Safe Speed Forums

A few months ago on another board, I witnessed what became a heated debate regarding the recommended oil change/service interval on modern cars. The two sides of the debate divided into Europeans and Americans.

A couple of the American guys who owned old cars with legacy V8 engines designed in the 1960s or earlier swore blind that a 5000 mile oil change was absolutely essential, and that ALL cars should have a special "break in oil" for the first 1000 miles, whereas the Europeans contended that the manufacturer's recommendation for the oil change/service interval was governed by an onboard computer, and could be 18,000 miles or even more, particularly for diesel engines.

Admittedly, back in the 1970s, cars had a 3000 mile service interval. There would be an initial service at 1000 miles at which point the oil would be replaced. The "break in" oil was usually different from the "permanent" oil.

But times have changed. The American argument seemed to be that the extended oil change interval was a ploy by car makers to dupe owners into ruining their engines sooner, so that the car maker could sell more cars! A European countered this argument by pointing out that cars last much longer nowadays than the cars of 30-40 years ago, and also have much longer warranties, with 3 years/60,000 miles being commonplace these days, as opposed to 1 year/12,000 miles in the 1970s, and the days of the 3000 mile oil changes.

What do you gentlemen think? Do you go by the recommendations made in your vehicle owner's handbook, or do you take the stance that your engine needs an oil change at 5000 miles, regardless of anything your motor manufacturer says?

Lubrication technology and the advent of synthetic long life oil has transformed the oil change interval on modern cars. I do not believe that modern engines need an oil change after running in as they are bench run before installation in a lot of cars now. One of my cars actually required no running-in at all (for the engine).

Also, as synthetic oil is £10 per litre, I won't be changing mine unnecessarily.

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Malcolm W.
The views expressed in this post are personal opinions and do not represent the views of Safespeed.

More general chat than brainstorming I think. However..

I have one of the few cars that still has a break-in oil change at 1K, followed by subsequent changes at 10K. It also has a 60K warranty period. I follow the manufacturers change schedule precisely. Because:

a) It maintains the Warranty, which is void if the schedule is not followed.
b) I got a 3 year "free servicing" offer, so it doesn't cost me anything
c) The engine has an official "Performance Pack" which increases torque by 25%, without breaking the Warranty. The extra power pushes some of the engine components a little more towards their design limits (the higher powered variants have higher spec components), and I don't want to risk it.
d) If you have paid somebody else to do it then I don't want he hastle of getting my hands dirty, carefully collecting and then safely disposing of the old stuff. The high-grade oil recommended for a turbo 2L 265bhp engine is bloody expensive and I don't replace it for fun.

The trend in vehicle design is for even longer service intervals with some American cars now having 100,000 miles between changes as the engine can actually run for that long dry of both water and oil, but that is extreme.

I have just done a little research, and guess what? The Americans have fallen for spin again. At the time when 5K was recommended "Jiffy-lube" a chain that did for oil changes what "Kwik-fit do for tyres was running across America, and worked out that a few more percent customers per day added $$$$ to the bottom line, so noting how effective the words ", and repeat." had been with shampoo, they started a campaign that scared American motorists into changing their oil earlier. The campaign was taken up by others with similar interests (oil companies), and became embedded into the common psyche, to the extent that most "experts" still believe it. It is still advertising lies dressed up as expert opinion though.

A very wordy source that does cover it is here: http://www.trustmymechanic.com/motor-oil-bible.pdf, but you need to start at page 58 and go on, for quite a few pages.

If your service interval says a number, then that will be a very conservative number, and you can probably double it without problems. The only modern car that I know of that needs anything like a 5K oil change is a Mitsubishi EVO (5K oil change and tyre rotation), and that is also a very high performance 2L turbo. Only if the car is regularly used for track days should you need to go lower.

Yes. Modern engine design and materials selection, combined with high performance synthetic oils that don't break down as quickly as mineral oils mean 10,000 miles plus is no problem whatsoever. The only exceptions are diesel engines which tend to contaminate the oil with carbon more, thus benefitting from slightly shorter change intervals, and cars subjected to extreme operating conditions such as track days, where very high running temperatures shorten the oil life, and there is a possibility of contamination due to metal particles from increased engine wear.

As regards running in, as noted earlier most modern engines are "bench run" to start with, and the materials used are so hard wearing that many manufacturers recommend deliberately allowing the initial oil fill to contaminate a little to promote initial wear, so as to bed everything in. If you were to change the oil at 1000 miles you'd actually make things worse, as the cleaner oil would stop the planned "bedding in" wear and leave you with a car that still hasn't run in 20,000 miles later.

Modern engines truly are amazing; and it is barely an exaggeration when people describe cars with 50,000 miles on the clock as "just run in".

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I change my oil (semi-synth) about every 6k, and don't believe in any particulant 'additives' such as slick50 (PTFE) or molyslip (molybdenum disulfide)* as the engine oil, if of sufficiently high quality will do it's job just fine before you go pi$$ing about with the blend.

