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CLASSIC CAR OIL AND LUBRICATION FAQ

1. Is oil quality important?

2. Is the best oil an old formulation?

3. Can I use a current 10w40 formulation?

4. What are the merits of detergent vs. non detergent oil?

5. Can I use multigrade in my rebuilt engine?

6. With a quality classic oil, can I leave it in the engine for longer?

7. What can I do to counter the effects of ethanol in modern fuel?

Take a few minutes to read the Oil FAQ for modern cars, some of these are also relevant to Classics.

Is the quality of oil really that important in a car that only does a low annual mileage?

A combination of lower fuel RON and increased use of bio-ethanol, plus increased congestion, means classic engines  depend on the quality of their oil more than ever before.
It is vital that engine oil stays in viscosity throughout a broad temperature range and holds soot and combustion by-products in suspension throughout the oil’s life. Only top quality base oils and additives can offer sufficient levels of protection.

I’ve always thought that the best oil is the one that was designed for the car when it was new. Is that not the case?

Advances in oil technology mean that the performance of modern oils far exceeds that of oils from only 20 years ago.
Engine oil has a complex job to do, and we are learning more about this subject every year. Surely it therefore makes sense to take advantage of all this research, rather than trusting out-dated technology?

OK, so could I use a current 10w40 – will that be OK?

The one original oil specification that you should adhere to is the viscosity. A modern 10w40 multigrade is quite a lot thinner, both when hot and when cold, than say a 20w50. A thinner oil could well cause wear in the valve train, especially when the engine is fully warmed through. A slightly lower cold number (ie a 15w50) could however be beneficial at start up.
Prior to the 1960s, most engines ran on monogrades. Here again, adherence to the OE specification is important, especially if the engine is largely original.

I have a vintage car which uses a non-detergent oil. Surely I’d be better to change to an oil with detergent, to keep it clean?

Be careful here - vintage engines from earlier than about 1930 run with poor or no oil filtration, and dirt is designed to be deposited by the oil on ledges and castings within the block, where it can do no further harm. A detergent oil will dissolve these deposits back into the oil stream with potentially disastrous results. Only use a detergent oil in a freshly rebuilt engine, and change it frequently.

So could I use a multigrade oil in my rebuilt vintage engine?

Again, care is needed here, but in principle such a change could be beneficial, as it removes the need for summer and winter grades, and provides better protection at start up. However, just to be clear, a multigrade must only be used in a freshly rebuilt or cleaned out engine. If in doubt, contact an advice line such the one operated by Millers Oils.

If I use a top quality classic oil, can I leave a longer interval between changes?

To an extent this is true. However, you need to bear in mind that many classic vehicles spend the winter off the road, and it is always far better to lay up a car with fresh oil in the sump – there’s no fuel or condensate in the new oil which might otherwise attack alloys or start corrosion. If your car is to remain unused for more than three months, we’d advise you to change the oil.

What can I do to counter the effects of ethanol in modern fuel?

Modern petrol contains ethanol and all signs are that the level will increase in the future. Ethanol can cause corrosion in some metal parts used in older cars. The FHBVC have conducted tests on our VSPe Power Plus, VSPe and EPS fuel additives and in April 2012 endorsed them as offering protection against the corrosion effects of ethanol. This should reassure drivers that their classic cars can continue to run on modern fuels. View full details.