🚗 Classic Fault — Mercedes-Benz W115 (1968–1976)
Intake manifold gasket air leak between carbs
💰 Estimated Repair Cost
$20 – $50 USD
Parts and labour estimate
🔧 Tools Required
Carb cleaner, torque wrench, socket set
📋 Overview
Air leaks at the intake manifold gaskets between the carburetor bases and the cylinder head are a frequent cause of unstable idle. The original paper gaskets deteriorate and allow unmetered air to enter downstream of the carburetors.
🩺 Symptoms
- High or fluctuating idle
- lean mixture
- hissing sound from intake area
- idle cannot be stabilized
🔍 Possible Causes
- Failed intake manifold gaskets
- warped carburetor base
- loose manifold nuts
🛠️ Diagnosis Steps
Spray carb cleaner around manifold base while engine idles. RPM rise confirms leak location.
✅ Most Confirmed Fix
Replace intake manifold gaskets. Torque nuts evenly to specification.
85% of users confirm this fix worked (38 reports)
🏷️ Parts Needed
M115 intake manifold gasket set
🔗 Other Mercedes-Benz W115 Faults
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