OE Match

Tyre Pressure Monitoring System (TPMS or RDK) Tool Set for Nut and Sensor

This specialised TPMS fitting tool set is designed specifically for the Porsche 928 S4, 928 GT and 928 GTS models equipped with factory tyre pressure monitoring systems.

Fits:

• Porsche 928S4 5.0L 1987-92
• Porsche 928GT 5.0L 1989-91
• Porsche 928GTS 5.4L 1992-95

Tools for diagram Ref No 19  

Correct installation and removal of the original 928 RDK sensors requires the proper factory-style tools. Using incorrect tools can damage the sensor housing, securing nut or wheel assembly.

This complete set includes:
• Sensor nut tool with square pegs (for the retaining nut)
• Sensor body tool with round pegs (for the RDK sensor itself)

What This TPMS Tool Set Does

The Porsche 928 RDK system uses a two-part securing system inside the wheel:
1 - A retaining nut that secures the sensor assembly
2 -  The sensor body itself, which must be held or positioned correctly during removal or installation

The square peg tool (Porsche part number 00072192740) engages precisely with the sensor retaining nut.
The round peg tool (Porsche part number 00072192730) interfaces correctly with the RDK sensor body.

Together, they allow safe disassembly and reassembly without damaging rare and expensive components.

Why You Need the Correct 928 RDK Tools

Prevents Sensor Damage
Original Porsche 928 TPMS sensors are costly and increasingly hard to source. Using the proper peg tools prevents cracking or distortion during removal.

Protects Wheel Finish
Improvised tools can slip, causing damage to alloy wheels. These tools ensure precise engagement and controlled torque application.

Essential for Wheel Refurbishment
When refurbishing, powder coating or restoring Porsche 928 wheels, the RDK sensors must be removed correctly. This tool set is essential for professional-level work.

Ideal For
• Porsche specialist workshops
• Classic Porsche restoration projects
• Wheel refurbishment professionals
• 928 owners maintaining original RDK systems
• Safe sensor removal before powder coating wheels                                                                                 

The Rear Subframe Mount is a OE MATCH suspension component designed to secure the rear subframe to the vehicle chassis. This mount isolates vibration and road shock while maintaining precise alignment of the rear suspension assembly.
Sold Each.

Fits:

• Porsche 955 Cayenne 3.2L V6 2003-06
• Porsche 955 Cayenne S 4.5L V8 2003-06
• Porsche 955 Cayenne Turbo 4.5L 2003-06
• Porsche 955 Cayenne Turbo S 4.5L 2006>>
• Porsche 957 Cayenne 3.0L Diesel 2007-10
• Porsche 957 Cayenne 3.6L 2007-10
• Porsche 957 Cayenne S / GTS 4.8L 2007-10
• Porsche 957 Cayenne Turbo / Turbo S 4.8L 2007-10
• Porsche 958 Cayenne V6 3.6L Petrol (300Hp) 2010-17
• Porsche 958 Cayenne V6 3.0L Diesel (245Hp) 2010-17
• Porsche 958 Cayenne S V6 3.0L Hybrid (380Hp) 2010-17
• Porsche 958 Cayenne S V8 4.8L Petrol (400Hp) 2010-17
• Porsche 958 Cayenne S V8 4.2L Diesel (382Hp) 2010-17
• Porsche 958 Cayenne GTS V8 4.8L Petrol (400Hp) 2010-17
• Porsche 958 Cayenne Turbo V8 4.8L Petrol (500Hp) 2010-17
• Porsche 958 Cayenne Turbo S V8 4.8L Petrol (550Hp) 2010-17  

• Securing the rear subframe to the chassis
• Absorbing road vibration and impact
• Maintaining proper suspension alignment
• Supporting drivetrain stability (where applicable)
• Contributing to overall ride comfort and handling precision

• Clunking or knocking noises from the rear suspension
• Excessive vibration felt inside the cabin
• Rear-end instability or vague handling
• Uneven tyre wear
• Visible cracking or separation in the mount
• Misalignment issues

• Restore precise rear suspension alignment
• Improve ride comfort and reduce vibration
• Enhance vehicle stability and handling
• Prevent additional wear on suspension components
• Avoid costly repairs caused by prolonged misalignment

Porsche 928 Windscreen Washer Reservoir Filler Neck – Redesigned High-Strength Replacement

The Porsche 928 washer filler neck is a known weak point on ageing vehicles. Over time, the original part becomes brittle, cracks during removal, or suffers corrosion due to its internal metal ring.

