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Car engine oils

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eMeS

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Sorry not rail related, but I hope someone here knows the technology behind my query.

I'm retired, and I've driven a Vauxhall Astra (petrol) for many years - fairly low annual mileage.
One of the popular outlets for motor oils offers a variety of oils both basic and "more refined"... By "more refined" the label suggests that the oil is specifically for my Vauxhall brand engine, and that if I was driving a Peugeot, I'd be advised to use a different(?) oil carrying a "Peugeot" label. What I've noticed over the years is that if < I > do the oil change, and put in Vauxhall labelled oil, the engine oil warning light stays "off". OTOH, when I've had my car serviced at a garage, I find the oil warning lamp comes "on", and sometimes well before I'm due for the next service. Topping up with "Vauxhall" oil puts the oil warning lamp out.

How does my engine know what oil is in use? Am I being short changed by the garage?

Thanks for any insights!
 
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ajs

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As far as l know, the engine oil warning light comes on, when the oil level is low and needs toppIng up. If the oil light comes on you should check the oil level and top up otherwise you could do some serious damage to the engine. I have no idea if a more refined engine oil lasts longer than a cheaper variety but if it does, may explain why the oil light comes on sooner when a cheaper oil is used.
 

Bletchleyite

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Which oil warning light?

If it's the red one (oil pressure), stop your car immediately - as soon as that comes on your oil pressure is low enough that damage is already being caused. The yellow one (which some cars have and some don't) is a level warning.

Is it an old car? If so, sometimes you can get low oil pressure due to things having worn away, and using a thicker oil can help for this (typically cheaper!). However, don't just do this - check with a garage if it is appropriate to that car.

Other than in that sort of case you must use the specified oil grade for your car, doing otherwise can cause damage. The different brands have different additives which allegedly improve e.g. longevity of the car (not so much of the oil) but it's debatable if that's just marketing spin.
 

LSWR Cavalier

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One can understand things one can see being expensive because they look good, but paying several times more for oil? Not necessary

If the lamp comes on after changing, the oil might have settled/distributed, check the level when cold and top up if necessary

For an older vehicle I should be inclined to use cheap oil and change it a bit sooner than recommended
 

Domh245

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Like other posts have said, the oil light is indicative of oil pressure(/level), they won't have been able to develop a sensor that can differentiate between oils, and they certainly wouldn't have been fitting it to an astra! To me it sounds a bit like the garage is perhaps not topping the oil up to quite the same level on the dipstick (or some other means of short changing you in terms of oil fill) and that filling it up with any grade of oil is enough to put it back into a healthy amount.

As for the question of "more refined" oils, it is worth remembering the different markings on a label of oil. There's the viscosity measures (the Xw-XX number) which tells you how thick the oil is, and how it thins with temperature, but then there is also the 'standard' of the oil - usually this is the manufacturer specific one which will also claim compliance with an ACEA standard. This relates to 'fine tuning' of the oil where necessary, in more modern cars this involves using a low 'SAPS' oil to prevent it clogging the various exhaust filters but can also improving the thermal characteristics to prevent breakdown at higher temperatures.
 

LSWR Cavalier

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A well-known consumer magazine took a hundred vehicles to have their oil changed and checked them after
Several vehicles still had the old filter, a handful still had the old oil and the old filter
Changing the oil and filter is worth doing oneself, I used to make sure the engine was hot so the old oil flowed out, a garage might not do that
Paid my trusty mechanic to change the oil and filter once, fortunately I checked the filter before starting the engine, for he had not tightened it, could have made a mess on the road
 

eMeS

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Thanks for all your replies.
You've confirmed what I thought - that an Astra isn't clever enough to sense any special additives in "Vauxhall" branded oil! I noticed the problem when the car was quite young, around 30,000 miles and I think still on the oil as in it on s/h purchase, and after a 50 mile drive on "A" roads. I changed to Vauxhall branded oil, and didn't see the red oil warning lamp again, until I'd had the car serviced by a garage. No problems whatsoever if I have the car serviced (new oil filter etc, but I do the oil change myself, using Vauxhall branded synthetic oil).
On my first car I had the luxury of an oil pressure gauge, but that was a 3.4ltr Jaguar Mk VII.
 

thejuggler

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All you need is oil which matches the specification in the handbook. My car takes 0w20, fully synthetic, which isn't that common, but I can find it at reasonable prices. Quite handily the grade is stamped on the oil filler cap.

