What to look for

Buyers Guide

Triumph Stag




The most rust-prone areas are the wheel arches, the sill-to-floor joints and the rear spring top mountings. Generally, ensure that drain-holes are kept clear and also clean the underbody regularly to ensure that dirt does not collect – particularly wheel arches.


Change engine oil and oil filter every three months or 3,000 miles, whichever occurs first. Flush the whole cooling system (including radiator) once a year, under pressure if possible. The whole system should then be filled with at least a 30% solution of a good anti-freeze, suitable for engines with aluminium cylinder heads. This solution should be kept in the cooling system even during the summer. Any toppingup should be done with a solution of similar strength. The timing chains should be replaced every 25,000 miles, or sooner if a noticeable rattle occurs, usually on starting or at idle. Check the petrol pipes in the engine compartment for chafing or cracking, especially where they are hidden by the air cleaner canister. Also ensure that none of the connections are loose, including where the pipes fit onto the two carburettors. It is a good idea to fit screw-type clips over these two latter connections. If the brake warning light starts to illuminate when the engine is idling this may indicate low oil pressure (the oil pressure warning light will only be visible under dark conditions, this being due to the way the system is wired up). However it is normal for the brake light to illuminate with ignition on but engine not running, thus providing a check on the bulb. It is possible that the oil pressure switch on the engine may be faulty, or the problem may be internal (perhaps even due to too low an oil level). It is suggested that an oil pressure gauge be fitted, this being a far more accurate and reliable method of spotting trouble, and even arresting it before it goes too far in some cases. Oil and water levels should be checked weekly. Any sign of water in the oil on the dipstick (noticeable perhaps not as water but as a light-coloured liquid – where the oil and water have mixed) should be investigated immediately. Also any sign of overheating on the water temperature gauge should be checked at once.

. . . and for the more mechanically minded

The main problems with the engine ‘boil’ down to two things: the timing chains and the cooling system. The chains stretch with use and the spring-loaded tensioners can only take up so much of the slack. If the chains become too loose they may ‘jump’ sprockets and upset the valve timing, the valves then striking the pistons with expensive results. The safe life of the chains (standard) tensioners, and guides, is around 25,000 miles when properly installed. The cooling system, in tip-top condition, is only just adequate for the engine. With use, the engine and radiator waterways will start to block up if a suitable additive for aluminium engines (this normally being contained in good anti-freeze) is not used. Also the cylinder heads will tend to corrode thus causing further blockage of the cooling system. In extreme cases the corrosion will cause water leaks from the cylinder head, and perhaps even allow combustion gases to enter the cooling system. With this, and/or fouling-up of the waterways and/or loss of water, the engine will tend to run too hot causing moving parts to wear out sooner than they should, and also the cylinder head gaskets may blow. Provided there are no inherent problems, cooling may be assisted (for those hot summer days) by fitting an electric fan as an extra. On all but the earliest cars, the special ‘double acting’ thermostat must always be fitted. The differential has a breather fitted at the top right-hand side towards the rear. Ensure that this is not blocked, otherwise the oil in the unit, when hot, will tend to relieve its pressure by blowing out through the oil seals.