Mercedes-Benz E-Class Alternator: Specs, Fitment & Common Faults
A genuinely alarming, honest account: a battery warning light on related models has been initially quoted at around £420 for a full alternator replacement, but the actual cause was a seized tensioner pulley bearing.
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OEM Part Number: A0009063003 (genuine alternator — confirm via VIN) — aftermarket alternators Bosch 0 986 081 850 / Valeo 439895
| Alternators (aftermarket) | Bosch 0 986 081 850 (175 A, freewheel pulley, 6 ribs, 52.5 mm, remanufactured exchange, plug PL166, core charge £23.51, excludes vacuum pump); Bosch 1 986 A01 045 (130 A, freewheel pulley, 6 ribs, 52.5 mm, new, plug 125, excludes vacuum pump); Valeo 439895 (200 A, 7 ribs, 51 mm, new original); Valeo 439999 (250 A, 6 ribs, 55 mm, new original); Valeo 440771 (250 A, rigid V-ribbed pulley, 5 ribs, 53 mm, remanufactured exchange, core charge £50.24); Hella 8EL 015 630-831 (175 A, rigid V-ribbed pulley, 6 ribs, 52 mm, new); AS-PL A3606S (250 A, 7 ribs, 50 mm, new, plug PL_2306); AS-PL A3762S (200 A, 5 ribs, 52 mm, new, plug PL_2306). |
|---|---|
| Outputs & variants | Outputs span 130 A to 250 A with rib counts of 5, 6 and 7: 200 A seven-rib 50-51 mm units (Valeo 439895 pattern) for the M274 2.0 petrol, 250 A units for the OM654 2.0 and OM656 3.0 diesels, and 200 A five-rib 52 mm units (Valeo 439991 pattern) for other variants; the EQ Boost 48 V mild hybrids use a belt starter-generator and are not covered. |
| Genuine (OE) numbers quoted | EG20U011 (AS-PL A3762S); CG25S035 (AS-PL A3606S); 439991 (AS-PL A3669(VALEO)); 439895 (AS-PL A3363(VALEO) and Valeo 439895); FG18T162 (AS-PL A3575S); CG25S043 (AS-PL A3878S); CG25S049 (AS-PL A3875S). |
| Fitment notes | With three rib counts and five outputs in play, the W213 must be matched by the Valeo or Mercedes OE number on the old unit rather than by engine alone; exchange units carry core charges of £22-£50, and BV PSH "Selected Reman" and "Pro Reman" units are remanufactured despite being listed as new. |
Mercedes-Benz E-Class Alternator: Often Blamed on the Battery Instead
On the Mercedes-Benz E-Class, it's genuinely hard to tell a weak battery from a failing alternator just from symptoms — both produce dim lights, slow starts, and a battery that won't hold charge. That's exactly why so many people end up replacing the wrong part, then returning to the garage a few weeks later.
Mercedes-Benz E-Class Alternator: What It Does
Running the Mercedes-Benz E-Class's electrical systems and keeping the battery charged while the engine turns over — that's the alternator's role. A properly functioning one means the battery only really needs to worry about starting the car and absorbing occasional spikes in demand.
Mercedes-Benz E-Class Alternator: Watch: Replacing It
Generation not stated in title; no W213 video found in 3 searches
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A Genuinely Alarming, Honest Real Account Worth Knowing — Mercedes-Benz E-Class Alternator
If the battery warning light has come on, this is genuinely worth knowing before paying for a full alternator replacement: a battery warning light on related models has, in documented cases, been initially quoted at around £420 fully fitted for a complete alternator replacement, but the actual root cause turned out to be a seized tensioner pulley bearing rather than a genuine alternator failure. Once this bearing loses its lubrication, the drive belt begins sliding and eventually destroys itself, stopping the alternator being driven entirely and triggering the same warning light, even though the alternator itself is completely fine.
It's also genuinely worth knowing that the pulley driving the alternator on many of these engines is a genuine one-way clutch mechanism, allowing the alternator's rotor to coast down gently to a stop rather than being abruptly halted.
Mercedes-Benz E-Class Alternator: Warning Signs, DIY Difficulty & Aftermarket Advice
These are the same regardless of make or model — see our full Alternator Guide for symptoms to watch for (plus a genuinely useful two-minute test to confirm it's not the battery instead), confirming the right amperage and fitment against your VIN, and which brands are worth trusting.
More Mercedes-Benz Alternator
The same part, covered across other Mercedes-Benz models.