Known JLR Fault
Land Rover Discovery Coolant & Overheating Problems
Affects
Overview
Coolant-related problems are disproportionately common on JLR's V6 diesel engines. The 2.7 TDV6, used in the Discovery 3 and early Range Rover Sport, has a particularly problematic EGR cooler that, when it fails internally, allows exhaust gas to contaminate the coolant system — leading to rapid head gasket failure if not caught early.
Symptoms
- ▶Rising coolant temperature gauge
- ▶Low coolant warning light with no visible external leak
- ▶Milky or chocolate-coloured coolant in expansion tank
- ▶White steam or smoke from exhaust on startup
- ▶Engine management light with coolant temperature sensor codes
- ▶Overheating at idle or in traffic after hard motorway driving
What Causes It?
- ✕EGR cooler internal failure (2.7 TDV6) — most common cause
- ✕Coolant water pump failure — both mechanical and electric auxiliary pumps
- ✕Head gasket failure — usually a consequence of prolonged overheating
- ✕Blocked radiator reducing cooling capacity
- ✕Coolant system air lock after partial coolant change
The Solution
Coolant problems on JLR V6 diesels should not be ignored. JLRMAN carries out a full coolant system inspection including pressure testing, combustion gas test (for head gasket integrity), and EGR cooler assessment. Early intervention — replacing the EGR cooler before it causes head gasket damage — is far cheaper than the alternative. We also carry out full coolant flushes and water pump replacement.
Experiencing This Fault?
Don't wait for it to get worse. JLRMAN diagnoses JLR faults correctly — and fixes them properly.
Related Service
Engine Repair
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Experiencing a JLR Fault?
Don't wait for it to get worse. JLRMAN diagnoses correctly the first time.