Buy 20W-50 Engine Oil

20W-50 is the oil of the classics: engines with wide bearing clearances, no particulate filter, no longlife interval - and a design built around a thick oil film. On anything from the nineties onwards it is almost always the wrong choice.

Which vehicle?

Enter your vehicle - we show only what belongs in it.

More products

Why old engines like thick oil

An engine from the sixties or seventies has wider manufacturing tolerances and larger bearing clearances than a current one. The oil film has to fill those gaps, and a thin modern oil does not: it runs off, the pressure drops, consumption rises. That is exactly what 20W-50 is made for.

Then there is the sealing technology. Classics often have felt and cork gaskets, older-style shaft seals and no crankcase ventilation by today's standards. A thicker oil stays where it belongs.

Typical vehicles:

classics and modern classics with carburettors or early fuel injection
air-cooled engines that reach high oil temperatures in use
very high-mileage engines where oil consumption on a thin oil becomes unacceptable
historic motorcycles and stationary engines where the manufacturer specifies it

Cold starts and the seasons

20W means this oil is stiff in frost. Below roughly -10 °C, starting puts the starter motor, the battery and the bearings under strain, because oil pressure builds too late. In practice 20W-50 is therefore a summer and shoulder-season oil for cars that are laid up over winter anyway - which is true of most classics.

If you use your car all year round, check whether the manufacturer names a thinner grade for winter, or consider a 10W-40, provided the engine's clearances allow it.

Mineral or semi-synthetic

Mineral and semi-synthetic oils are the rule in this grade, and that is not backwardness but intent: fully synthetic oils with modern additive packages are not always the better choice for a classic. Two points are rightly debated in classic-car circles - the level of zinc and phosphorus compounds (ZDDP), which older camshafts and tappets depend on, and compatibility with old sealing materials.

If there is a specialist or an owners' club with a clear oil recommendation for your car, follow it: with historic engines, documented experience carries more weight than any general grade specification.

A new oil filter belongs with the change, assuming the engine has one at all: some pre-war and early post-war engines have only a gauze strainer instead of a filter, which is cleaned rather than replaced.

Frequently asked questions

Is 20W-50 suitable for my 2005 car?

Very probably not. Engines of that era are designed for 5W-30 or 5W-40, often with a longlife requirement and a particulate filter. 20W-50 is too stiff there and carries too much ash into the exhaust. The owner's manual is what counts.

Does 20W-50 help against oil consumption?

On an old engine with wide clearances, often yes - that is the actual purpose of the grade. On a modern engine it treats a symptom and creates new problems, because hydraulic components and the oil pump are designed for thinner oil.

Can I run 20W-50 in winter?

Possible, but not advisable: below roughly -10 °C oil pressure takes too long to build, and the cold start stresses the engine more than a whole summer of driving. For a car used all year round, ask for an approved thinner grade.

Why do classic owners talk about ZDDP?

Zinc and phosphorus compounds form a protective layer on heavily loaded sliding surfaces such as the camshaft and tappets. Modern passenger car oils contain less of them, because these substances load the catalytic converter - a point that falls away on a car without one, but still matters to its camshaft.