Coolant Control Valve / Change Over Valves

Porsche Transmission Coolant Control & Change Over Valves - Intelligent Gearbox Temperature Management

Porsche transmission coolant control valves, also known as change over valves, regulate the flow of coolant to the gearbox and transmission oil cooler. These valves ensure the transmission reaches optimal operating temperature quickly, then maintains stable cooling under load, improving efficiency, shift quality, and long-term gearbox reliability.

Available from Design911, transmission coolant control and change over valves are supplied to OEM standards, making them ideal for preventative maintenance, fault repair, and performance-focused thermal management.

What Do Transmission Coolant Control / Change Over Valves Do?

These valves manage when and how coolant is routed through the transmission cooling circuit.

Core Functions:

• Regulate coolant flow to the transmission oil cooler
• Help the gearbox warm up efficiently from cold
• Prevent over-cooling during light driving conditions
• Increase cooling during high load or high temperature operation
• Maintain consistent transmission oil temperature

Proper valve operation ensures balanced thermal control in all driving conditions.

Why Do Transmission Coolant Control Valves Fail?

Transmission coolant control valves operate in harsh thermal environments and are subject to wear over time.

Common Causes of Failure:

• Internal valve sticking due to coolant contamination
• Electrical actuator or solenoid failure
• Seal degradation from heat cycling
• Coolant leaks caused by cracked housings
• Age-related plastic fatigue

When these valves fail, transmission temperatures can fluctuate or remain outside optimal ranges.

When Should Transmission Coolant Control Valves Be Replaced?

Porsche transmission coolant control and change over valves should be replaced if any of the following symptoms are present:

• Transmission overheating or slow warm-up
• Warning lights or fault codes related to temperature control
• Inconsistent or harsh gear shifts when hot or cold
• Coolant leaks around the valve housing
• During gearbox or cooling system servicing

Early replacement helps prevent overheating, poor shifting, and premature gearbox wear.

Highlights

• Critical transmission thermal management components
• Regulates gearbox coolant flow and oil temperature
• Maintains efficient warm-up and cooling balance
• OEM-spec reliability for long-term durability
• Essential for both road and performance driving