Saab 900 Engine Coolant Thermostat Guide for 1985-1993 Models
Keep your classic Saab 900's engine temperature stable by choosing the right replacement thermostat.
- A failing thermostat can cause overheating (stuck closed) or a cold-running engine (stuck open).
- Always install the new thermostat with the small bleed pin at the 12 o'clock position to prevent air pockets.
- For reliability, choose a Genuine Saab/OES thermostat; the cost is often similar to aftermarket options.
- Avoid the Professional Parts Sweden (PPS) brand for this part due to widespread reports of poor quality.
Signs of a Failing Thermostat in Your Saab 900
A thermostat can fail in two ways: stuck open or stuck closed. A stuck-closed thermostat is the most dangerous, as it will block coolant flow and cause the engine to overheat quickly. A stuck-open thermostat, which is a very common failure, will prevent your engine from reaching its proper temperature, especially in cooler weather.
- Engine Overheating: The temperature gauge climbs into the red zone. This is a critical issue that requires you to stop driving immediately to prevent severe engine damage.
- Engine Running Too Cool: The temperature gauge stays in the cold range or never reaches the middle (9 o'clock) position. This can lead to poor fuel mileage and reduced heater performance.
- Fluctuating Temperature Gauge: The needle may move up and down erratically during your drive. 🎬 Watch how a new thermostat fixes an inconsistent temperature gauge.
- No Cabin Heat: If the engine isn't getting hot enough, there won't be enough heat transferred to the heater core for your climate control system.
Choosing the Right Aftermarket Thermostat
For the classic Saab 900, the quality of the thermostat matters. While many aftermarket options exist, owner experiences suggest that not all are created equal. OEM thermostats are often recommended for their reliability.
Aftermarket Brand Quality Tiers
| Tier | Brands | Notes |
|---|---|---|
| Recommended | Genuine Saab, OES (Calorstat, Wahler) | OEM and original equipment suppliers offer the best fit and reliability. The price is often comparable to premium aftermarket options. |
| Acceptable | Gates, Beck Arnley | Gates is a generally respected brand. Beck Arnley often re-packages parts from various sources, which can sometimes be the OEM part. However, be aware that both brands have been known to re-box lower-quality parts from other manufacturers. |
| Use with Caution | Motorad | Reviews are mixed, with some owners reporting premature failures. Motorad is a large manufacturer that supplies many other brands, so quality can be inconsistent. |
| Avoid | Professional Parts Sweden (PPS) | There is a strong consensus in the Saab community to avoid this brand for critical components due to widespread reports of poor quality, incorrect fitment, and parts failing out of the box. |
Pro Tip: 82°C vs. 89°C Thermostat?
Saab offered two temperature ratings: 82°C (180°F) and 89°C (192°F). Some mechanics recommend the cooler 82°C thermostat to provide an extra margin of safety against overheating, especially in warmer climates. However, using a cooler thermostat can sometimes lead to slightly increased fuel consumption as the engine's computer may enrich the fuel mixture. For most stock applications, the 89°C thermostat is appropriate.
Estimated Replacement Costs
The cost to replace a thermostat can vary based on whether you do it yourself or have a shop perform the work. The part itself is inexpensive.
| Part/Service | Estimated Cost |
|---|---|
| New Aftermarket Thermostat | $12.49 - $28.02 |
| New OEM/OES Thermostat | $18 - $30 |
| Shop Labor | $96 - $141 |
| Total Professional Replacement | $110 - $170 (approx.) |
Frequently Asked Questions (FAQ)
Is replacing the thermostat on a Saab 900 a good DIY job?
Yes, for most home mechanics, this is a very manageable job that takes about an hour. It requires basic hand tools. The thermostat is located where the upper radiator hose connects to the engine. On 16-valve models, you will need to move the idle air control (AIC) valve out of the way to access the two bolts on the thermostat housing. Be sure to have a pan to catch spilled coolant.
🎬 See this step-by-step walkthrough for replacing your 900's thermostat.Do I need to replace the gasket too?
Absolutely. Never reuse the old thermostat housing gasket. Most new thermostats come in a kit with the required rubber gasket or O-ring. Ensure the mating surfaces on the engine and the housing are clean before installing the new gasket and thermostat.
What is the little pin on the thermostat for?
That small pin or 'jiggle pin' is a bleed valve that allows trapped air to escape the system. It is critical to install the thermostat with this pin positioned at the very top (12 o'clock position). This helps prevent air pockets in the cooling system, which can cause overheating issues.
What other parts should I inspect or replace at the same time?
Since you will be draining some coolant, it's the perfect time to inspect your coolant hoses, especially the upper radiator hose and the small bypass hose underneath it on 16V models. If the hoses feel brittle, soft, or look swollen, they should be replaced to prevent a future breakdown. It is also a good time to check the condition and level of your coolant.
Helpful Videos
Technical Specifications
OEM Part Numbers: 30577561 8817298 9194242 8817538
Available in 82°C (180°F) and 89°C (192°F) opening temperatures. Includes a rubber gasket/seal and a small air bleed valve (jiggle pin). Located in a housing where the upper radiator hose connects to the engine block.
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.
- Saab 900: