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.
1988 Mercedes Benz 560SLFACTORY OEM SERVICE PROCEDURE
Gasoline System Testing: THERMOVALVE
- If vacuum does not drop to 10 in. Hg, disconnect vacuum lines from thermovalve. Connect vacuum tester to angular connector of thermovalve and apply vacuum. If coolant temperature is above (50°C) valve should be open. If coolant temperature is below (50°C) valve should be closed. Replace thermovalve if not operating correctly.
- If valve is operating, check for leaks. Disconnect both vacuum lines from thermovalve. Seal the straight connection and apply vacuum to angular connection. If vacuum is retained valve is okay. If valve will not hold vacuum, replace valve.
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.