Quick Answer
A 2020 Bentley Bentayga W12 overheated exclusively in slow traffic during summer. The dealer quoted AED 45,000 for radiator, water pump, and thermostat replacement. Root cause: a failed auxi
The Bentayga's 6.0-litre twin-turbo W12 produces enough heat to warm a small building. At highway speed, airflow through the radiator pack handles this heat comfortably. In Dubai summer traffic, at 5 km/h, the cooling system depends entirely on electric fans to push air through the radiator.
When those fans aren't working at full capacity, the temperature gauge climbs. And in a W12 Bentayga, overheating is a AED 80,000+ engine risk.
Symptoms:
Owner's experience: Three incidents over one summer. Each time, the temperature warning appeared after 15-20 minutes in heavy traffic. Each time, the owner pulled over, waited 10 minutes with engine running and A/C off, and the temperature returned to normal. Resuming driving in traffic caused the warning again.
The dealer performed:
Recommendation: Replace radiator (AED 18,000), water pump (AED 12,000), thermostat (AED 3,500), and flush cooling system (AED 2,500). Labour: AED 9,000.
Total quote: AED 45,000
When we reviewed this quote, two things stood out:
We idled the Bentayga in our workshop with the bonnet closed, simulating traffic conditions. After 12 minutes, coolant temperature reached 105°C and climbing. Normal workshop idle should stabilise at 92-95°C.
Observation: The primary cooling fans were operating at medium speed. They should have been at maximum speed above 100°C coolant temperature.
The Bentayga uses a two-stage electric cooling fan system:
ODIS diagnostic test — bi-directional fan control:
Physical inspection of auxiliary fan:
With the auxiliary fan issue identified, we inspected the auxiliary radiator (mounted in front of the main radiator).
Finding: The auxiliary radiator fins were 60-70% blocked with compressed sand, dust, and debris. Even if the fan had been working, airflow through this radiator was severely restricted.
Dubai connection: The Bentayga's low front bumper and large grille opening act as a dust collector in Dubai conditions. The auxiliary radiator, positioned in front of the main radiator, catches all incoming debris first. Without periodic cleaning, it progressively blocks — reducing the cooling system's total capacity by 15-25%.
The diagnosis explained the pattern perfectly:
Parts replaced:
Service performed:
Total: AED 1,500
Post-repair idle test in enclosed workshop:
Returned to the owner with recommendation: auxiliary radiator cleaning at every annual service (AED 300-400).
| Approach | Cost | Outcome | |----------|------|---------| | Dealer (radiator + pump + thermostat) | AED 45,000 | Would have cleaned radiator incidentally but not fixed the relay | | MotorMec (relay + radiator clean) | AED 1,500 | Root cause addressed | | Savings | AED 43,500 | 96.7% reduction |
Critical observation: The dealer's quote did not include the auxiliary fan relay. If the owner had approved the AED 45,000 work, the new radiator, water pump, and thermostat would have been installed — but the auxiliary fan would still be non-functional. The overheating in traffic would have continued, potentially leading to a second round of diagnosis and expense.
Q: How often should I clean my radiator in Dubai?
A: At every annual service — minimum. If you drive frequently in dusty conditions (construction areas, desert roads), every 6 months. The cleaning involves low-pressure water flush of the front radiator face and auxiliary radiator/condenser — takes 15-20 minutes and costs AED 300-400.
Q: Can overheating damage my W12 engine?
A: Yes — sustained overheating above 115°C risks head gasket failure, cylinder head warping, and turbocharger damage. The W12's compact cylinder arrangement means heat spreads quickly between cylinders. Any overheating warning should be addressed immediately: pull over, idle with A/C off, and do not continue driving if the temperature doesn't drop.
Q: Is the Bentayga more prone to overheating than other SUVs?
A: The W12 generates more heat than a comparable V8 due to 12 cylinders in a compact arrangement. Combined with the Bentayga's luxury-oriented low-drag front end (less aggressive airflow management than a performance SUV), the cooling system has less margin in extreme conditions. The V8 Bentayga has more thermal headroom.
Q: Should I add an aftermarket oil cooler or cooling fan?
A: The factory cooling system is adequate when properly maintained. The issue in this case wasn't capacity — it was a failed relay and blocked radiator. Before adding aftermarket cooling components, ensure the factory system is working at full capacity. Most "overheating" issues are maintenance problems, not design deficiencies.
Q: Is this relay failure common on Bentaygas?
A: Relay failures are common across all brands in Dubai. Relays contain mechanical contacts that degrade from thermal cycling and current load. In Dubai's engine bay temperatures, relay lifespan is reduced. We replace cooling system relays preventively during major service — they cost AED 100-200 each and prevent exactly this scenario.
A AED 180 relay and a blocked auxiliary radiator. That's what stood between a perfectly healthy W12 and a AED 45,000 quote for components that weren't failing.
Equipment. Knowledge. Patience. Sometimes the fix is embarrassingly simple. The skill is in finding it before recommending the expensive alternative.
No Fix, No Fee.
Reviewed by [Luxury Vehicle Specialist], MotorMec Dubai. Last updated: February 2026