We have completely redesigned this windscreen washer reservoir filler neck using modern 3D modelling technology to create a stronger, more durable and corrosion-resistant replacement suitable for all Porsche 928 model years — including early 1977 cars.

Fits:

• Porsche 928 4.5L 1978-82
• Porsche 928S 4.7L 1981-83
• Porsche 928S2 4.7L 1984-86
• Porsche 928S4 5.0L 1987-92
• Porsche 928GT 5.0L 1989-91
• Porsche 928GTS 5.4L 1992-95

Diagram Ref No 32

What This Filler Neck Does

The filler neck connects the washer bottle to the upper fill point, allowing washer fluid to be poured safely into the reservoir.

A damaged or cracked filler neck can cause:
• Washer fluid leaks inside the wing
• Difficulty filling the washer reservoir
• Fluid spillage during refilling
• Deterioration of surrounding bodywork

Replacing the filler neck restores correct washer system operation and prevents unnecessary leaks.

Why Upgrade to Our Redesigned Porsche 928 Washer Filler Neck?

Stronger Than the Original
Our redesigned version eliminates the structural weaknesses of the factory part. It is engineered for improved durability and long-term reliability.

No Internal Metal Ring
Unlike the original design, this filler neck does not use a metal reinforcement ring that can rust over time. This prevents corrosion-related failure.

Maintains Original Appearance
Now produced in white with a smooth surface finish to closely match the factory look. This ensures a clean and authentic engine bay appearance.

Fits All Left Hand Drive Porsche 928 Models
Designed to fit every LHD Porsche 928 from 1977 to 1995, including early production cars.

Compatible With Original Cap
The genuine Porsche cover cap fits directly onto this filler neck, maintaining OEM functionality and appearance.

Features
• Completely redesigned using 3D CAD
• High-strength construction
• No rust-prone metal ring
• White finish for factory-correct look
• Suitable for all Porsche 928 models (1977–1995)

Ideal For:
• Porsche 928 washer system restoration
• Replacing cracked or brittle filler necks
• Preventative maintenance on classic 928 models
• Engine bay refurbishment projects
• Solving washer fluid leak issues

Porsche 928 Power Steering Return Hose Repair Kit for Left Hand Drive (LHD)

Power steering return hoses on the Porsche 928 commonly begin to leak as the original rubber hardens and cracks with age. Heat, engine bay exposure and time cause deterioration, leading to fluid seepage or visible leaks.

Fits:

• Porsche 928S 4.7L 1981-83
• Porsche 928S2 4.7L 1984-86
• Porsche 928S4 5.0L 1987-92
• Porsche 928GT 5.0L 1989-91

Compatibility by Model and Part Number

Porsche 928 S2 (1983–1986)
Hose A + B for Return Hose - 92834744906 /  92834744917 / 92834744918

Porsche 928 S4 / GT / GTS (1986–1992)
A + C for Return Hose – 92834744907 / 92834744911 / 92834744909 / 92834744916

Please confirm your exact model and part number before ordering.
Professional Installation Required
Each hose section is supplied with a dedicated crimp sleeve. Installation must be carried out by a professional to ensure correct crimping and secure sealing.

Complete OEM replacement hoses are expensive. This repair kit provides a practical and cost-effective alternative by replacing only the flexible rubber hose sections while allowing you to reuse the original steel pipe assemblies.

What This Repair Kit Does

This kit replaces the flexible sections of the low-pressure power steering return line. The return hose carries fluid back to the reservoir and operates at low pressure, making it suitable for high-quality reinforced silicone replacement hose.

By installing this repair kit, you can:

• Eliminate leaks from aged rubber sections
• Retain the original factory steel hard lines
• Avoid the cost of complete OEM hose assemblies
• Restore safe and reliable power steering operation

Why Upgrade to This Silicone Repair Kit?

Significant Cost Saving
Original Porsche 928 power steering return hoses can be very expensive. This repair solution allows you to refurbish the existing assembly at a fraction of the cost.

High-Strength Silicone Construction
Manufactured from very strong, heat-resistant silicone, the replacement hose sections provide improved durability over ageing factory rubber.

