Basic Vehicle Fluids

Overview

Fluids are your vehicle’s blood and cooling system. Use the correct type, check levels safely, and top off thoughtfully. When in doubt, consult the owner’s manual or the under‑hood labels.

Engine Oil Types

Viscosity and specification matter.

• Viscosity: 0W‑20, 5W‑30, etc. Match manual/hood sticker.
• Specs: Look for API/ACEA approvals required by your engine.
• Top‑off: Check dipstick on level ground with engine off and cool; add small amounts; avoid overfill.

Coolant Types

Not all coolants mix. Use the specified type.

• Types: OAT/HOAT/IAT; colors vary by brand—don’t trust color alone.
• Overflow tank: Check level cold; add premix of the correct type.
• Radiator cap: Never open hot; use a rag; open slowly when cool.

Brake Fluid

Critical for stopping; absorbs water over time.

• Types: DOT 3/4/5.1 are glycol‑based and mixable; DOT 5 (silicone) is not—don’t mix with others.
• Reservoir: Keep clean; avoid contaminating with oil/grease; cap quickly.

Power Steering Fluid

Types vary; some use ATF. Check manual/cap label. Check level with engine off (or as manual states).

Washer Fluid

Use seasonal blends (de‑icer in winter). Fill to near top; avoid plain water in freezing climates.

Top-Off Cautions

Avoid cross‑contamination and burns.

• Identify caps clearly; read labels; keep funnels separate for oil/coolant.
• Let hot engines cool before opening pressurized systems.

☑️ Checklist — Fluids Quick Guide

• Oil: correct viscosity/spec; add small amounts; recheck dipstick
• Coolant: correct type; fill overflow; never open hot radiator
• Brake: correct DOT; keep clean; don’t spill on paint
• Power steering: correct fluid (may be ATF); check as directed
• Washer: seasonal blend; keep topped

Examples

• Low oil light: Park level; wait 5 minutes; check dipstick; add 0.5 L of specified oil; recheck; investigate leak/consumption soon.
• Overheat after climb: Cool down; top overflow with correct premix; do not open hot cap; plan coolant system check.

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Key Takeaways

• Use the right fluid type; avoid mixing unknown coolants and DOT 5 with others.
• Check levels safely; hot systems can injure.
• Keep separate funnels/containers to avoid contamination.

Scenario

🧭 Scenario (Coolant mixup averted): Steam after a climb; you’re low.
🔍 Decisions: Open hot cap vs overflow; type check; limp vs stop.
✅ Outcome: You cool, top the overflow with correct mix, avoid opening the cap hot, and get service later.
🧠 Lessons: Don’t mix unknown coolants; never open hot
🏋️ Drill: Find your coolant spec on the cap/manual.