Oil Thermostat
All pipes and fittings are precision-engineered to meet factory specifications for perfect fitment and reliable, leak-free operation.
Fits:
Porsche 964 - 1989 to 1994
Kit includes
1 x Oil thermostat
1 x Oil hose - thermostat to oil tank
1 x Oil hose
- thermostat to oil tank
1 x Oil hose - thermostat to oil filter housing
Diagram Ref No 21, 22, 46 and 11
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
96420704708
The product you are viewing cross references to these numbers
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93

Fits:
Porsche 964 1989-94
*For cars with Thermostat Part Number:
96420704705
96420704307
96420704308
Diagram ref no 22
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
96420725103
The product you are viewing cross references to these numbers
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
Fits:
Porsche 964 1989-94
*For cars with Thermostat Part Number:
96420704705
96420704707
96420704708
Diagram ref no 22
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
96420725103
The product you are viewing cross references to these numbers
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93

These are long pipes running down the side of the car
Fits:
Porsche 964 1989-94 3.6L
Porsche 964 Turbo
Diagram Ref No 2
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
96420713304
The product you are viewing cross references to these numbers
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
These are long pipes running down the side of the car
Fits:
Porsche 964 1989-94 3.6L
Porsche 964 Turbo
Diagram Ref No 2
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
96420713304
The product you are viewing cross references to these numbers
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93

Fits:
Porsche 964 C2 / C4 / RS 1989-94
This product supersedes Porsche's old part numbers:
- 96420725404
- 96420725405
- 96420725406
- 96420725407
Diagram Ref No 46
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
96420725414
The product you are viewing cross references to these numbers
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93
Fits:
Porsche 964 C2 / C4 / RS 1989-94
This product supersedes Porsche's old part numbers:
- 96420725404
- 96420725405
- 96420725406
- 96420725407
- 96420725408
Diagram Ref No 46
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
96420725414
The product you are viewing cross references to these numbers
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93


Fits: 964 Carrera 2 / Carrera 4 1989-94
Click 'Zoom in' for large parts diagram.
Diagram Ref No 14.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
96420735101
The product you are viewing cross references to these numbers
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93

Fits:
Porsche 964 1989-94
Click 'Zoom in' for large parts diagram.
Diagram Ref No 13.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
96420734902
The product you are viewing cross references to these numbers
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93


Fits:
Porsche 964 1989-94
Please note: For early models with the early type thermostat you will also need:
96420724107 - Oil hose for thermostat
96420725103 - Oil pipe rubber (oil tank to thermostat)
Click 'Zoom in' for large parts diagram.
Diagram Ref No 11.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
96420704708
The product you are viewing cross references to these numbers
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93

Fits:
Porsche 964 1989-94
Please note: For early models with the early type thermostat you will also need:
96420724107 - Oil hose for thermostat
96420725103 - Oil pipe rubber (oil tank to thermostat)
Click 'Zoom in' for large parts diagram.
Diagram Ref No 11.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
96420704708
The product you are viewing cross references to these numbers
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93


Fits:
Porsche 964 1990-94
Porsche 993 1994-97
Click picture for large parts diagram.
Diagram Ref No 9.
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
- Porsche 993 (911) C2 1994-97
- Porsche 993 (911) C4 1994-97
- Porsche 993 (911) RS 1994-97
- Porsche 993 (911) C2S 1994-97
- Porsche 993 (911) C4S 1994-97
- Porsche 993 (911) TURBO 1994-96
- Porsche 993 (911) GT2 1994-97
- Porsche 993 (911) TURBO S 1994-97
Oil Thermostats – Precision Temperature Regulation for Porsche Engines
The oil thermostat plays a vital role in your Porsche’s lubrication and cooling system by controlling oil flow based on temperature. It ensures that your engine oil warms up quickly to the ideal operating temperature and maintains stability during demanding driving conditions. This optimised oil temperature improves performance, efficiency, and long-term engine protection.
At Design911, we supply a range of oil thermostats and related components designed for reliability and accuracy across both classic and modern Porsche models. Manufactured using high-quality heat-resistant alloys and durable seals, our thermostats guarantee smooth operation, consistent flow control, and a perfect fit for your Porsche’s lubrication system.
Whether you’re maintaining a 911, Cayman, or Panamera, our oil thermostats deliver the precise temperature regulation your engine demands for both everyday use and performance driving.
What Do Oil Thermostats Do?
An oil thermostat regulates when oil is diverted through the oil cooler, based on temperature readings.
Core Functions:
- Control
oil flow between the engine and the oil cooler.
- Ensure
rapid oil warm-up to reduce cold-start wear.
- Maintain
stable operating temperatures during all conditions.
- Protect
against overheating under high loads.
- Support optimal lubrication and efficiency.
By keeping oil within the correct temperature range, the thermostat helps your Porsche achieve consistent performance, better fuel economy, and extended engine life.
Why Do Oil Thermostats Fail?
Over time, continuous exposure to high temperatures, oil contamination, and mechanical wear can cause oil thermostats to degrade or malfunction.
Common Causes of Failure Include:
- Sticking
or seized valves due to sludge or varnish build-up.
- Thermal
fatigue from repeated heating and cooling cycles.
- Cracked
housings or worn seals, leading to leaks.
- Oil
contamination affecting thermal response.
- Improper temperature regulation, causing overheating or slow warm-up.
Signs of a failing thermostat include oil temperature
fluctuations, overheating, or delayed oil circulation, which can result in
reduced engine protection and performance.
Why Replace Oil Thermostat Components?
A faulty thermostat can cause erratic oil flow, engine wear, or overheating. Replacing it with a high-quality, precision-engineered unit ensures reliable temperature control, smoother oil circulation, and consistent lubrication.
Key Benefits:
- Restores accurate oil temperature regulation.
- Prevents overheating and cold-start damage.
- Improves oil flow and engine efficiency.
- Built from heat- and corrosion-resistant materials.
- Direct-fit
compatibility with a wide range of Porsche models.
- Ideal for servicing, engine rebuilds, or performance upgrades.
Replacing an ageing thermostat is an essential part of maintaining your Porsche’s lubrication system and preventing premature engine wear.
Highlights:
- Precision-engineered Porsche oil thermostats for reliable control.
- Ensures optimal oil flow and temperature regulation.
- Constructed from premium heat-resistant materials.
- Direct-fit design for 911, Cayman, Boxster, Panamera and more.
- Ideal for routine maintenance or high-performance applications.
- Maintains peak engine performance and longevity.