Back to 1966 GMC 2500 Series
Help
1966 GMC 2500 SERIES
305 cu in (5.0L) V6•RWD•MANUAL•gas
Founding sponsor spot is openYour name on every procedure for this vehicle, permanently.Sponsor — $99 →
Repairs0Labor459Torque133Fluid8DTC0Battery1Maintenance0Recalls0
Fluid · Engine Oil

Engine Oil

for 1966 GMC 2500 Series 305 cu in (5.0L) V6 · RWD
Fluid Type
10W-30 or 10W-40 conventional
Spec: API SB/SC
Capacity
5qt
4.73 L
Drain & Refill
5 qt
4.73 L
Change Interval
3,000 mi
4,827 km

Notes

With filter. GMC 261 inline six (Pontiac-derived). Modern API SN or SP rated 10W-30 recommended.

Buy on Amazon
As an Amazon Associate and Autel/ANCEL partner, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.

Other fluid systems on this vehicle

🔌 Need this data in your app? It's all in the free API →
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Mechanic · 20+ years. Spot an error? Use the Help link above — a human reads every report.
Stuck on this repair? Take it to The Diag Desk — ask a master tech about this exact car → real human answer within 24h, never AI
Share:XRedditFBWhatsAppThreadsEmail
⚠ STILL BEHIND THE PAYWALL
The 1966 GMC 2500 Series repair data is incomplete because no one has sponsored it yet. For $99, we generate the full step-by-step procedures, then fact-check them with a second AI pass and your expert review. Your name on every procedure, permanently.
The same data would cost $169/mo from Mitchell1 or $30/year from ALLDATAdiy — and you'd be renting access, not freeing it. Sponsor once, free forever.
Sponsor the GMC 2500 Series — $99 →
Building an app?
Free API access to all this data — 10 requests/day, no card required.
Get an API key →
Run a shop?
Manage repairs, estimates, and customers with ShopBase — $249/mo, all features included.
Try ShopBase →