Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1987 Alfa Romeo Spider GraduateFACTORY OEM SERVICE PROCEDURE
THERMO Time Switch
Remove electrical connector from switch. Measure resistance as indicated in resistance table. If any resistance value is not to specification, replace switch.
THERMO TIME SWITCH RESISTANCE
| Temperature: °F (°C) | Terminals | Ohms |
|---|---|---|
| Below 86 (30) | G & Ground | 25-40 |
| Below 86 (30) | W & Ground | 0 |
| Below 86 (30) | G & W | 25-40 |
| Above 104 (40) | G & Ground | 50-80 |
| Above 104 (40) | W & Ground | 100-160 |
| Above 104 (40) | G & W | 50-80 |
- Warm engine to normal operating temperature and stop engine. Using a thermometer, measure temperature of coolant. Disconnect negative battery cable and sensor electrical connector.
- Connect ohmmeter leads to both terminals of sensor. Readings should be as specified for corresponding temperatures. See COOLANT TEMPERATURE SENSOR RESISTANCE table. If not, replace coolant temperature sensor.
COOLANT TEMPERATURE SENSOR RESISTANCE
| Temperature °F (°C) | Resistance (Ohms) |
|---|---|
| 68 (20) | 2100-2900 |
| 122 (50) | 700-1000 |
| 176 (80) | 250-400 |
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.