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Coolant Control Valve / Change Over Valves

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Product Information

Transmission oil cooler thermostat
OE Match transmission oil cooler thermostat for the listed Porsche Boxster, Cayman, 996 and 997 applications. This replacement component forms part of the transmission cooling system.

Fits
For cars with Tiptronic gearbox

  • Porsche 986 Boxster 1997 - 2004
  • Porsche 987.1 Boxster 2005 - 2008
  • Porsche 987.2 Boxster 2009 - 2012

  • Porsche 987C.1 Cayman 2005 - 2008
  • Porsche 987C.2 Cayman 2009 - 2012

  • Porsche 996 Carrera 1998 - 2005
  • Porsche 996 Turbo 2001 - 2005

  • Porsche 997.1 Carrera 2005 - 2008
  • Porsche 997.1 Turbo 2007 - 2009
  • Porsche 997.2 Carrera 2009 - 2012
  • Porsche 997.2 Turbo 2010 - 2013

Diagram ref no 8

What This Product Does

The thermostat is a control component within the transmission cooling arrangement, helping regulate its operation rather than serving as the oil cooler itself. OE Match develops replacement parts around Porsche applications, using original references and component specifications when assessing fit and function.

Symptoms of Fault

Transmission temperature warnings, rough changes when hot, delayed engagement or fluid leakage can justify inspecting the cooling system. These signs do not establish thermostat failure: cooler restrictions, damaged lines, seals and other transmission faults may produce similar symptoms.


Why Replacement Matters

Renewal is appropriate when diagnosis identifies a defective control component. Inspect associated hoses, connections and seals during the repair, and match the replacement to the vehicle's transmission specification.


FAQs

Will flushing resolve a faulty thermostat?
Flushing may address contamination, but it does not repair a defective component or leaking connection.

Does difficult shifting confirm a cooling fault?
No. Fluid condition, transmission controls and other drivetrain components should also be assessed before replacement.



Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

92857457305
92857457304
92857457303

The product you are viewing cross references to these numbers
Special Order item
92857457305::1
Product Information
Product Information
Transmission oil cooler thermostat

Fits:
For cars with Tiptronic gearbox
Porsche 986 Boxster 1997 - 2004
Porsche 987.1 Boxster 2005 - 2008
Porsche 987.2 Boxster 2009 - 2012

Porsche 987C.1 Cayman 2005 - 2008
Porsche 987C.2 Cayman 2009 - 2012

Porsche 996 Carrera 1998 - 2005
Porsche 996 Turbo 2001 - 2005

Porsche 997.1 Carrera 2005 - 2008
Porsche 997.1 Turbo 2007 - 2009
Porsche 997.2 Carrera 2009 - 2012
Porsche 997.2 Turbo 2010 - 2013

Diagram ref 8

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

92857457305
92857457304
92857457303
92857457305

The product you are viewing cross references to these numbers
DISPLAYING 1 to 2 (of 2 products)
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About 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       

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