Designed Specifically for 928 Applications
This kit is engineered to suit the correct hose diameters and routing used on Porsche 928 S2, S3, S4, GT and GTS models.

Safety Reminder
Power steering fluid is flammable. It is important to regularly inspect return hoses and address leaks immediately to reduce fire risk within the engine bay.

Porsche 928 Bumper Cap Set – Flexible Front & Rear Replacement
Sold as a pair - 2 fitted to each bumper 

Missing bumper caps are a common issue on classic Porsche 928 models. Over time, the original caps become brittle, fall out, or crack when pressed during removal. These small but visible trim pieces are often overlooked, yet they make a significant difference to the finished appearance of your bumper.

Fits:

• Porsche 928 4.5L 1978-82
• Porsche 928S 4.7L 1981-83
• Porsche 928S2 4.7L 1984-86
  
  

Diagram Ref No 19 

We have redesigned the Porsche 928 bumper cap to create a durable, flexible and high-quality replacement. Rather than producing a basic 3D printed replica, this cap is manufactured using professional vacuum forming technology. The result is a stronger, more consistent and more flexible product designed for long-term use.

What This Porsche 928 Bumper Cap Does

The bumper cap covers the access or mounting points in both the front and rear bumpers. Each bumper requires two caps.

A missing or broken cap can:

• Leave visible holes in the bumper
• Detract from the vehicle’s appearance
• Allow dirt and moisture into bumper cavities
• Reduce originality during restoration

Replacing worn or missing caps restores a clean, factory-correct finish.

Why Upgrade to Our Redesigned Flexible Bumper Caps?

Vacuum Formed – Not Basic 3D Printed
Unlike simple printed parts, these caps are produced using vacuum form technology, delivering superior flexibility and durability.

Flexible Polyamide Construction
Manufactured from polyamide, the caps are flexible enough to allow easy installation and removal without cracking. This significantly reduces the risk of damaging your bumper during fitting.

Improved Durability Over Aged Originals
Original Porsche 928 bumper caps often become brittle with age. Our redesigned version maintains flexibility, helping prevent breakage when pressed or removed.

Suitable for Front and Rear Bumpers
These caps fit both the front and rear bumpers. There are two caps per bumper, so please check how many are missing or test your existing ones carefully, as old caps frequently break when handled.

Paintable Surface
Supplied in black as per original factory finish. However, they can be painted to match bumper colour if desired by lightly keying the surface before spraying.

Product Details
• Part Number: 92850513102
• Quantity: 2 pieces
• Material: Polyamide
• Suitable for painting
• Fits front and rear bumpers

Porsche 928 Washer Filler Neck to Reservoir Hose Kit – Cost-Effective Replacement

Over time, the original hose running from the washer filler neck to the windshield washer reservoir on the Porsche 928 becomes brittle, cracked or torn. Exposure to heat, age and washer fluid chemicals causes deterioration, leading to leaks and inefficient washer system operation.

Fits:

• Porsche 928 4.5L 1978-82
• Porsche 928S 4.7L 1981-83
• Porsche 928S2 4.7L 1984-86
• Porsche 928S4 5.0L 1987-92
• Porsche 928GT 5.0L 1989-91
• Porsche 928GTS 5.4L 1992-95

Diagram Ref No 12 and 13

What This Hose Kit Does

This hose connects the washer filler neck to the windshield washer reservoir, allowing fluid to flow properly into the tank during filling.

A damaged or perished hose can cause:

• Washer fluid leaks inside the wing area
• Slow or incomplete filling of the reservoir
• Fluid loss before reaching the tank
• Unpleasant odours from trapped washer fluid

Replacing the hose restores correct washer system function and prevents fluid loss.

Why Upgrade to This Replacement Kit?

Replaces a Discontinued Porsche Part
The original Porsche 928 washer filler neck hose is no longer available. This kit provides a direct-fit alternative to keep your washer system operational.

Cost-Effective Solution
This set offers a more affordable option compared to sourcing rare original parts, making it ideal for both maintenance and restoration projects.

Compatible with Our New Filler Neck
Fully compatible with the replacement filler necks available from Design911, ensuring correct fitment and installation.

Suitable for All Model Years
Designed to fit Porsche 928 models from 1977 to 1995, covering early and late variants.

