EXPRESS E1 · BAY REFERENCE
FLUID SERVICE SPEC SHEET
Every fluid in a vehicle, the spec it needs, and the consequence of using the wrong one. Never trust "any 5W-30" or "universal ATF" — read the cap, read the door placard, read the owner\'s manual.
REFERENCE VISUAL
Fluid Spec
5 bay fluids · spec callouts · never-mix rules.
VISUAL FLUID DECODER
Match what you see at the cap or in the bottle to the spec. Color is the first clue, but always confirm against the OEM call.
MOTOR OIL · GRADE COLOR (AMBER FAMILY)
0W-20
5W-20
5W-30
10W-30
5W-40
15W-40
COOLANT · CHEMISTRY BY COLOR
IAT · GREEN
Old · pre-1996
OAT · ORANGE
GM Dex-Cool, VW
HOAT · YELLOW
Ford, Chrysler, MB
POAT · PINK
Toyota, Honda, KIA
⚠ NEVER MIX
Coolant types chemically react. Brake fluid types (DOT 3/4 vs DOT 5) cannot mix. ATF spec (Dexron, Mercon, ATF+4, WS, CVT) is platform-specific. Wrong fluid = ruined system. Always confirm.
MOTOR OIL
| Grade | Use case | Notes |
|---|---|---|
| 0W-20 | Modern small engines, hybrids, turbo small-displacement | Most common factory fill 2015+. Fuel economy oil. |
| 5W-20 | Light-duty cars, trucks 2005+ | Older spec — common owner\'s manual call. |
| 5W-30 | Most cars/light trucks pre-2015, many GM/Ford/Stellantis | The universal-ish grade. Default if uncertain. |
| 10W-30 | Older engines, high-mileage | Thicker base, more cushion for worn engines. |
| 5W-40 / 0W-40 | European cars, performance, turbo diesels | Mercedes, BMW, VW often spec this. |
| 15W-40 | Heavy-duty diesel (Cummins, Powerstroke, Duramax) | Always confirm with diesel oil cap. |
Conventional vs Synthetic vs Synthetic-blend: Modern engines with extended drain intervals require full synthetic. Don\'t downgrade. Synthetic blend = budget option; conventional only on older engines per manual.
COOLANT / ANTIFREEZE
| Type | Color (usually) | Compatible with | Service interval |
|---|---|---|---|
| IAT (Inorganic Acid Tech) | Green | Most pre-1996 vehicles | 2 yr / 30K mi |
| OAT (Organic Acid Tech) | Orange, red, pink | Modern GM, VW, some Asian | 5 yr / 150K mi |
| HOAT (Hybrid OAT) | Yellow, pink, blue | Ford, Chrysler, Mercedes, some Asian | 5 yr / 100K mi |
| POAT (Phosphate OAT) | Pink, blue, purple | Toyota, Honda, Nissan, Hyundai/Kia | 10 yr / 120K mi (first fill) |
DO NOT MIX coolant types. The additive packages chemically react and form gel that clogs heater cores and water passages. Always match what\'s in the system — flush completely if changing types.
Always mix 50/50 with distilled water (or use pre-mix).
Always mix 50/50 with distilled water (or use pre-mix).
AUTOMATIC TRANSMISSION FLUID (ATF)
| Spec | Vehicles | Notes |
|---|---|---|
| Dexron VI | GM 2006+, many Asian rebrands | Backwards compatible with Dexron III applications |
| Mercon V / LV / ULV | Ford-specific by year/model | NOT cross-compatible — check application |
| ATF+4 (MS-9602) | Chrysler, Jeep, Ram | Required for Mopar transmissions |
| SP-IV / SP-III | Hyundai, Kia, Mitsubishi | SP-IV for newer 6-speed and up |
| ATF DW-1 / Z-1 | Honda | Honda is famously fluid-specific — DO NOT substitute |
| Toyota WS | Toyota 2006+ | "World Standard" — proprietary, OEM only |
| CVT-specific | Continuously Variable Transmissions (any brand) | NEVER use regular ATF in a CVT — destroys belt/chain |
CVT WARNING: CVTs need their specific CVT fluid. "Multi-vehicle" ATF will destroy a CVT in days. Always confirm transmission type before fluid service.
BRAKE FLUID
| DOT | Type | Boiling point (dry / wet) | Use |
|---|---|---|---|
| DOT 3 | Glycol-based | 401°F / 284°F | Most standard daily-driver vehicles. Common. |
| DOT 4 | Glycol-based | 446°F / 311°F | European, ABS, performance vehicles. Backwards compatible with DOT 3. |
| DOT 4 LV / 4.1 / Super DOT 4 | Low-viscosity glycol | 500°F / 356°F | Modern European stability control systems. Faster ABS response. |
| DOT 5 | Silicone-based | 500°F / 356°F | Military, classic cars. NEVER mix with glycol-based fluids. |
| DOT 5.1 | Glycol-based (NOT silicone) | 500°F / 356°F | High-performance. Compatible with DOT 3 / 4. |
Replace every 2 years. Glycol-based brake fluids absorb moisture from air — over 3% moisture lowers boiling point dramatically, leading to brake fade. Test with moisture tester before topping off.
OTHER FLUIDS
| Fluid | Spec / Type | Notes |
|---|---|---|
| Power steering fluid | OE-specific (PSF, ATF, or proprietary) | NEVER guess. Honda has its own, Toyota uses ATF, GM has its own. Check cap. |
| Manual transmission fluid | GL-4 or GL-5, weight per spec | GL-5 can damage brass synchros in some MTs. Match exactly. |
| Differential fluid | Synthetic 75W-90 typical | Limited-slip diff needs LS additive. Check. |
| Transfer case fluid | OE-specific (ATF, gear oil, or proprietary) | Many specify their own — read the manual. |
| Washer fluid | Methanol-based for freeze protection | Concentrate or pre-mixed. Cold-climate freezes basic water. |
| DEF (diesel only) | 32.5% urea, ISO 22241 / API DEF | Never use water or off-brand. Damages SCR catalyst. |
PRO MOVE
FLUID SAFETY CHECKLIST
Before any fluid service: (1) verify what\'s currently in the system (cap label, dipstick color), (2) verify what the OEM specifies (manual, owner\'s portal, AllData), (3) match them. If mismatch, drain entirely — never just top off. (4) Use OE or OE-equivalent on warranty vehicles; aftermarket is fine for out-of-warranty if it meets spec. (5) Wrong fluid is a comeback waiting to happen. Take the extra 2 minutes.