Freeze-thaw at maximum amplitude
A pothole is water that got into a crack, froze, expanded, broke the surface apart, then thawed and let traffic finish the job. How bad it gets depends on how far the temperature swings and how often.
The Twin Cities swing further than almost anywhere: deep sub-zero winters, and a spring that repeatedly crosses freezing within a single day. That combination is what turns a crack into a crater between February and April.
Spring here is genuinely a season with a name attached, and the damage from one hard strike reaches further than the wheel:
- The wheel bearing. Races brinelled by the impact. Silent that week, rumbling months later.
- Steering geometry. Camber and toe move when a control arm or strut takes a hit — a pull, a wheel that tramlines, a tyre wearing one shoulder.
- Control arm bushings. Torn under shock loading rather than worn out. Clunk over joints, vague steering.
- The strut. A bent rod binds; a knock on rebound and a car that never settles after a crest.
- The rim. Bent against the edge of a hole, holding air, looking fine, and producing a vibration nothing balances out.
Eight months of treatment
The winter here is long and the treatment season with it. That gives brine more months to reach everything that cannot dry out: brake lines corroding from the outside, caliper slides seizing, wheel speed sensors bonding into aluminium knuckles, and every underbody fastener becoming a question.
So the pothole damage above happens to a car whose fasteners are already fighting back — which is exactly why the buying rule here is the complete assembly rather than the component. The removal is the expensive half of the job.
Sub-zero starts
At twenty below, the oil barely flows and the battery is at a fraction of its rated current while the starter has the thickest oil it will ever turn. Demand rises exactly as supply falls, and those first seconds before oil pressure reaches the top of the engine are the highest-wear moments in its life.
A synthetic oil at the correct low-temperature grade flows dramatically better cold, and this is the climate where that difference is worth paying for.
The damage that kills a battery happens in summer heat; cold only reveals it. Replace on age, before winter, rather than on failure in a car park in January.
Short trips, and the skyways
The downtown skyway system means a great many people park once and walk, and the trip in is often short.
A short journey never brings an engine to full operating temperature, so the oil does not get hot enough to evaporate the water and fuel condensing into it. Time-based oil intervals exist for exactly this pattern, and the odometer will argue against them.
The battery has the same problem from the other side: starting takes a great deal out and a short cold trip with lights, heater and defrost running does not put it back.
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