Volvo S60 Engine Coolant Thermostat Guide (2001-2010)
Keep your S60's engine temperature in check by understanding common thermostat problems and how to choose the right replacement part.
- A thermostat stuck open is the most common failure, causing a P0128 code and poor heating.
- For best reliability, choose an OEM-supplier brand like Calorstat or a reputable aftermarket brand like Gates.
- Consider replacing the entire thermostat housing assembly, not just the insert, to prevent future leaks, especially on 2005+ models.
- While you are replacing the thermostat, it is a smart and cost-effective move to also replace the Engine Coolant Temperature (ECT) sensor.
Is Your S60 Thermostat Failing?
A thermostat is a wear item, and with the 2001-2010 S60 models getting older, failures are common. A thermostat can fail by getting stuck open or stuck closed, each causing distinct problems.
Common Failure Symptoms
- Engine Overheating: If the thermostat is stuck closed, coolant can't get to the radiator to cool down. This is the most serious failure, causing the temperature gauge to spike and potentially leading to severe engine damage.
- Engine Running Too Cold: A thermostat stuck open allows coolant to circulate constantly, preventing the engine from reaching its proper operating temperature. This often triggers a Check Engine Light with code P0128.
- Temperature Gauge Fluctuating: A needle that moves around erratically can indicate the thermostat is opening and closing at the wrong times.
- Poor Heater Performance: If your engine isn't getting hot enough, the air blowing from your heater vents will be lukewarm at best, a common issue in winter.
- Coolant Leaks: The thermostat housing can develop cracks or the gasket can fail, leading to coolant puddles under your car.
Choosing the Right Aftermarket Thermostat
For the 2001-2010 S60, you can buy just the thermostat insert or the complete housing assembly, which often includes a new coolant temperature sensor. For models around 2005 and later, Volvo changed the housing design, making it more common to replace the entire assembly due to potential sealing issues when just replacing the insert. Given the age of the plastic, replacing the whole housing is often the safer bet.
🎬 See this walkthrough for replacing the thermostat on 2003-2009 models.Brand Quality Tiers
- OEM Supplier / Premium Aftermarket: Brands like Calorstat (by Vernet) and Wahler are often the original equipment manufacturers for Volvo. Choosing one of these is the closest you can get to dealer quality. Beck Arnley is also known for rebranding OEM parts and is generally a reliable choice.
- Quality Aftermarket: Gates is a well-respected brand in cooling systems and offers reliable thermostats. Many owners have used them with good results.
- Performance: Mishimoto offers performance-oriented thermostats, which may open at a slightly lower temperature. These are high-quality but come at a premium price and are generally not necessary for a daily driven vehicle.
- Budget-Friendly: Brands like Motorad, Facet, and Professional Parts Sweden are more budget-oriented. While they can be a cost-effective solution, some owners report mixed results and a shorter lifespan compared to premium brands. A Professional Parts Sweden housing was noted to have leaked in one owner's experience.
Pro Tip: Since the thermostat and Engine Coolant Temperature (ECT) sensor are in the same housing, it's highly recommended to replace them both at the same time. This can prevent you from having to do the same job twice.
Cost of Replacing a Volvo S60 Thermostat
| Part Type | Estimated Cost |
|---|---|
| New Aftermarket Thermostat (Insert Only) | $12 - $40 |
| New Aftermarket Thermostat (Full Housing Assembly) | $45 - $190 |
| Shop Labor | $120 - $250 |
Note: Costs are estimates and can vary based on location, brand, and vehicle specifics.
Frequently Asked Questions
Is there a recall on the 2001-2010 S60 thermostat?
No, searches of the NHTSA database show no specific recalls for the engine coolant thermostat on the 2001-2010 Volvo S60. Later model year S60s had recalls related to cooling systems for hybrid models, but these do not apply to the 2001-2010 generation.
Can I replace only the thermostat or do I need the whole housing?
On earlier models in this range, you can often just replace the thermostat insert. However, on models from roughly 2005-onward, Volvo used a housing design that can be difficult to re-seal properly. Many mechanics and DIYers recommend replacing the entire housing assembly to prevent leaks, especially since the original plastic can become brittle with age.
What is the P0128 code?
The P0128 code means "Coolant Temperature Below Thermostat Regulating Temperature." This code is set by your car's computer when the engine fails to reach its normal operating temperature in a set amount of time. The most common cause for this on an S60 is a thermostat that is stuck open.
🎬 Watch: How to diagnose and fix the P0128 engine code.Is it difficult to replace the S60 thermostat myself?
For a DIYer with some experience, this job is manageable. It typically involves draining some coolant, removing the serpentine belt, and unbolting the power steering pump to gain access. The thermostat housing is held on by Torx bolts which can be in tight spaces. The job can take 1-2 hours.
🎬 Watch: Step-by-step thermostat replacement guide for P2 chassis Volvos.Helpful Videos
Technical Specifications
OEM Part Numbers: 31355151
Fits 2.3L, 2.4L, and 2.5L 5-cylinder engines. Available as thermostat insert or complete housing assembly. Standard opening temperature is typically 90°C (194°F).
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Volvo S60: