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Engine oil, which viscosity is best? [message #212339]

Wed, 26 June 2013 12:34

lw8000

Messages: 201
Registered: July 2012
Location: S.E. Michigan

Karma:

Senior Member

Hello,

We are getting close to changing the oil in our 77 Kingsley with the original Olds 403, around 64K original miles. I've been looking for the best synthetic oil for this engine, including winter grade (if possible) as we may end up starting it over the winter from time to time and temps can be down to 10-20 degrees Fahrenheit.

What is the ideal viscosity of synthetic oil to use in this engine? The original manual recommends:

SAE 30 @ 40 degrees F and up
20W-20 @ 10 to 80 degrees F
10W-30 @ -10 to 60 degrees F

I saw the thread from a couple years ago with a list of oil with high ZDDP content, and the viscosities ranged quite a bit. So far I'm seriously considering the 10W-30 Amsoil Z-Rod which has high ZDDP and is specifically designed for older engines:

http://www.amsoil.com/shop/by-product/motor-oil/gasoline/z-rod-10w-30-synthetic-motor-oil/?code=ZRTQT-EA

To my knowledge, 10W-30 runs as the same viscosity as SAE 30 once warm, so my thought was to stick to as close to the original recommendation as possible.

They also have the same oil as above but 20W-50:

http://www.amsoil.com/shop/by-product/motor-oil/gasoline/z-rod-20w-50-synthetic-motor-oil/?code=ZRFQT-EA

But maybe that is too thick.

Any suggestions on this? There are a lot of different viscosities and we want to make sure we use the correct one. We aren't sure which of synthetics run best in the 403.

Thank you!!

--
Chris

Chris S. - 77 Kingsley, 3.70 FD, mostly OEM - S.E. Michigan

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[Message index]

		Engine oil, which viscosity is best? By: lw8000 on Wed, 26 June 2013 12:34
		Re: Engine oil, which viscosity is best? By: Cadillackeeper on Wed, 26 June 2013 13:02
		Re: Engine oil, which viscosity is best? By: MIGUEL MENDEZ on Wed, 18 July 2018 14:59
		Re: Engine oil, which viscosity is best? By: Cadillackeeper on Wed, 26 June 2013 13:04
		Re: Engine oil, which viscosity is best? By: A Hamilto on Wed, 26 June 2013 13:07
		Re: [GMCnet] Engine oil, which viscosity is best? By: emerystora on Wed, 26 June 2013 13:06
		Re: [GMCnet] Engine oil, which viscosity is best? By: A Hamilto on Wed, 26 June 2013 13:16
		Re: [GMCnet] Engine oil, which viscosity is best? By: emerystora on Wed, 26 June 2013 16:42
		Re: [GMCnet] Engine oil, which viscosity is best? By: lw8000 on Wed, 26 June 2013 13:55
		Re: [GMCnet] Engine oil, which viscosity is best? By: emerystora on Wed, 26 June 2013 16:50
		Re: [GMCnet] Engine oil, which viscosity is best? By: lw8000 on Wed, 26 June 2013 21:50
		Re: [GMCnet] Engine oil, which viscosity is best? By: Michael Morton on Tue, 09 July 2013 16:09
		Re: Engine oil, which viscosity is best? By: jknezek on Wed, 26 June 2013 13:21
		Re: Engine oil, which viscosity is best? By: George B. on Wed, 26 June 2013 15:00
		Re: Engine oil, which viscosity is best? By: Michael Leipold on Wed, 26 June 2013 14:41
		Re: [GMCnet] Engine oil, which viscosity is best? By: sgltrac on Wed, 26 June 2013 15:44
		Re: [GMCnet] Engine oil, which viscosity is best? By: emerystora on Wed, 26 June 2013 16:54
		Re: Engine oil, which viscosity is best? By: Carl S. on Wed, 26 June 2013 16:20
		Re: Engine oil, which viscosity is best? By: JohnL455 on Wed, 26 June 2013 16:32
		Re: Engine oil, which viscosity is best? By: Cadillackeeper on Wed, 26 June 2013 17:33
		Re: [GMCnet] Engine oil, which viscosity is best? By: jhbridges on Wed, 26 June 2013 17:44
		Re: Engine oil, which viscosity is best? By: lw8000 on Sun, 07 July 2013 10:19
		Re: Engine oil, which viscosity is best? By: GMCNUSA on Tue, 09 July 2013 06:44
		Re: Engine oil, which viscosity is best? By: Ken Burton on Tue, 09 July 2013 07:32
		Re: Engine oil, which viscosity is best? By: Bob de Kruyff on Tue, 09 July 2013 00:07
		Re: Engine oil, which viscosity is best? By: Ken Burton on Tue, 09 July 2013 02:59
		Re: [GMCnet] Engine oil, which viscosity is best? By: jhbridges on Tue, 09 July 2013 07:47
		Re: [GMCnet] Engine oil, which viscosity is best? By: Matt Colie on Tue, 09 July 2013 08:48
		Re: [GMCnet] Engine oil, which viscosity is best? By: jhbridges on Tue, 09 July 2013 10:54
		Re: [GMCnet] Engine oil, which viscosity is best? By: Matt Colie on Tue, 09 July 2013 12:46
		Re: Engine oil, which viscosity is best? By: JohnL455 on Tue, 09 July 2013 19:41
		Re: Engine oil, which viscosity is best? By: JohnL455 on Tue, 09 July 2013 21:57
		Re: Engine oil, which viscosity is best? By: MIGUEL MENDEZ on Wed, 18 July 2018 15:41

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