Mountains: how not to burn the brakes descending or cook the engine climbing

A mountain road loads a car unlike a motorway or a town: two opposite regimes in succession, each exposing its own weakness. Climbing means overheating, descending means brakes.

Descending: the main mistake

Resting a foot on the brake all the way down is the most common and most dangerous error.

What happens: brakes convert energy into heat. Under continuous braking the heat cannot escape. Then:

1. The pads heat up and lose friction — stopping distances grow.
2. Brake fluid in the calipers boils — the pedal sinks. Especially fast if the fluid is old and moisture-laden; covered in the brake fluid article.
3. There are effectively no brakes, and the road continues.

Engine braking

The right way: select a lower gear and let the engine restrain the car. Use the brakes in short, firm applications rather than constant pressure.

The logic: a short application sheds speed, then the pause lets airflow cool the brakes. Constant light pressure heats them without shedding speed.

On an automatic — manual mode or L. The same applies to most modern gearboxes.

On an electric car or hybrid — regeneration does this naturally, but with a full battery it is limited and the friction brakes take over again. Worth remembering precisely on a long descent.

Climbing: overheating

The load is constant and high while speed is low — so there is little airflow.

What heats up: the engine, an automatic gearbox, and the brakes during frequent stops.

What to do as the temperature climbs:

1. Switch off the air conditioning — that removes load immediately.
2. Put the heater on full — the matrix acts as an extra radiator.
3. Stop somewhere safe and let it idle — switching off at once is not ideal, circulation helps.
4. Do not open the cap on a hot system.

The general case is covered in the overheating article.

Tyre pressures and altitude

Atmospheric pressure falls with altitude, so relative tyre pressure rises slightly. At the same time the tyres heat up from hard work.

In practice: check pressures cold in the morning and do not let hot tyres down “to specification” — the classic mistake that leaves them under-inflated.

What to check before the trip

1. Brake fluid — age and water content. The top item on the list.
2. Pad thickness and disc condition.
3. The cooling system — level, coolant condition, fan.
4. Oil — level and freshness.
5. Tyres — pressure and condition.
6. Read the codes — so you do not discover a problem on a hairpin.

What to watch on the road

Coolant temperature — the real one, not the needle; on a climb it is the key parameter.

Transmission temperature on an automatic — it heats as much as the engine.

Voltage — with the fan running constantly the alternator load rises.

In short

• Constant brake pressure on a descent is the main and most dangerous mistake.
• Brake short and firm, with pauses to cool.
• A lower gear does the main work instead of the brakes.
• Overheating on a climb: air conditioning off, heater to maximum.
• Brake fluid is item number one in preparing for mountains.

Download the app — engine and transmission temperatures are read with an ELM327 adapter over Bluetooth SPP on Android, on the road.