🚗 Classic Fault — Mercedes-Benz R107/C107 (1971–1989)
W107 R107 chain-driven timing rust — idle fluctuation M110
💰 Estimated Repair Cost
$40 – $150 GBP
Parts and labour estimate
🔧 Tools Required
CIS pressure gauge set
📋 Overview
The M110 twin-cam engine in the 280SL suffers idle fluctuation from aged K-Jetronic components.
🩺 Symptoms
- Hunting idle
- rough cold idle that may clear when warm
- poor economy
- occasional stalling at junctions
🔍 Possible Causes
- Ageing K-Jetronic warm-up regulator
- control pressure out of spec
- dirty idle air valve
🛠️ Diagnosis Steps
Test control pressure with CIS gauge set. Clean idle air bypass with carb cleaner.
✅ Most Confirmed Fix
Warm-up regulator replacement and K-Jetronic service
81% of users confirm this fix worked (17 reports)
🔗 Other Mercedes-Benz R107/C107 Faults
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