Genuine OEM 1162000315 - Engine Coolant Thermostat

Product Overview

This Genuine OEM 1162000315 engine coolant thermostat is the factory-spec component for Mercedes-Benz W126 (420SEL, 560SEL, 560SEC), R107 (560SL, 500SL), W124 (400E, 500E, E420, E500), and W140 (S420, S500) models from 1986 to 1996. The thermostat regulates coolant flow to maintain optimal engine operating temperature, ensuring efficient combustion and preventing overheating. As a Genuine Mercedes-Benz part, this thermostat meets factory specifications and carries dealership warranty confidence for critical cooling system service.

This thermostat is a single component. Order quantity 1 per vehicle.

Symptoms of a Failing Engine Coolant Thermostat

• Engine running hotter than normal; temperature gauge climbing toward the red zone
• Coolant leaking from the thermostat housing or surrounding gasket area
• Erratic temperature gauge behavior; needle fluctuating between normal and hot
• Reduced cabin heat output, especially during cold starts or city driving
• White coolant residue or crusty deposits around the thermostat housing
• Cooling fan running continuously without cycling off

Cross Reference Numbers

This Genuine OEM 1162000315 is equivalent to or replaces the following part numbers: 116200031500, 1162000315, 116-200-03-15.

Vehicle Compatibility

This part fits the popular models below. For Fitment Confidence, please use the vehicle selector tool above to verify exact compatibility for your vehicle.

• Mercedes-Benz 420SEL (W126): 1986–1991
• Mercedes-Benz 560SEL (W126): 1986–1991
• Mercedes-Benz 560SEC (C126): 1986–1991
• Mercedes-Benz 560SL (R107): 1986–1989
• Mercedes-Benz 500SL (R107): 1990–1991
• Mercedes-Benz 400E (W124): 1992–1993
• Mercedes-Benz 400SEL (W124): 1992–1993
• Mercedes-Benz 500E (W124): 1992–1993
• Mercedes-Benz 500SEL (W124): 1992–1993
• Mercedes-Benz 500SL (R107): 1992–1993
• Mercedes-Benz 500SEC (C126): 1993
• Mercedes-Benz E420 (W124): 1994–1995
• Mercedes-Benz E500 (W124): 1994
• Mercedes-Benz S420 (W140): 1994–1995
• Mercedes-Benz S500 (W140): 1994–1995
• Mercedes-Benz SL500 (R231): 1994–1996

This may also fit other applications. Please use the vehicle selector tool to verify fitment.

Often Replaced Together

For a complete cooling system service, many owners replace the following at the same time:

• Coolant hoses and clamps (upper and lower radiator hoses)
• Engine coolant (flush and refill with proper Mercedes-Benz specification fluid)
• Water pump (if mileage is high or pump shows wear)
• Radiator cap (pressure relief valve wear)

Why Shop at eEuroparts.com?

• Proven Expertise: Over 25 years of experience with European vehicles means we know your car inside and out.
• Fitment Confidence: Our accurate cataloging ensures you get the right part the first time, backed by our fitment guarantee.
• Fast, Reliable Shipping: Most in-stock orders ship the same or next business day from our U.S.-based warehouse.
• Transparent Pricing: Competitive prices with no hidden fees or surprise charges.
• Exclusive Kits That Fit™: Complete repair solutions with no guesswork.
• Established Trust: Serving the European car community since 2000.

Frequently Asked Questions

How do I know if my Mercedes-Benz W126, W124, or R107 thermostat is failing?

The most common sign is an engine that runs hotter than normal or a temperature gauge that fluctuates erratically. You may also notice coolant leaking from the thermostat housing, white crusty deposits around the housing, or a cooling fan that runs constantly without cycling off. If the cabin heater produces less warm air than usual, the thermostat may be stuck in the open position. Any of these symptoms warrants inspection and replacement.

Is this a Genuine Mercedes-Benz part?

Yes. This 1162000315 is a Genuine OEM Mercedes-Benz thermostat manufactured to factory specifications. It is the exact same part supplied to Mercedes-Benz dealerships for warranty service and original equipment assembly. Using a Genuine part ensures proper fit, function, and durability for your cooling system.

What is the purpose of the engine coolant thermostat?

The thermostat is a temperature-sensitive valve that regulates the flow of coolant from the engine to the radiator. When the engine is cold, the thermostat stays closed to allow the engine to warm up quickly. Once the engine reaches operating temperature, the thermostat opens to allow coolant to circulate through the radiator for heat dissipation. A properly functioning thermostat keeps your engine in the ideal temperature range for performance and longevity.

How long does a thermostat typically last?

Engine coolant thermostats are generally durable components, but they can fail due to age, corrosion from coolant breakdown, or thermal cycling stress. Many thermostats last 100,000 miles or more, but failure can occur earlier if the coolant is not flushed regularly or if the cooling system is contaminated. Inspect the thermostat if you notice cooling system symptoms, and replace it if leaking or stuck.

What tools and expertise do I need to replace this thermostat?

Thermostat replacement typically requires basic hand tools, a socket set, a drain pan for coolant, and jack stands if you need access from underneath. Many W124, W126, and R107 thermostats are accessible from the engine bay without major disassembly, though the exact location varies by model and engine. Consult your factory service manual for the specific procedure, coolant drain points, and refill capacity for your vehicle. If you are not comfortable working with coolant systems, a professional technician can complete the job quickly.

Should I flush my cooling system when I replace the thermostat?

Yes, it is highly recommended. Over time, coolant becomes acidic and can deposit rust and corrosion inside the cooling system. A coolant flush removes old fluid and contaminants, which helps prevent future thermostat failure and extends the life of other cooling components like the water pump and radiator. Use the correct Mercedes-Benz coolant specification for your model year, as mixing incompatible fluids can cause corrosion and blockages.

Why Shop at eEuroparts.com?

• Proven Expertise: Over 25 years of experience with European vehicles means we know your car inside and out.
• Fitment Confidence: Our accurate cataloging ensures you get the right part the first time, backed by our fitment guarantee.
• Fast, Reliable Shipping: Most in-stock orders ship the same or next business day from our U.S.-based warehouse.
• Transparent Pricing: Competitive prices with no hidden fees or surprise charges.
• Exclusive Kits That Fit™: Complete repair solutions with no guesswork.
• Established Trust: Serving the European car community since 2000.

Order Genuine Mercedes-Benz 1162000315 thermostat today. In-stock orders ship same or next business day from our U.S. warehouse, and our fitment team is one call away if you need help confirming the right part for your Mercedes-Benz W126, W124, or R107.

Note: All information on this page and in the FAQ is for general reference only. Verify fitment and consult a professional as needed. eEuroparts.com is not responsible for incorrect part selection or installation.