Automotive fluids
The patient shelf. Sealed oils, coolant and gear lube hold for 5 to 10 years, and their makers mostly decline to call it expiry at all — then there is brake fluid, which drinks water straight out of the air and gets about 6 months once the foil seal is broken.
Updated
Hung fastest-first — the tags at the top go off soonest
- Brake fluidSealed1–2 yearsSafety issue
- DEF (diesel exhaust fluid)Sealed1–3 years, by temperatureDegraded performance
- Starting fluidSealed2 yearsDegraded performance
- Bar and chain oilSealed4 yearsDegraded performance
- Gear oilSealed5 yearsDegraded performance
- Motor oilSealedAbout 5 yearsHarmless
- Power steering fluidSealed5 yearsDegraded performance
- Synthetic oilSealed5 yearsHarmless
- Transmission fluidSealed5 yearsDegraded performance
- AntifreezeSealed8–10 yearsDegraded performance
- Windshield washer fluidSealedDoesn't meaningfully expire sealedDegraded performance