Fluids, Refrigerant & Chemicals
DOT 3 vs DOT 4 vs DOT 5: The Numbers Are Not a Ladder
DOT 5 is silicone based and not compatible with the glycol fluids either side of it. DOT 5.1 is glycol based despite the number. That is the whole trap.
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Fluids, Refrigerant & Chemicals
Can You Mix Coolant Types? What OAT, HOAT and IAT Do
It depends on what and how much, and that cannot be judged from a description. Here is what the chemistries are and why the damage is slow and quiet.
Fluids, Refrigerant & Chemicals
Coolant Color Is Not a Spec: Reading the Actual One
Dye is not chemistry. The same color has covered different chemistries and the same chemistry has come in different colors. Here is what to read instead.
Fluids, Refrigerant & Chemicals
Oil Capacity vs Dipstick: Which One Is Actually Right?
A published capacity is an estimate for a nominal condition. The dipstick measures the engine in front of you, and the dipstick wins every time.
Fluids, Refrigerant & Chemicals
Full Synthetic vs Blend: Is the Label Even Regulated?
The words on the front of the bottle are far looser than buyers assume. The marks on the back are the part you can actually verify.
Fluids, Refrigerant & Chemicals
OEM Oil Approval vs Meets or Exceeds: Not the Same
An approval is a licence granted after testing and carries a checkable identifier. Meets-or-exceeds is the seller's own assertion. Here is how to tell.
Fluids, Refrigerant & Chemicals
ILSAC GF-6A vs GF-6B: Not Two Grades of One Thing
The A and B are not a quality ladder. They cover different viscosity territory and are deliberately not interchangeable, which is unusual in this field.
Fluids, Refrigerant & Chemicals
API SP vs SN: Manual Says One, Shelf Has the Other
Newer API S categories are generally intended to supersede older ones. Here is the principle, where it stops, and why your manual names an older letter.
Fluids, Refrigerant & Chemicals
What Does 5W-30 Mean? Two Grades, Not Two Units
The W is winter, not weight. Neither number is a measurement in any unit. They are grades from two separate tests, and that is the whole thing.
Fluids, Refrigerant & Chemicals
How to Read a Motor Oil Label: Which Marks Matter
Four independent systems plus marketing. Here is which markings are requirements your vehicle sets and which are words the seller chose.
Fluids, Refrigerant & Chemicals
What Fluids Does My Car Take? Finding Every Spec
Your owner's manual has a specifications section listing all six together. Here is what a real fluid specification looks like and why one word is not it.
Lug Pattern, Torque & Fasteners
Brake Caliper Bolt Torque: Where to Get the Real Number
Braking is a system where a professional is the right answer for most readers. Why a general torque chart is especially dangerous on these fasteners.