Old specs vs new

[finis]

Question for the gallery. I have an 1985 Audi
Coupe GT Which calls for 15w-40 to 20w50 in summer months. The I-5 2.2L operates at high rpm
average is 35-4500rpm hiway. question is has the dino changed from '85 till now to the point where 10w30 is as shear resistant as the old 40 weight or are the about the same? Thanks in adavance....David

 

[Ugly3]

Stay with the recommended viscosity but stay on the low side of the range. Dinos are better today but the maker of the engine knows what is best.

 

[Sin City]

Motor oil has improved greatly since 1985. I would suggest using a 15W-40 motor oil that meets the API SL and CI-4 specifications. API SM motor oil will becomes available this fall and you should be able to use 10W-40 safely during the winter. I would only recommend 20W-50 (in warm weather) if you had hight oil consumption. I would not suggest using 10W-30 in your Audi.

[ August 10, 2004, 04:49 AM: Message edited by: Sin City ]

 

[Sin City]

quote:

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question is has the dino changed from '85 till now to the point where 10w30 is as shear resistant as the old 40 weight or are the about the same?

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I think a typical 10W-30 motor oil is still less shear stable than a typical 15W-40 motor oil. The most shear stable 10W-30 motor oils meet the API CI-4 rating (hard to find) and also some fully synthetic 10W-30 motor oils such as Mobil 1 are very shear stable.

[ August 10, 2004, 04:47 AM: Message edited by: Sin City ]

 

[kickster]

My 1990 VW also calls for same oil as your audi. recently I have switched to AMSOIL 5W40 and car runs fine. In fact all my start up valve noise has gone away. My oil consumption is zero after 4000KM. I dont think our old owner's manual makes any sense. They call for 5W30 for temps below -10 C. but you can use 10W30 for up to +15C
Thats 25 deg difference. What makes 10W30 so much better that it can stand to much higher temps! Both 5W30 and 10W30 should be able to protect your engine when hot. The viscosty may be slightly higher on 10w30 but it does not justify the jump from -10 to +15.

they also approve 15W40 for up to +35 C but 10W40 is only allowed up to +15 C.

As I said owner's manuals dont make any sense at all.

 

[Brian Reid]

quote:

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finis:
Question for the gallery. I have an 1985 Audi
Coupe GT Which calls for 15w-40 to 20w50 in summer months. The I-5 2.2L operates at high rpm
average is 35-4500rpm hiway. question is has the dino changed from '85 till now to the point where 10w30 is as shear resistant as the old 40 weight or are the about the same? Thanks in adavance....David

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Over the years I've owned a number of VW and Audi 4 in-line engined vehicles.

The only thing I ever found the factory-recommended viscosities provided was valve clatter on start-up in cold weather.

My last, a '90 VW, was run on 5W-30 Mobil 1 from its first oil change until I gave it to a charity with over 185k miles on it.

That included numerous high-speed runs of 80-90 mph in summer heat.

I wouldn't hesitate to move to a 10W-30 and see if the oil consumption holds up.

 

[finis]

I agee that owners manuals are confusing and this one is tops , which is why I sought experianced insight here. I have a 2001 F-150 4.6 with 89,000 miles on it, burned the manual, have run 10w30 since I drove it off the lot no leaks,no clatter runs like the day I bought it.
My Audi has no leaks , Does not burn any oil.I enjoy driving this car but high RPM motors like this do make me nervous and so the right lubrication is a MUST!
Thanks to all for your input. I think something in a Castrol 10w40 is in order. I am not sold on syn. Shear stability is and will always be my problem , anyone who buys 5 to 7k between oil changes is off there rocker...Thanks again!

David.