MinorAffected: 2006-201460,000–120,000 miles

Vauxhall Corsa Corsa D 1.3 CDTi 75bhp — Engine Thermostat Sticking Open

The engine coolant thermostat fails in the 'open' position. The engine never reaches its optimal operating temperature, killing fuel economy.

Severity

Minor

DIY Difficulty

Moderate

Est. Cost

£100–£250

OBD Codes

P0128

Component Diagram

Cooling

Typical layout and location for the Cooling assembly.

Reference Illustration

Symptoms

Temperature gauge drops when driving on the motorway
Heater blows lukewarm air in winter
MPG drops significantly
Engine takes a very long time to warm up

Root Cause

The wax element inside the thermostat degrades, or the return spring weakens, preventing the valve from closing off coolant flow to the radiator.

How To Fix

Scan for P0128 (Coolant Thermostat - Coolant Temp Below Regulating Temp).
Replace the thermostat housing unit and gasket.
Bleed the cooling system of air.
Cost: £100-250

Estimated Repair Costs

Repair Option	Est. Cost (GBP)
DIY (parts only)	£40–£100
Independent Garage	£100–£250
Main Dealership	£160–£400

Other Faults on This Variant

EGR Valve Failure and Carbon Build-Up

Moderate

2006-201450,000–100,000 miles£80–£280

The Fiat/GM 1.3 CDTi is a capable diesel but its EGR valve blocks with carbon deposits regularly. This is one of the most common Corsa D complaints.

Diesel Particulate Filter Blockage

Moderate

2006-201440,000–90,000 miles£150–£800

DPF blockage is endemic on the 1.3 CDTi Corsa, largely because most owners use them for short trips where the DPF cannot self-clean.

EGR Valve Seized Open

Moderate

2006-201440,000–90,000 miles£150–£250

The EGR valve on the 1.3 CDTi clogs rapidly, usually jamming open and causing terrible starting and idling.

Disclaimer: Repair cost estimates are indicative and based on community data. Always get a quote from a qualified mechanic before proceeding with any repair.