Why does my Kia Stonic overheat in stop‑and‑go traffic with AC on during hot Pakistani summers?

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Why does my Kia Stonic overheat in stop‑and‑go traffic with AC on during hot Pakistani summers?

Many Stonic owners report that when driving in heavy urban traffic for example in Lahore o r Karachi with the air conditioner running, the engine temperature climbs dangerously high o r the gauge moves into the red. The overheating is especially bad in summer heat above ~40‑45°C. What components are most likely failing o r under‑performing e.g. radiator fan, fan relay, thermostat, coolant type? Are cooling systems in Stonics suitably designed for high ambient temperature and heavy AC load in Pakistani cities?

Talha Kyanii asked on 20 Sep 2025 16:26:58 pm

1 Answer

25 views |

Gari Master - on 20 Sep 2025 16:28:54 pm

What is seen / known:

Owners in Lahore and other hot cities report the temperature gauge climbing into uncomfortable range when in traffic and AC is on, especially when ambient temperature is very high.
Gari.PK

On highways, the issue often becomes less severe. That suggests the airflow from motion helps cooling, but in slow traffic the cooling relies heavily on radiator fans and auxiliary cooling components which may be marginal under those stresses.
Gari.PK
+1

Likely causes:

Radiator fan o r fan relay weakness/failure: If the fan doesnt kick in at correct thresholds, o r the relay is weak, insufficient cooling in low airflow situations.
Gari.PK

Clogged radiator o r condenser: Dirt, dust, insects, and grime accumulate especially in urban/dusty climates and reduce airflow, reducing heat dissipation.
Gari.PK

Thermostat malfunction: A resistor o r mechanical thermostat may not open fully, delaying coolant flow until too late.
Gari.PK

Coolant quality / coolant dilution: Use of cheaper coolant, o r mixing with water improperly, lowers boiling point and efficiency. Also aged coolant loses heat carrying capacity.
Gari.PK
+1

What helps / what to check:

Verify if radiator fans operate properly in traffic listen/see.

Clean radiator fins / condenser pressure wash front when safe to remove dust o r debris.

Flush cooling system and use proper coolant mixture recommended by Kia.

Check thermostat, fan relay, temperature sensor.

Ensure engine oil level is good oil helps cooling in part.