Factory lubricant standards (SAE, API, ACEA), tire pressure and sizing tolerances, scheduled service intervals, and symptom diagnostics.
| Engine Oil Standards | SAE J300 · API SP · ILSAC GF-6A/6B · ACEA A3/B4, C3, C5, C6 |
|---|---|
| Brake Fluid Standards | FMVSS 116 / ISO 4925 DOT 3, DOT 4, DOT 4 LV (Class 6), DOT 5.1 |
| Coolant Formulations | ASTM D3306 · IAT, OAT (G12+), HOAT (G11), Lobrid Si-OAT (G12++/G13) |
| Tire & Wheel Standards | ETRTO / ISO 4000-1 · ±1.5% Ideal Rolling Diameter Tolerance |
Current Focus · Service & Diagnostics
Check SAE J300 viscosity grades (0W-20 vs 5W-30), verify tire rolling diameter tolerances, and decode OBD-II fuel trims before a long drive.
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01 · SAE J300 / API SP / ACEA
How to read viscosity grades, OEM approvals, and HTHS shear stability before your next oil change.
Compare SAE 0W-16, 0W-20, 5W-30, and 5W-40 grades across API SP, ILSAC GF-6A, ACEA C3/C5, VW 504.00/508.00, BMW LL-04, and MB 229.52.
maintenance · 8 min
How to match cold-cranking viscosity (0W/5W), HTHS shear stability, Low-SAPS ash limits (ACEA C2/C3/C5), and LSPI protection (API SP) to your engine.
maintenance · 9 min
Preventive replacement intervals for engine oil, DOT 4 brake fluid, ATF/CVT/DCT transmission fluid, coolant, spark plugs, and timing belts.
tires · 7 min
Complete engineering reference for ISO metric tire sizing (e.g., 225/45 R17 94W XL), DOT manufacture week/year, and winter 3PMSF homologation.
buying · 10 min
How to verify structural integrity with a coating thickness gauge (µm), detect recently cleared fault codes via OBD-II Mode $01/$06, and test powertrain health.
diagnostics · 8 min
Using Short-Term (STFT) and Long-Term Fuel Trim (LTFT) percentages at idle vs 2,500 RPM to pinpoint air/fuel ratio faults without guessing parts.
maintenance · 7 min
Open-circuit resting voltage vs State of Charge (SoC), minimum cranking voltage drop, smart alternator charging ranges, and AGM/EFB replacement rules.
maintenance · 9 min
Engineering differences between planetary automatics, steel push-belt CVTs, and wet/dry dual-clutch gearboxes — plus exact fluid service intervals.
maintenance · 7 min
Why coolant dye color is not a specification, how silicate vs phosphate corrosion inhibitors protect aluminum blocks, and refractometer freeze-point testing.
buying · 8 min
How to decode all 17 characters of a Vehicle Identification Number (WMI, VDS, VIS), verify physical stamping zones, and check open safety recalls.
tools · 7 min
Why WLTP laboratory numbers differ from US EPA 5-cycle tests, exact conversion formulas between L/100 km and MPG, and how speed affects drag.
maintenance · 7 min
Pre-departure inspection points 48 hours before a long highway journey: full-load tire pressures, spare tire inflation, brake pad thickness, and mandatory road safety gear.
emergency · 6 min
Step-by-step roadside survival and documentation protocol: hazard lights, high-visibility vests, warning triangle distance, emergency call coordinates, and photo evidence.
02 · Diagnostics & Pre-Trip Safety
Verify tire tolerances, fuel consumption, and OBD-II fault codes before winter or highway travel.
Use our browser calculators to compare tire sizes, convert metric and imperial units, and decode Check Engine fault codes.