Mobile Alternator & Starter Motor Replacement Reading
The alternator charges the battery and powers the vehicle’s electrical systems while the engine runs. The starter motor cranks the engine on ignition. Both are replaceable by a mobile mechanic at your home or workplace.
Alternator Problems and Diagnosis
A failing alternator eventually drains the battery completely, leaving you stranded. Symptoms develop gradually:
- Battery warning light on dashboard (often the first sign)
- Dim or flickering headlights — particularly noticeable at low speeds or at idle
- Electrical malfunctions — infotainment cutting out, electric windows sluggish
- Battery keeps discharging — flat battery despite a healthy and recently replaced battery
- Whining or squealing noise — worn bearings inside the alternator body
We test the alternator charging output (should be 13.8–14.4V at idle, rising under load) and check for diode failure using our diagnostic equipment before recommending replacement.
Alternator Replacement Pricing
| Vehicle Category | Price (supply and fit) |
|---|---|
| Small to medium petrol | from £150 |
| Diesel (generally more complex) | from £180 |
| Premium brands (BMW, Audi, Mercedes) | from £220 |
Prices include a remanufactured alternator with a minimum 12-month warranty, all associated belts inspected, and electrical system test on completion.
Starter Motor Problems and Diagnosis
A failing starter motor makes itself known at the worst possible time — the moment you try to start the car.
- Single heavy clunk when turning the key — solenoid engaging but motor not spinning
- Grinding noise on startup — worn or jammed ring gear engagement
- Slow, weak cranking — starter motor drawing excessive current due to worn brushes
- No cranking at all — complete starter failure or open circuit
We test battery voltage, starter relay and the full starter circuit (voltage drop test) before condemning the starter motor.
Starter Motor Replacement Pricing
| Vehicle Category | Price (supply and fit) |
|---|---|
| Small to medium petrol | from £120 |
| Diesel | from £150 |
| Vans | from £160 |
Access varies significantly by vehicle — some starters are easily reached from the top of the engine; others require removal of the air box, battery or engine mounts. We confirm access difficulty before providing a final quote.
Combined Electrical System Check
When we attend for an alternator or starter fault we carry out a full charging system check: battery health, alternator output, voltage drop testing on all main cables and earth connections. Corroded earth cables are a common cause of unexplained electrical faults and charging problems that would otherwise lead to unnecessary component replacement.
Book a Visit
Call 07305 523333 or use the enquiry form. Tell us the make, model, year and the symptoms — we will give a guide price over the phone before booking. We cover all Reading postcodes and surrounding Berkshire towns.
Areas we cover
- Mobile mechanic in Reading
- Mobile mechanic in Wokingham
- Mobile mechanic in Newbury
- Mobile mechanic in Basingstoke
- Mobile mechanic in Bracknell
- Mobile mechanic in Tilehurst
- Mobile mechanic in Caversham
- Mobile mechanic in Earley
- Mobile mechanic in Woodley
- Mobile mechanic in Henley-on-Thames
- Mobile mechanic in Twyford
- Mobile mechanic in Thatcham
Frequently asked questions
How do I know if my alternator is failing? +
Signs of alternator failure include the battery warning light on the dashboard, dim or flickering headlights, electrical components cutting out, a whining noise from the engine bay, or a battery that keeps going flat despite being a new or healthy unit. We test the alternator output voltage to confirm.
What is the difference between a starter motor fault and a battery fault? +
A flat battery produces a rapid clicking sound or complete silence when you turn the key. A failing starter motor often produces a single heavy clunk, grinding, or the engine cranks very slowly even with a good battery. We test the battery and starter circuit before replacing components.
Can a starter motor be repaired rather than replaced? +
In some cases worn brushes or a faulty solenoid can be rebuilt. However, labour costs for a rebuild often approach or exceed the cost of a reconditioned replacement unit. We will advise the most cost-effective option after inspection.