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Oil recommendations? [message #347646] Tue, 10 September 2019 16:38 Go to next message
agoogol is currently offline  agoogol   United States
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Going to do my first oil change on my 77 GMC with the 403....what does everyone recommend nowadays for an oil to use? 62k miles, probably won't drive too much for the next year or so, just around town/shorter trips to the mountains etc until I invest in enough to make her more reliable.

Seems like all the articles are old on t his subject, so I thought I would throw it out there!



Kevin Carter 1977 Kingsley - 403 c.i. Centennial CO
Re: Oil recommendations? [message #347652 is a reply to message #347646] Tue, 10 September 2019 19:45 Go to previous messageGo to next message
jhbridges is currently offline  jhbridges   United States
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<popping popcorn>

--johnny


Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. I forgive them all, save those who hurt the dogs. They must answer to me in hell
Re: Oil recommendations? [message #347654 is a reply to message #347646] Tue, 10 September 2019 20:26 Go to previous messageGo to next message
agoogol is currently offline  agoogol   United States
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Synthetic 10 - 40 is what I am coming to and then be able to use it in the Onan as well. Of course that's provided I get the Onan running. Doesn't really make or break anything I'm sure.

Kevin Carter 1977 Kingsley - 403 c.i. Centennial CO
Re: Oil recommendations? [message #347660 is a reply to message #347646] Wed, 11 September 2019 07:50 Go to previous messageGo to next message
JohnL455 is currently offline  JohnL455   United States
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I only use Shell Rotella T6 5W-40 full synthetic. I think the 5 cold weight is beneficial in vehicles that sit long periods as these do to flow to parts quickly at startup.

John Lebetski
Woodstock, IL
77 Eleganza II
Re: Oil recommendations? [message #347662 is a reply to message #347646] Wed, 11 September 2019 08:21 Go to previous messageGo to next message
Russell K. is currently offline  Russell K.   United States
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Kevin,
The oil question will get many different answers. Everyone has their favorite oil. More important than brand, is frequency. Change the oil often, and get your used oil analyzed at Blackstone Laboratories to monitor engine wear and potential problems. Oil is cheap compared to the cost of replacing an engine.

Here is a good article from Blackstone about which oil is best.
https://www.blackstone-labs.com/wp-content/uploads/2018/09/Aug-17-ENG.pdf

BTW, I use Valvoline VR1 racing motor oil 20W-50 in my high mileage '78 403, and change it around 2k-3k miles. Some may chime in as to why its the wrong oil for this application. That's OK. We all need to be willing to learn from the experience of others.

Here is a copy of the oil analysis from my most recent oil change.
http://www.gmcmhphotos.com/photos/data/7215/Oil_Analysis_HARRYS_403-190420.pdf

Welcome to the group. We all love our GMC's.

Safe Travels,
Russell


1978 Eleganza II, Dunedin, Florida

[Updated on: Wed, 11 September 2019 08:45]

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Re: Oil recommendations? [message #347673 is a reply to message #347662] Wed, 11 September 2019 10:17 Go to previous messageGo to next message
mghamms is currently offline  mghamms   United States
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I use Mobil 1 15w50. But most anything will work fine.
A ways change the filter.Use whatever floats you boat.


1977 Kingsley 455 as stock as it gets except lots of Ragusa parts
Re: [GMCnet] Oil recommendations? [message #347676 is a reply to message #347673] Wed, 11 September 2019 10:57 Go to previous message
jimk is currently offline  jimk   United States
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What is also important is the Air Filter and how it seals to prevent dirt
from being pulled through the seals and gaskets.
I am a Certified Air Filter Specialist so I sort of know what particulars
can do for different application.
Washable filters are never worth putting on.

On Wed, Sep 11, 2019 at 8:18 AM Mike Hamm via Gmclist <
gmclist@list.gmcnet.org> wrote:

> I use Mobil 1 15w50. But most anything will work fine.
> A ways change the filter.Use whatever floats you boat.
> --
> 1977 Kingsley 455 as stock as it gets except lots of Ragusa parts
>
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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