Oil type for a stock 41 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Jacfourteen · 04-01-2010, 05:57 PM

I need to do an oil change on my wife's 41 gmc before I take it to a show on may 8th and was wondering what would be best for the stock I6. Any help is greatly appreciated.

**Dan in Pasadena** · 04-01-2010, 11:20 PM

I'm no expert on the old engines but if it were mine I'd use a straight 30 wt. Like Castrol Heavy Duty.

Jacfourteen · 04-02-2010, 01:18 AM

That was my thought, but I'm not sure if I should use detergent or non-detergent. Any thoughts?

clinebarger · 04-02-2010, 11:17 AM

If it does not have a oil filter I whould use non-detergent.

Jacfourteen · 04-03-2010, 03:42 AM

Quote:

Originally Posted by clinebarger

If it does not have a oil filter I whould use non-detergent.

thanks for the heads up. I don't even know if this thing has a filter or not, I guess that's on the list for the to do list before the show.

K-TEN · 04-05-2010, 03:33 PM

The oil filter will be pretty obvious. If it's a Chevy it's bracketed onto to the intake manifold. If it's a GMC, it will be on the pass. side mid-block at the front. I would DEFINITELY NOT use detergent motor oil on an un-rebuilt vintage engine. Detergent oil will start to clean up the sludge and then clog your internal oil passages with that same sludge. Main bearings will be the first target. 30 or 40 weight is correct depending upon your location. Have fun at the show.

**special-K** · 04-06-2010, 07:33 AM

I agree on the straight weight.I`m thinking 40w for warm weather especially if the motor has miles on it.

Jacfourteen · 04-07-2010, 12:03 AM

Thanks for all the replies. The motor was rebuilt about 10-15 years ago, and has prolly only 500-600 miles on it. It was restored by my wife's grandpa and he passed away 8 years ago, since then I've only driven it twice. I started working on it today to get it in shape for the show. I charged the battery and fired it up, I must have junk in the needle valve because it is blowing black smoke and the carb is overflowing. I pulled a wheel cyl and took it to the local napa and they said that it is from a 53 chevy, so I ordered 2 complete cyl and 2 rebuild kits. So now I gotta get the brakes back together and move it from the small garage to the big garage then pull the carb, change the oil, and start cleaning.

K-TEN · 04-07-2010, 07:14 AM

Then in that case use the latest and greatest multiweight detergent oil you can buy. Even synthetic oil might keep new sludge to a minimum.
And you should probably do all 4 brakes completely over, not just 2.

**Dan in Pasadena** · 04-07-2010, 11:08 AM

Personally, I'd still use a straight 30 wt. in a 60+ year old engine. But I agree with K-Ten that you MUST do all four brakes.

Grandpa went to more modern Bendix brakes instead of searching for the original Huck brake parts/kits. These days you can buy parts for those from Chev's of the 40's and others but 10-15 years ago (or more) I doubt it was as easy...and I doubt if Grandpa was as internet saavy as a Grandpa (like me!) is today.

04-01-2010, 05:57 PM	#1
Jacfourteen Big Red - Now its a SWB! Join Date: Jun 2009 Location: Oroville, Ca Posts: 1,624	Oil type for a stock 41 I need to do an oil change on my wife's 41 gmc before I take it to a show on may 8th and was wondering what would be best for the stock I6. Any help is greatly appreciated. __________________ 68 3/4 ton (Project)-350 Small Block, .030 over, 10:1 comp, 3998993 heads, C3BX edelbrock intake, comp cams XE268, Holley 670 SA, long tube headers, dual flow 40's, E-fan, Alum rad, currently under the knife getting shortened and bagged build thread 41 3/4 ton (wife's)-flatbed, fully restored to original 01 Tahoe LT 4WD (my daily driver)-Magnaflow Muffler, Rollin on 22's 02 Ford Mustang Convertable (Wife's Car)-Flowmaster 50, Clear corners, Intake, sittin on 18's

04-01-2010, 11:20 PM	#2
Dan in Pasadena Senior Member Join Date: Nov 2008 Location: Glendora, CA Posts: 6,331	Re: Oil type for a stock 41 I'm no expert on the old engines but if it were mine I'd use a straight 30 wt. Like Castrol Heavy Duty.

