How Often to change the Oil

longest to leave it is yearly, 6 monthly is a nice interval for most users, but it all depends on the vehicle, the use and the mileage per year.

The proper interval for a *service*, not just an oil and filter change, is what it says in the instruction book is appropriate for your vehicle beause, you see, different vehicles with different engines and drivetrains vary as to how much servicing they need. Rule of thumb, go by the book.

Huw

What does the manual say?

Take the advice given in the hand/service book and follow that. Depending on oil spec it might be 5000 miles or 15000 - and depends on how the car is driven. 40k is probably pushing it with even the best oils and best driving conditions. 9k is fairly normal. So use the spec of oil the maker recommends and stick to their change intervals. And also take note of early oil change intervals - not dependant on mileage - if the car is used for short journeys. Ie some will say change at one or two year intervals regardless of mileage. The car makers know more about what their products require than anyone here.

Mine are every 20kish or 2 years. The manual says 20k, the dash thing that tells me when it's due apparantly compensates for how hard it's driven/conditions etc - it's looking like it'll be about 16/17k for my first pukka service.

My guess is that you have either a VAG car or a Vauxhall. I further guess that it has a petrol engine.

Huw

206, 1.6 16v. Still, you got the petrol bit right :)

I learn something new every day. I didn't know Peugeot had gone to those service intervals nor that they had service monitoring equipment fitted.

Huw

Take it to National Tyres everytime they run a £10 oil and filter promotion. You can never change oil too many times.

Don't be daft. There is no significant advantage to changing oil more often than needed and a significant risk that more harmful contamination is introduced during the change by grease monkeys than are removed. Let alone for the potential for negligent accidents like improper filter changes and stripped sump plugs. Give me a car with 20,000 mile service intervals any day.

Huw

Huw (hedydd[nospam]@tiscali.co.uk) gurgled happily, sounding much like they were saying :

What technology changes do you think have been introduced to double or triple the oil life, let alone the inspection interval of other components?

Very few. The interval is stretched primarily to keep costs down for fleet managers.

Oh God here we go!

The cars are more expensive to produce but yes they are sold as having lower lifetime costs. Some fleets actually run cars to very high mileages so it is important that total running costs, including a long reliable life are optimised. I know of Vauxhalls [without the very latest technology and running on the official

20,000 mile intervals, that does local calls, similar to a postal drop van in a country area, that exceeded 200,000 miles before the door frames failed and an Audi Allroad which also exceeded 200,000 miles with services every 20,000 miles if it was lucky. It was sold because of the cost associated with an automatic gearbox issue. The engine ran like a watch despite being hammered from new.

Engines are built to finer tollerances with harder materials [hence the need to run-in fairly hard to prevent glased bores]. Better sealing piston rings. Cleaner fuel. The remaoval of sulphur has made a huge difference. Better oils, mainly specific oils suitable for very long service intervals which also contain very high detergency and dipspersants. Then we have the filtration. This has changed substantially. Most now use those new diposable element jobbings that are changed from the top and have quite a fine element combined with greatly increased capacity for the size of engine. There are many other fine design points that have changed as well which vary with the manufacturer.

The main feature that interacts with the driver is the computerised oil and driving condition monitoring devices. These things measure the number of cold starts, the driving style, the average coolant and oil temperature, the ambient temperature, the oil level and the oil condition, either by opacity or conductivity then use an alogarithm to calculate the optimum time for the oil change. So even though a theoretic 30,000 miles is possible for an Audi diesel engine in optimum condition, such as long motorway drives, in practice the oil change interval could be much lower than this.

These things are so clever that once, when I changed the oil in my Mercedes at about 6000 miles early [according to the monitor] without resetting the thing, the damned thing started actually extending the period to the next service of its own accord. It actually counted the 'wrong' way for a while and added some 5000 miles to the next oil change over a fortnight.

And before you ask what happens if it fails, it fails safe. If any sensor or monitor malfunctions the service warning comes on immediately. Also for low annual use either the time limit [usually two years] flashes a service due light or in the case of VAG cars there is an alternative 10,000 mile/one year fixed interval regime which the driver can opt for using cheaper oil and with the technology effectively switched off.

Are those enough changes or are you still not satisfied?

Huw

Never. It's too cold to be lying on your back on the drive.

Oh? What are most bores and piston rings made of nowadays, then?

Harder alloys and better cast than before. The ring packs are a science unto themselves and there is intense competition among manufacturers of these things to improve profiles and performance. Some even go for extremely hard CGCI for blocks which is especially costly to machine.

I have no idea why people question these things. The information is in the public domain and it is a fact that engines and cars in general are more reliable and last longer than ever before even though service intervals have expanded significantly. Very significantly indeed in new model launches where they have the opportunity of incorporating the latest advances.

These technologies are not new though. It has even trickled down to the common man's vehicle for a while now. Vauxhall had fixed services of 20,000 miles for about five years now I believe. Someone is sure to confirm or deny it. Perhaps both LOL.

Huw

Huw

Huw (hedydd[nospam]@tiscali.co.uk) gurgled happily, sounding much like they were saying :

Is that why the current Astra has 10k for the petrol, but 20k for the diseasel?

Besides, I think that's a case of "exactly"...

There is no such thing as a running in period on modern cars.

They're no different.

Because, unlike you it appears, we don;t believe marketspeak written by people who can't even find a dipstick.

And I wonder how much of that is down to improved lubricants...

What are these?

What are they made of?

And what's that?