Six-cylinder R107s (280SL/300SL territory with M110/M103 depending on market/year) are real cars — often overlooked beside V8 noise. Power, markets, and parts realities differ.
Related: engines explained, models by year.
M110 and M103
Know which six you are looking at by year/market. Characteristics and service items differ; do not parts-bin across them blindly.
Years, power, markets
Availability varies by market; US V8 dominance means sixes can be less common locally. Power is modest versus big V8s — that can be a feature for smoother touring.
Worth considering?
Yes, if the metal is sound and you want six-cylinder manners. Price and inspect like any R107: rust, fueling, docs. Scarcity talk does not excuse rot.
Common mistakes
Skipping labeling before disconnects, trusting verbal history without invoices, forcing stuck fasteners until they snap, and treating a different-year forum photo as a parts catalog.
When to stop DIY
Stop when the lift, hoist, or specialty tool you need is missing — or when the first approach did not change the symptom. Paying for diagnosis once beats buying the wrong assembly twice.
Practical takeaway
Drive one before you assume only a V8 will do.
Shop notes and paperwork
Keep invoices, part numbers, and dated photos before and after work. Future you — and any buyer — will ask what was actually done.
Safety
Use rated stands and hoists, relieve fuel/coolant pressure before opening systems, and disconnect the battery when the procedure calls for it. If a step needs a tool you do not own, rent it or hire it.
Verify against the factory manual for your engine and chassis. No invented personal car details here — use your plates, invoices, and measured symptoms.
Owner checklist before you start
- Confirm the exact chassis/engine so parts and torque specs match
- Stage tools, containers, and labels before the first bolt turns
- Plan a cold and hot verification after the work, not only a driveway idle
- Budget a contingency for seized fasteners and one missing specialty clip
If this topic intersects fuel, rust, or safety systems, fix leak and safety paths before cosmetic items. That order saves money twice.
