Cold Engine
- Ensure engine coolant is below 122°F (50°C). Disconnect vacuum hose No. 27. Attach vacuum gauge to vacuum hose at tubing manifold. Check for vacuum at idle speed. If vacuum is present, proceed to HOT ENGINE test.
- If there is no vacuum, disconnect other hose and check for vacuum. If vacuum is present, replace thermo valve C and retest. If there is no vacuum, check auxiliary intake vacuum hose for leaks or blockage.