Myths About Motor Oil And Your Car

alastairq

Much will also depend on the oil capacity of the engine, size of filter, etc?

What about any thoughts on simply changing the oil filter frequently, but retaining the oil itself for longer?

[Given that filters can be small, also very cheap?]


The above idea generated by the fact that, on the railways, diesel engines don't have their oil changed at all.

But they do have massive filtration systems, and oil samples are sent for analysis frequently.

Which made me think [given carmakers propensity for taking the cheaper option] maybe filter changes at frequent intervals could be more beneficial?

TrickyWicky

Thats a fair point actually about changing the filters instead of the oil. My neighbours used to empty out the oil, do their engine work and then put the same oil back in again with a new filter lol.

To be fair, if the filter is changed and the junk in the oil is filtered out then it's quite plausible that oil changes could be a lot less

Joe_Horner

The important part is definitely the filter change. Modern oils will keep within acceptable specs through a lot of use and abuse. But the engine will still create contaminants (carbon, metal particles and so on) which will clog a filter in time.

The real problems come when the filter gets clogged to the point that its bypass opens. At that point there's a (slight) extra delay in supplying oil on startup and, when it does flow, it's carrying unfiltered oil straight to the bearings.

A._Badger

Joe_Horner wrote: »

The important part is definitely the filter change. Modern oils will keep within acceptable specs through a lot of use and abuse. But the engine will still create contaminants (carbon, metal particles and so on) which will clog a filter in time.

The real problems come when the filter gets clogged to the point that its bypass opens. At that point there's a (slight) extra delay in supplying oil on startup and, when it does flow, it's carrying unfiltered oil straight to the bearings.

Yes, and there is a major (largely unrecognised) issue about the quality of filters, too. Not all oil filters are created equal. There used to be (probably still is) an excellent website examination of a range of oil filters which were bought, dismantled and examined. All were claimed to be for the same application but the differences between them - and thus their effectiveness - were quite extreme.

It's best to stick to the vehicle manufacturer's filter unless you know what you are doing - not to buy the cheapest from the local car parts shed.

colino

On a money saving site I think there needs to be a bit of balance on the frequency of oil changes. We've came a long way from every car running 20/50 (and the real petrol heads with their stinking Castrol R) and if you have the manufacturers recommended gloop in the sump and you don't have any mechanical faults (Mazda diesels are a great example), 10-12000 miles and up to a year is a good yardstick. Modern, engineered lubricants wont have "worn out", their characteristics will be within tolerance and the grubby bits will still be in suspension. Modern fully synthetics don't damage seals anymore, its more likely that old, worn out engines are so far out of tolerance, their seals couldn't contain any fresh lube oil.
Filters are king, but why change them more frequently than necessary? They actually improve slightly with age as they begin retaining particulates and, before they start diminishing oil flow, give the circulating oil a harder job in flowing through the element. Again, I wouldn't have one for more than 10-12000 miles or a year, though some Corsa drivers think they are a fitted for life component.

iolanthe07

When I bought a Morris Minor in 1965 the handbook advice was an oil change every 3,000 miles. How things have changed! You could buy the oil by the quart in draught form from a pump. It cost peanuts, and changing the oil and filter was a ten minute job.

jimjames

colino wrote: »

On a money saving site I think there needs to be a bit of balance on the frequency of oil changes.

Whilst I agree there needs to be balance, as a Moneysaving site it is a false economy to skip services if it means your engine or turbo fails as a result. Horrific to see posts stating no service for 4 years and the potential damage that could be there for a buyer.

Nodding_Donkey

Stoke wrote: »

Nowadays, you should all be using synthetic, even if your handbook says semi synthetic. Find out the modern synthetic alternative and start using it.

Not for all cars

oldagetraveller

Stoke needs to re-educate the largest car manufacturer in the world about using only synthetic oil then!?

Stoke

Well, maybe I'm wrong but I've just switched to using synthetic on the advice on VW who altered their specs (my car is 14 years old) and it's running better than ever.