04-02-2010, 01:18 AM	#3
Jacfourteen Big Red - Now its a SWB! Join Date: Jun 2009 Location: Oroville, Ca Posts: 1,624	Re: Oil type for a stock 41 That was my thought, but I'm not sure if I should use detergent or non-detergent. Any thoughts? __________________ 68 3/4 ton (Project)-350 Small Block, .030 over, 10:1 comp, 3998993 heads, C3BX edelbrock intake, comp cams XE268, Holley 670 SA, long tube headers, dual flow 40's, E-fan, Alum rad, currently under the knife getting shortened and bagged build thread 41 3/4 ton (wife's)-flatbed, fully restored to original 01 Tahoe LT 4WD (my daily driver)-Magnaflow Muffler, Rollin on 22's 02 Ford Mustang Convertable (Wife's Car)-Flowmaster 50, Clear corners, Intake, sittin on 18's

04-02-2010, 11:17 AM	#4
clinebarger Senior Member Join Date: May 2009 Location: Fort Worth, TX Posts: 6,370	Re: Oil type for a stock 41 If it does not have a oil filter I whould use non-detergent.

04-05-2010, 03:33 PM	#6
K-TEN Registered User Join Date: Feb 2010 Location: Epsom, NH Posts: 114	Re: Oil type for a stock 41 The oil filter will be pretty obvious. If it's a Chevy it's bracketed onto to the intake manifold. If it's a GMC, it will be on the pass. side mid-block at the front. I would DEFINITELY NOT use detergent motor oil on an un-rebuilt vintage engine. Detergent oil will start to clean up the sludge and then clog your internal oil passages with that same sludge. Main bearings will be the first target. 30 or 40 weight is correct depending upon your location. Have fun at the show.

04-06-2010, 07:33 AM	#7
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,863	Re: Oil type for a stock 41 I agree on the straight weight.I`m thinking 40w for warm weather especially if the motor has miles on it. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

04-07-2010, 12:03 AM	#8
Jacfourteen Big Red - Now its a SWB! Join Date: Jun 2009 Location: Oroville, Ca Posts: 1,624	Re: Oil type for a stock 41 Thanks for all the replies. The motor was rebuilt about 10-15 years ago, and has prolly only 500-600 miles on it. It was restored by my wife's grandpa and he passed away 8 years ago, since then I've only driven it twice. I started working on it today to get it in shape for the show. I charged the battery and fired it up, I must have junk in the needle valve because it is blowing black smoke and the carb is overflowing. I pulled a wheel cyl and took it to the local napa and they said that it is from a 53 chevy, so I ordered 2 complete cyl and 2 rebuild kits. So now I gotta get the brakes back together and move it from the small garage to the big garage then pull the carb, change the oil, and start cleaning. __________________ 68 3/4 ton (Project)-350 Small Block, .030 over, 10:1 comp, 3998993 heads, C3BX edelbrock intake, comp cams XE268, Holley 670 SA, long tube headers, dual flow 40's, E-fan, Alum rad, currently under the knife getting shortened and bagged build thread 41 3/4 ton (wife's)-flatbed, fully restored to original 01 Tahoe LT 4WD (my daily driver)-Magnaflow Muffler, Rollin on 22's 02 Ford Mustang Convertable (Wife's Car)-Flowmaster 50, Clear corners, Intake, sittin on 18's

04-07-2010, 07:14 AM	#9
K-TEN Registered User Join Date: Feb 2010 Location: Epsom, NH Posts: 114	Re: Oil type for a stock 41 Then in that case use the latest and greatest multiweight detergent oil you can buy. Even synthetic oil might keep new sludge to a minimum. And you should probably do all 4 brakes completely over, not just 2.

04-07-2010, 11:08 AM	#10
Dan in Pasadena Senior Member Join Date: Nov 2008 Location: Glendora, CA Posts: 6,331	Re: Oil type for a stock 41 Personally, I'd still use a straight 30 wt. in a 60+ year old engine. But I agree with K-Ten that you MUST do all four brakes. Grandpa went to more modern Bendix brakes instead of searching for the original Huck brake parts/kits. These days you can buy parts for those from Chev's of the 40's and others but 10-15 years ago (or more) I doubt it was as easy...and I doubt if Grandpa was as internet saavy as a Grandpa (like me!) is today.



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