Click on image for the lowdown. 
====
| | | Forums66 Topics128,212 Posts1,057,465 Members48,471 | | Most Online14,466 Apr 26th, 2026 | | AD Chevy Trucks Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
| | THANKS!
For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down with Ads! Again, thanks! | | | | Joined: May 2008 Posts: 210 Shop Shark | | Shop Shark Joined: May 2008 Posts: 210 | What grade of oil should I use in my 235 that has not run for 20 years? Should I go thick or thin? How about Lucas Oil Stabilizer when I first fill it up? | | | | | Joined: Jul 2004 Posts: 5,708 'Bolter | | 'Bolter Joined: Jul 2004 Posts: 5,708 | 46 HalfTon,
I would use some generic 30wt detergent. Put a few hours on the engine and change oil again, using the same stuff. I was stay away from any additive.
Stuart | | | | | Joined: Jun 2004 Posts: 8,597 Riding in the Passing Lane | | Riding in the Passing Lane Joined: Jun 2004 Posts: 8,597 | You will get many opinions on this subject. I would use a good brand of 10/40. They say money can't buy happiness. It can buy old Chevy trucks though. Same thing. 1972 Chevy c10 Cheyenne SuperIn the Gallery Forum | | | | | Joined: Dec 2003 Posts: 2,953 'Bolter | | 'Bolter Joined: Dec 2003 Posts: 2,953 | I use 10-30 but my knowledgeable mechanic says I should put in 10-40 from now on. | | | | | Joined: Dec 2006 Posts: 1,154 Shop Shark | | Shop Shark Joined: Dec 2006 Posts: 1,154 | 10-30 Vavoline racing oil with 4oz. of ZDDP added. T/C Steve | | | | | Joined: Jan 2007 Posts: 615 Shop Shark | | Shop Shark Joined: Jan 2007 Posts: 615 | I've used 20-50 with no problems..but I must admit I had no real reason for doing so..other than wanting to keep the oil pressure as high as I could..no science to my process..
Keith | | | | | Joined: Dec 2006 Posts: 1,154 Shop Shark | | Shop Shark Joined: Dec 2006 Posts: 1,154 | Kieth do you get more pressure but less flow because of the viscosity? My uncle says that 10-30 makes them easier to start cold and better lubrication off the mark. He also says straight degertent 30 weight is all you need at least in our part of the country..... But I still add ZDDP makes him spit rocks when I do! Steve | | | | | Joined: May 2006 Posts: 8,351 'Bolter | | 'Bolter Joined: May 2006 Posts: 8,351 | Straight 30 is just fine for these old engines. Adding ZDDP is unnessesary, it's only needed for break in.
Bill Burmeister | | | | | Joined: Apr 2008 Posts: 136 Wrench Fetcher | | Wrench Fetcher Joined: Apr 2008 Posts: 136 | I like 15/40 in old motors | | | | | Joined: Dec 2006 Posts: 1,154 Shop Shark | | Shop Shark Joined: Dec 2006 Posts: 1,154 | Bill you (and my uncle) are of course right but I figure it can't hurt as I have no idea how bad/good the PO (when not drunk) treated this engine/truck. I have run across many a weird thing on this truck. In fact I just installed two adjustable bar supports across the radiator near the tank front and aft. The PO butchered the radiator support for the longer 55/235 he did not understand that the radiator cross member holds the fenders from sagging and stops the radiator from splitting apart. Chevy had a lot of problems on the early models and thus the X bracing and the 54's had the top channel. The ZDDP its a feel good thing that makes no sense but then again hobbies never make much sense, that's why they are hobbies I guess. :>) T/C Steve
| | | | | Joined: May 2008 Posts: 114 Shop Shark | | Shop Shark Joined: May 2008 Posts: 114 | After checking the 283 in my '57 chev. for sludge build-up I changed the oil filter to a spin on and started using Mobil 1 synthetic 10w30. I've used this oil in my 'new' vehicles and have never had any problems. Its important for the motors interior to be clean otherwise the high detergent synthetics can break loose inside sludge and gunk up the oil pump pickup. Having one oil type for all my vehicles simplifies life. All of the other oils mentioned above will certainly work well, just follow routine servicing schedules. JAMES | | | | | Joined: Apr 2008 Posts: 9 New Guy | | New Guy Joined: Apr 2008 Posts: 9 | I like 15/40 in old motors i agree,, till its down to freezing them i use 5-30 | | |
| |