Complete Kit for Installation
Supplied with hose and clamps for secure fitting.

Package Contents
1 x Water hose 
 2 x Hose clamps 

Ideal For:
• Porsche 928 washer system repair
• Replacing cracked or leaking washer hoses
• Restoration projects
• Preventative maintenance on ageing vehicles
• Replacing NLA Porsche washer components

The Coolant Hose – Outlet is a OE MATCH cooling system component designed to carry coolant away from the engine toward the radiator or adjoining cooling components. As an outlet hose, it plays a critical role in directing heated coolant out of the engine for heat dissipation.

Fits:

• Porsche 957 Cayenne S / GTS 4.8L 2007-10
• Porsche 957 Cayenne Turbo / Turbo S 4.8L 2007-10
• Porsche 958 Cayenne S V8 4.8L Petrol (400Hp) 2010-17
• Porsche 958 Cayenne GTS V8 4.8L Petrol (400Hp) 2010-17
• Porsche 958 Cayenne Turbo V8 4.8L Petrol (500Hp) 2010-17
• Porsche 958 Cayenne Turbo S V8 4.8L Petrol (550Hp) 2010-17

• Carrying heated coolant away from the engine
• Maintaining steady coolant circulation
• Supporting correct cooling system pressure
• Helping regulate engine operating temperature
• Ensuring efficient heat exchange within the radiator system

• Coolant leaks near the hose or connection points
• Cracked, brittle, swollen, or softened hose material
• Coolant smell from the engine bay
• Low coolant warning light
• Engine overheating or fluctuating temperature readings
• Steam from the engine compartment
• Coolant residue around hose fittings

• Prevent sudden coolant leaks and breakdowns
• Maintain proper coolant circulation and temperature control
• Protect engine components from overheating damage
• Restore reliable cooling system performance
• Avoid costly repairs caused by cooling system failure

The Heating Hose – Hose Set With Clips (LHD) is a OE MATCH heating and cooling system assembly designed specifically for left-hand drive (LHD) vehicles. Supplied as a complete set, this kit ensures secure coolant circulation between the engine and heater core, supporting consistent cabin heating performance.

Fits:

• Porsche 95B.1 Macan Petrol 2.0L (237Bhp) 2014-18
• Porsche 95B.1 Macan S Petrol 3.0L V6 (340Bhp) 2014-18
• Porsche 95B.1 Macan GTS Petrol 3.0L V6 (360Bhp) 2014-18
• Porsche 95B.1 Macan Turbo 3.6L V6 (400Bhp) 2014-18

• Transferring coolant to and from the heater core
• Maintaining steady coolant circulation through the heating circuit
• Supporting proper cabin heating performance
• Ensuring secure hose connections with included factory clips
• Helping maintain stable engine operating temperature

• Coolant leaks near the firewall or heater hose connections
• Sweet coolant smell inside or outside the vehicle
• Low coolant warning light
• Reduced or inconsistent cabin heating
• Cracked, brittle, or swollen hose material
• Engine overheating if coolant loss becomes significant
• Coolant residue around hose joints

• Prevent coolant leaks and unexpected breakdowns
• Maintain consistent cabin heating performance
• Protect the engine from overheating damage
• Ensure correct hose routing and secure connections
• Avoid costly repairs caused by cooling system failure

Porsche Rear Hatch Lock & Automatic Door Lock Connector – NLA Electrical Repair Solution

This small but essential Porsche electrical connector is no longer available (NLA) new from Porsche. When it fails, becomes brittle or breaks during removal, repairing the wiring can be time-consuming and frustrating.

Fits:

• Porsche 911 1965-1968 2.0L / 912 SWB (F)
• Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
• Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
• Porsche 911 1978-1983 3.0L / SC
• Porsche 911 1984-1986 3.2L
• Porsche 911 1987-1989 3.2L G50
• Porsche 911 1975-1977 3.0L Turbo (930)
• Porsche 911 1978-1989 3.3L Turbo (930)
• Porsche 944 2.5L 8V 1982-87
• Porsche 944 2.7L 8V 1988-89
• Porsche 944S 2.5L 16V 1987-88
• Porsche 944S2 3.0L 16V 1989-91
• Porsche 944 Turbo 2.5L 8V 1985-88
• Porsche 944 Turbo 2.5L 8V 1989-91
• Porsche 944 Turbo S 2.5L 8V 1988
• Porsche 968 3.0L 1992-94
• Porsche 968 Sport 3.0L 1994-95
• Porsche 968 CS 3.0L 1993-95
• Porsche 968 Turbo S 3.0L 1993-95
• Porsche 928 4.5L 1978-82
• Porsche 928S 4.7L 1981-83
• Porsche 928S2 4.7L 1984-86
• Porsche 928S4 5.0L 1987-92
• Porsche 928GT 5.0L 1989-91
• Porsche 928GTS 5.4L 1992-95

