MG Mgb Service Costs & Schedule (2026) — What You'll Actually Pay

MG Mgb service: key facts

Oil service every 3,000 miles or 6 months
Gearbox oil: £70–£100 — don't skip this one
4 generations from 1962 to 1980
6 tracked service items across routine, major, and periodic schedules

Routine service items

These are the items covered in a standard service. Most garages include oil, oil filter and a basic inspection. The rest are typically checked or replaced on a schedule.

Service item	Interval	Typical cost
Engine oil and filter Classic car specialists recommend 3,000-mile intervals with modern multigrade oil (20W-50). MkI, MkII, MkIII, MkIV	3,000 miles or 6 months	£80–£120
Differential oil Use SAE 90 EP gear oil. Capacity approximately 2.5 pints. Check level annually. Wire-wheel cars have different final drive ratios and may need different oil specifications. MkI, MkII, MkIII, MkIV	36,000 miles or 3 years	£60–£90

Major service items

These are the big-ticket items. Miss them and you risk engine or gearbox damage. The costs are higher but the consequences of skipping are much worse.

Service item	Interval	Typical cost
Gearbox oil Use SAE 20W-50 engine oil or dedicated gear oil EP90. MkI, MkII, MkIII, MkIV	36,000 miles or 3 years	£70–£100

Periodic maintenance

Items that don't need doing at every service but should be on your radar at the right mileage or age.

Service item	Interval	Typical cost
Twin SU carburettor balance and tune Twin SU carburettors require regular balancing for smooth running. MkI, MkII, MkIII, MkIV	6,000 miles or 1 year	£120–£180
Spark plugs Use NGK BP6ES or Champion N9Y. Gap to 0.025 inches. Check and clean every 6,000 miles. Modern unleaded fuel may cause slightly different wear patterns than period leaded fuel. MkI, MkII, MkIII, MkIV	12,000 miles or 1 year	£60–£90
Brake fluid Use DOT 4 brake fluid. System holds approximately 1 pint. Bleed all four wheels in sequence. Critical for drum brake systems which are less tolerant of moisture contamination than modern disc systems. MkI, MkII, MkIII, MkIV	2 years	£80–£120

Known issues to watch for

The most common problems reported on the MG Mgb, ranked by severity.

dangerous

Extensive body corrosion

The MGB monocoque construction uses thin steel panels that corrode extensively in the British climate.

major

Overdrive unit failure

The Laycock de Normanville Type A overdrive unit fitted to many MGBs operates hydraulically using engine oil pressure.

minor

Lucas electrical system failures

MGB electrical systems use Lucas components including the notorious positive-earth charging system (pre-1967) and various switches, relays, and wiring looms of variable quality.

minor

Twin SU carburettor imbalance and wear

All MGBs use twin SU carburettors (HS4 or HIF types depending on year) that require regular balancing to maintain smooth running.

1 more known issues tracked. Check a specific MG Mgb's service records — a missed service on one of these issues could mean an expensive surprise.

Buying a used MG Mgb? Check its service history first.

A Mgb with a patchy service history can cost you thousands in missed timing belts, skipped oil changes, and hidden neglect. We pull the franchised dealer records — every visit, every stamp, every mileage reading — so you can see exactly what's been done and what's been skipped.

£6.99 · No records found = full refund, zero risk

MG Mgb service FAQs

How often does a MG Mgb need servicing?

A MG Mgb needs servicing every 3,000 miles or 6 months, whichever comes first. Classic car specialists recommend 3,000-mile intervals with modern multigrade oil (20W-50).

What does a MG Mgb service cost?

Costs vary depending on the service items required and whether you use an independent garage or main dealer. Independent garages are typically 30 to 50% cheaper for the same work.

Is a MG Mgb expensive to maintain?

Routine servicing starts from £80 at an independent garage, which is about average for this class of car. The bigger costs come from periodic items like timing belts, brake fluid changes, and transmission servicing. Keeping on top of the schedule avoids expensive failures.

How do I check a MG Mgb's service history?

You can check any MG Mgb's official dealer service records online using just the registration number. The check retrieves every logged dealer visit, including dates, mileage, and work done, so you can see whether the schedule has been followed or if there are gaps. It costs £6.99 and you get a full refund if no records are found.

MG Mgb Service Costs & Schedule