Servicing
Servicing your Triumph Stag — a basic home-service guide
A basic service is well within the reach of a careful home mechanic, and the Triumph V8 has a few quirks — alloy heads, timing chains, and a cooling system that must be kept healthy — that make regular servicing especially worthwhile.
Service intervals (indicative)
Indicative only — the handbook is the reference.
- Weekly / before a run: check engine oil and coolant (cold) and tyres. Watch the coolant especially — the alloy-head/iron-block V8 is unforgiving of neglected coolant.
- Every 3,000 miles / annually: engine oil & filter (frequent changes protect the timing chains); check/clean or renew spark plugs; renew the air-filter element; check/top up gearbox and differential oil; check driveshaft/UJ condition; check ignition timing and the Strombergs.
- Every 2 years: renew the coolant with the correct inhibitor (see the coolant-flush guide — critical on the Stag); renew the brake fluid; renew the gearbox and differential oil.
The tasks
- Engine oil & filter →
20W/50, ~5 litres with the spin-on filter — the single cheapest thing you can do for the V8.
- Spark plugs →
Eight NGK BP5ES, gapped 0.025" (0.6 mm), fitted cold into alloy heads.
- Gearbox oil →
EP80W-90 or 20W-50 for manual/overdrive; Type F ATF for original BW35/65 automatics.
- Rear-axle oil →
EP hypoid oil (EP80W-90 or EP90), 2 pints (1.14 litres) — filled to the level plug.
- Air filter →
A disposable paper element — renewed, not washed or oiled.
Also part of a full service
- Coolant — flush & corrosion protection →
- Brakes — bleeding & overhaul →
- Ignition timing →
- Carburettors — balancing the Strombergs →
- Cooling-system health →
Chassis greasing: the Stag needs far less routine greasing than older classics; check the workshop manual for the few propshaft and driveshaft points.
Tools & consumables
Trolley jack and axle stands, wheel chocks, drain pans, AF/Unified spanners, spark-plug socket, feeler gauges, torque wrench; 20W/50 oil, spin-on oil filter, paper air element, eight spark plugs, EP80W-90 gear oil (or 20W-50), ATF if automatic, coolant with the correct inhibitor, brake fluid, new washers.
This is a general guide and not a substitute for the official Workshop Manual. Confirm all figures, torques and capacities against the manual for your car and market.