For all the cost of oil - which is much less than a tank of fuel (nearly £70 for me) I'd rather have, even if misguided, the assurance than my oil is in good condition, lubricating & cooling as it goes. Not some tarry gloop or runny ink that does next to nothing.

*I've only put those products into crappy old engines (Fiesta & Maestro) that were getting a bit rattly & they did quieten down for a wee while - so they work as repairs, but I'll be damned if I goop up my engine with burnt teflon!

They always used to say that changing the oil twice as often would double the life of the engine. I don't think it's any longer true, mainly because of very considerable advances in oils.

Aren't there american cars with 100,000 mile service intervals? Don't they run oil up to 100,000 miles these days in some vehicles?

I stick to manufacturer recommended service intervals myself.

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Paul Smith
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Some VW and Skoda diesels are now available with "variable servicing". The engine has an oil condition monitor in the sump which tells you when the oil needs a change. I recently drove a base model Skoda octavia diesel with about 25,000 miles on it and noticed to my horror, that the service book had never been stamped - not even for a first service! After speaking to them they assured me that it would put a light on the dash when it needed an oil change - probably at about 30-32000 depending on the running I was doing!

In the 60s, machining tolerances were nothing like as good as they are these days and engines had to be "run in" (whereby all the mating parts wore to accommodaye each other's surface irregularities). That's not really a problem on most mass-produced engines these days. Running in oil used to be pretty poor at lubricating to make this process happen faster.

As for more frequent oil changes, my car is 15 years old, It's engine is 16 years old. It has over 220,000 miles on it and has been (almost completely) immersed in salt water then left standing for 18 months. The engine is fine and the car is going to fall to bits long before the engine dies. What's the point in doubling the life of the engine????!!!!

My car does no great mileage, no more than about 10000 a year, I tend to just replace it yearly when the guy services it for me, it's more of an MOT service than a normal service though... Usually get it done a few weeks before I head to the test centre... There's stuff I can do myself, but it's nice to have a second opinion on this kind of thing, especially when you consider the MOT waiting lists over here at times...

I can't afford to get it serviced by Ford... Way too much for a poor student

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Mike

My car has an oil change when it gets serviced every 16000 miles or two years. I have to say, it isn't the best car in terms of service intervals on the market!

I also stick to recommended intervals now (given my low mileage it boils down to once a year). In the "old days" I used to chnage points/plugs/oil every 6 months, but agree things have moved on.

I know the North Star engine as used in many Cadillacs had a 100,000 mile interval for first service (they also claimed you could drive a fair distance with no water in the system and some distance with no oil!). The North Star V8 is otherwise quite unsophisticated

5000? the EVO engine requires a change EVERY 4500 miles

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I'd go along with that definately. I wonder what percentage of cars are scrapped because the engine has gone bang and what percentage are scrapped because the body or a combination of non engine related problem are uneconomical to fix? I suspect its much more the latter. I can be pretty sure the body on mine is going to be the death of it, unless I restore it, which I may do. The engine sounds and feels like its still got another 100k in it, although its currently only done 85000 varified miles.

Saying that I do change mine every 5k, but only because it would be a shame to ruin a perfectly good engine that could be used on another car or keep mine running for many more years. The recommended interval is 6k/6months but I don't do that many miles so I leave it a bit more then 6 months and wait until its done 5k, which is maybe only a month or two overdue.

At the moment modern engines on synthetic oils run to about 15,000 for oll and filter change. Plugs run at least 30K with some up to 100K

BUT

now manufacturers are using "duty cycle" to determine oil change intervals. This is based on by engine speed/number of revolutions, throttle opening etc. it is more representative of the work that the oil has done. The upshot is that the service indicator on the instrument pack may come on before the recommended hange point if it thinks the oil needs changing early. Modern BMWs use this method.

Remember....changing the oil filter is just as important ar changing the oil. If the filter gets clogged it bypasses the filter. Not good.

Also many manufacturers are going back to timing chains rather than belts to reduce service costs. Some cars built in the 80s and early 90s have a £1000 price tag for the timing belt change service (Fiat 5 cylinder engines for example).

On the flip side I have an American Vtwin engined motorcycle. Oil change every 2500 miles. Air cooled engines tend to knacker oil.

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I think part of the crucial part here is the definition of the word 'modern'. many new cars have relatively old-tech engines, while others have state of the art units. Is a 10yr old car modern?

My co. diesel mondeo has 12.5K service intervals, but my chimaera has 6000 miles intervals and had the 1000 mile running in service (with different oil) after the engine re-build.

I thought the 6000 mile interval on TVRs was the "engine rebuild interval"!

Only the ones with their own engines! The Chimaera has the Rover lump in it and they hang together pretty well if looked after.

2003 Vectra - 2 years or 20,000 miles

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