Diagram Ref No 7 

To solve this problem, we have designed and 3D printed a high-quality replacement connector in-house at Design911. It provides a reliable, cost-effective solution for restoring proper electrical connection without searching for obsolete factory parts.

What This Connector Does

This replacement plug restores the electrical connection for:
• Engine rear hatch lock (3 active pins)
• Automatic door locking motor (4 active pins)

A damaged or cracked connector can lead to intermittent operation, non-functioning hatch release, or automatic locking faults. Replacing the connector ensures proper signal transmission and reliable system performance.

Why Upgrade to This Replacement Connector?

Replaces a No Longer Available Porsche Part
As the original connector is discontinued (NLA), sourcing a genuine replacement is extremely difficult. This in-house developed solution eliminates that issue.

Saves Time During Repairs
The original connector is known for being difficult to remove and repair. Our replacement simplifies the process, helping reduce labour time during wiring or locking system repairs.

Precision 3D Printed Design
Manufactured using modern 3D printing technology, this connector is engineered for accurate fitment and dependable durability.

Supplied Ready for Installation
Each connector is supplied with 4 male pins, allowing proper electrical termination and secure connection.

Ideal for Restoration and Electrical Repairs
Perfect for ageing vehicles where brittle plastics and wiring connectors commonly fail.

Applications
• Porsche rear hatch lock wiring repair
• Porsche automatic door locking motor connector replacement
• Fixing broken or cracked Porsche electrical plugs
• Restoration of hatch and central locking systems

The Engine Coolant Breather Line is a OE MATCH cooling system component designed to vent trapped air and regulate pressure within the engine’s coolant circuit. This breather hose ensures efficient coolant circulation by preventing air pockets that can reduce cooling performance and cause temperature instability.

Fits:

• Porsche 9YA Cayenne GTS V8 4.0L Petrol (460Hp) 2020-23
• Porsche 9YA Cayenne Coupe GTS V8 4.0L Petrol (460Hp) 2021-23
• Porsche 9YA Cayenne Turbo V8 4.0L Petrol (550Hp) 2020-23
• Porsche 9YA Cayenne Coupe Turbo V8 4.0L Petrol (550Hp) 2019-23
• Porsche 9YA Cayenne Turbo S E-Hybrid V8 4.0L (550Hp) 2019-23
• Porsche 9YA Cayenne Coupe Turbo S E-Hybrid V8 4.0L (550Hp) 2020-23
• Porsche 9YA.2 Cayenne S V8 4.0L Petrol (474Hp) 2023>>
• Porsche 9YA.2 Cayenne S Coupe V8 4.0L (474Hp) 2023>>

• Allowing trapped air and vapour to vent from the coolant circuit
• Preventing airlocks that reduce cooling efficiency
• Maintaining correct cooling system pressure
• Supporting steady coolant flow
• Helping regulate engine operating temperature

• Coolant leaks near hose connections
• Cracked, brittle, or split hose material
• Coolant smell from the engine bay
• Low coolant warning light
• Difficulty bleeding the cooling system
• Fluctuating or rising engine temperature
• Coolant residue around fittings

• Maintain correct cooling system pressure
• Prevent airlocks and circulation issues
• Protect the engine from overheating damage
• Restore reliable coolant flow
• Avoid costly repairs caused by cooling system failure

Porsche 944 & 924S Crankshaft Oil Scraper – Improved Oil Control & Engine Stability Upgrade

This unique crankshaft oil scraper is designed to improve oil control, reduce rotating drag and increase engine reliability in Porsche 924S, 944 and 944S models.

