out, you'll find that it will remain a 40 weight. BMW LL-01 Daimler Chrysler 229.5 Opel Long Life Service Fill GM-LL-A-025 Opel Diesel Service Fill GM-LL-B-025 Etc, etc... M1 0w-40 is not gonna seep through your rings when cold (that is pretty funny though!) and film strength will remain very high...this oil is designed for the long-run.
 

rekced

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61
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Portland, Or
thanks for the info guys! I just want to double check that nobody objects to me mixing the oil. It's not hard to do, I just bought 3 quarts of each. Oh, and will straight 15W-50 be okay in the summer? I'm just kind of scared of 30 weight because I drive so hard. [ June 01, 2004, 02:16 AM: Message edited by: rekced ]
 

rekced

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Portland, Or
Because 0W-40 shears down to a 30 weigth for a while as I understand it. I did a search a long time ago and found that it'll go from 0W-40 down to OW-30, then back to 0W-40... 0W-30 makes me a little nervous with my driving habbits. If I could safely mix it i think it'd be a perfect balance. 7.5W-45. I have an a-load of mobil products around the house, so buying anything else is kinda out of the question. It comes down to 15W-50, OW-40, or a mix. [Wink]
 
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40,706
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Great Lakes
quote:
Originally posted by therion: Am i murdering my 2003 Audi A4 1.8T with GC 0W-30??
Do a UOA and find out. [Wink] AFAIK, GC 0w-30 (Castrol SLX) is a factory fill for most audis these days. Starting next week, I'll be running SLX in my 1.8T as well. I also had good UOA results with M1 5w-30, so I see no evidence that this engine requires anything thicker than a 30-weight. [Cheers!]
 
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40,706
Location
Great Lakes
quote:
Originally posted by rekced: I have wanted to try Ow-40, but I have two major concerns. 1.) film stength once the oil gets 3000 miles + and 2.) Oil sleeping through the rings when the oil is cold.. After all, OW is freaking light.... Too light for those of us who drive very hard!
Sigh... how is it "freaking light"? When you drive hard, the oil is at its operating temps at which point it's as light as any other 40-weight oil. And the fact that it's a 0w oil just means that it'll still flow decently when it's -20F outside, but it is definitely nowhere near being "light", if by light you mean water-like. As far as grade mixing, why not just use M1 5w-40 instead?
 

rekced

Thread starter
Messages
61
Location
Portland, Or
quote:
Originally posted by Quattro Pete:
quote:
Originally posted by rekced: I have wanted to try Ow-40, but I have two major concerns. 1.) film stength once the oil gets 3000 miles + and 2.) Oil sleeping through the rings when the oil is cold.. After all, OW is freaking light.... Too light for those of us who drive very hard!
Sigh... how is it "freaking light"? When you drive hard, the oil is at its operating temps at which point it's as light as any other 40-weight oil. And the fact that it's a 0w oil just means that it'll still flow decently when it's -20F outside, but it is definitely nowhere near being "light", if by light you mean water-like. As far as grade mixing, why not just use M1 5w-40 instead?

Yes, "freaking light!" When I say drive hard, I mean 95 degree days in the summer with the AC on and redlining every gear with an APR chip. I always figured the oil would sheer down in no time because of all the viscosity improvers. That's why I said that, not because I think I'll actually be driving around on 0 weight oil. wOOt! 30 weight oil just doesn't sound idea to me with the way I drive, which is what that 0W-40 becomes for a lengthy period from the way it sounds. I just don't know. I'm not using 5W-40 mobil 1 because I have already purchaced 30 quarts of OW-40. Just kinda thinking I'd use some 15W-50 along with it. It's kind of a "Yes or No" at this point. [ June 01, 2004, 05:39 AM: Message edited by: rekced ]
 
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40,706
Location
Great Lakes
quote:
Originally posted by rekced: When I say drive hard, I mean 95 degree days in the summer with the AC on and redlining every gear with an APR chip.
I've done this kind of driving in the past (GIAC chip) in similar weather, with 0w-30 and 5w-30 synthetic oils. Oil temp remained in the 210-215F range, no matter how hard I pushed it.
quote:
I always figured the oil would sheer down in no time because of all the viscosity improvers.
Yes, the M1 0w-40 shears down a little bit, but it doesn't mean it's unable to do its job anymore. All oils shear or thicken a little during the normal course of their life inside an engine.
quote:
30 weight oil just doesn't sound idea to me with the way I drive,
I just don't get what is with people's fascination with very thick grades when the UOAs we've seen (chipped 1.8Ts as well) show that the thinner oils do the job just fine. At the same time, thinner oils flow quicker on cold startup, which is when most of the engine wear occurs anyway.
quote:
It's kind of a "Yes or No" at this point.
If I had to choose between these two, it would be 0w-40. [ June 01, 2004, 05:58 AM: Message edited by: Quattro Pete ]
 
Messages
404
Location
Palatine, IL
quote:
Originally posted by Quattro Pete:
quote:
Originally posted by therion: Am i murdering my 2003 Audi A4 1.8T with GC 0W-30??
Do a UOA and find out. [Wink] AFAIK, GC 0w-30 (Castrol SLX) is a factory fill for most audis these days. Starting next week, I'll be running SLX in my 1.8T as well. I also had good UOA results with M1 5w-30, so I see no evidence that this engine requires anything thicker than a 30-weight. [Cheers!]

I did an oil analysis with Amsoil s2k 0W-30, I was shocked by the lead [Eek!] so i switched to the thicker GC 0W-30 hopefully to solve my lead problems.  -
 
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40,706
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Great Lakes
therion, just curious, did you use any fuel additives/injector cleaners during that interval? That may account for the elevated lead. Even if not, I would not be too concerned - it's still a new engine. Wait and see how the GC does.
 
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46
Location
f
Try contacting a Mobil 1 technician, not the first person that answers the phone, but a real tech. See what they say about mixing. If you have the oil, go ahead with the mix. I doubt you will do any damage. When you change the oil do a UOA and see how the oil held up. Personally, I think it might be overkill, but what do I know.
 
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