Fits:

• Porsche 924S 2.5L 1986-87
• Porsche 924S 2.5L 1988
• Porsche 944 2.5L 8V 1982-87
• Porsche 944 2.7L 8V 1988-89
• Porsche 944S 2.5L 16V 1987-88

In high-revving engines, the crankshaft spins through engine oil at great speed. As it rotates, it throws oil outward, creating a dense cloud of oil mist around the crank assembly. This phenomenon increases rotating resistance, aerates the oil and reduces the amount of usable oil retained in the sump.

Our precision-engineered crank scraper directly removes excess oil from the crank cheeks on every rotation. The result is improved oil control, reduced drag and enhanced engine stability.

What This Crankshaft Oil Scraper Does

Reduces Rotational Drag
By scraping excess oil from the crankshaft during rotation, the scraper reduces the weight of the crankshaft in wet running conditions. Less oil clinging to the rotating assembly means smoother, freer revving performance.

Improves Oil Retention in the Sump
Instead of being whipped into suspension, more oil remains in the crankcase where it belongs. This ensures a more stable oil supply under acceleration and high RPM use.

Reduces Oil Foaming and Aeration
Excessive oil mist leads to foaming, which can reduce lubrication efficiency. By controlling oil splash, this scraper helps maintain more consistent oil density and lubrication quality.

Helps Prevent Oil Starvation
During hard cornering, braking or high-speed driving, oil starvation can occur when insufficient oil reaches the suction pipe. By keeping more oil properly settled in the sump and reducing aeration, the risk of oil starvation is significantly reduced.

Increases Crankshaft Frame Stiffness
This component also adds structural rigidity to the crankshaft frame assembly. When installed, the rings under the crankshaft frame nuts are omitted, contributing to a more direct and stable mounting setup.

Precision Fitment
We have measured tolerances on used engines with maximum axial play to ensure accurate fitment across engine conditions. The design also allows compatibility with our H-beam connecting rods, making it ideal for performance builds and engine rebuild projects.

Ideal for Performance and Track Use
High RPM and track conditions amplify oil aeration and starvation risks. This upgrade provides additional protection for engines operating under stress.

Engine Rebuild Enhancement
If you are rebuilding a Porsche 944 or 924S engine, installing a crank scraper is a smart preventative upgrade that improves long-term reliability.

Improved Engine Efficiency
Reducing oil drag on the crankshaft can contribute to smoother power delivery and improved engine response.

Long-Term Engine Protection
By minimising oil foaming and maintaining stable oil supply to the pickup pipe, this component supports bearing longevity and overall engine durability.

If you are building, restoring or upgrading a Porsche 924S or 944 engine, this crankshaft oil scraper is a proven solution to improve oil control, reduce drag and enhance engine stability under demanding conditions.

The Coolant Hose Pipe is a OE MATCH cooling system component designed to route coolant efficiently between critical engine and radiator circuit components. Combining the flexibility of a hose with the structural stability of a formed pipe section, this component ensures reliable coolant transfer under high-temperature and high-pressure conditions.

Fits:

• Porsche 9YA Cayenne V6 3.0L Petrol (340Hp) 2018-23
• Porsche 9YA Cayenne Coupe V6 3.0L Petrol (340Hp) 2019-23
• Porsche 9YA Cayenne S V6 2.9L Petrol (440Hp) 2018-23
• Porsche 9YA Cayenne Coupe S V6 2.9L Petrol (440Hp) 2019-23
• Porsche 9YA.2 Cayenne V6 3.0L Petrol (353Hp) 2023>>
• Porsche 9YA.2 Cayenne Coupe V6 3.0L (353Hp) 2023>>

• Directing coolant flow through the cooling circuit
• Maintaining steady coolant circulation
• Supporting correct cooling system pressure
• Ensuring secure connections between cooling components
• Helping prevent overheating during normal and demanding driving

• Coolant leaks near hose or pipe connections
• Cracked, brittle, or swollen hose sections
• Corrosion or surface damage on pipe sections
• Coolant smell from the engine bay
• Low coolant warning light
• Engine overheating or fluctuating temperature readings
• Coolant residue around fittings

• Prevent sudden coolant leaks and breakdowns
• Maintain proper coolant flow and system pressure
• Protect engine components from overheating damage
• Restore reliable cooling system performance
• Avoid costly repairs caused by cooling system failure