Not sure what oil light is. If its the low pressure warning you are killing the engine, check levels regularly and top up as required.

If its an 'oil change due' warning this is based on how the car is driven. Lots of short hops may reduce the mileage between changes.
 
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Sorry not rail related, but I hope someone here knows the technology behind my query.

I'm retired, and I've driven a Vauxhall Astra (petrol) for many years - fairly low annual mileage.
One of the popular outlets for motor oils offers a variety of oils both basic and "more refined"... By "more refined" the label suggests that the oil is specifically for my Vauxhall brand engine, and that if I was driving a Peugeot, I'd be advised to use a different(?) oil carrying a "Peugeot" label. What I've noticed over the years is that if < I > do the oil change, and put in Vauxhall labelled oil, the engine oil warning light stays "off". OTOH, when I've had my car serviced at a garage, I find the oil warning lamp comes "on", and sometimes well before I'm due for the next service. Topping up with "Vauxhall" oil puts the oil warning lamp out.

How does my engine know what oil is in use? Am I being short changed by the garage?

Thanks for any insights!

The oils you see recommended for Ford or Peugeot only really refer to diesel cars. All cars burn oil to a degree, and all diesel engines produce soot. In a modern diesel the soot is captured by a diesel particle filter and during this filtration it also captures some of the products of burning the lubricating oil. In Peugeot cars there is a fuel additive known as EOLYS fluid (sorry, I've never been able to find out what the acronym means) that deposits continuously in the filter, and when the car senses that the filter is blocking the system injects extra fuel to burn off the soot deposits as carbon dioxide. Unfortunately the ash produced by the combustion of the oil cannot be burnt off, so it slowly accumulates and eventually blocks the filter so it cannot regenerate.

So that is the problem. Car manufacturers have significantly reduced this problem by introducing Low SAPS oil. (low sulphur, phosphorus and sulphated ash). The exact specification depends on the manufacturer. It is important to use the correct oil.

NOTE. This does not apply to petrol cars or diesels not fitted with the particle filter, so it applies to most diesels since ~2005. However, some manufacturers may have used other technology to reduce soot in the exhaust, so the use of filters may not be universal in modern diesels.
 

Gloster

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I wonder if some garages just put enough oil in to reach the minimum level mark, but if the driver does it he or she is likely to play it safe and put a bit extra in.
 

eMeS

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I wonder if some garages just put enough oil in to reach the minimum level mark, but if the driver does it he or she is likely to play it safe and put a bit extra in.
I don't recall a "low" filling on the dipstick ever being a problem. In reply to others, the oil lamp which comes on is the "red" lamp. My 1.8ltr petrol Astra (Auto gearbox) is also fitted with an orange tinted Service Interval indicator, and the car is now 10 years old with ~60,000 miles recorded.
When the red oil warning lamp has come on, I normally stop as soon as possible, turn the engine off, check the oil level (I've always found it "OK") and then carry on with my journey. This resets the lamp to OFF. I can't recall the oil lamp coming on again on the second part of the journey, even if I then do several miles before getting home, and on some occasions under "hot and fast" conditions.
As said earlier, when I changed the engine oil with branded expensive oil, I had no red oil lamp warning whatsoever - until I let the garage do it as part of an annual service.
 

Mcr Warrior

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In Peugeot cars there is a fuel additive known as EOLYS fluid (sorry, I've never been able to find out what the acronym means) that deposits continuously in the filter, and when the car senses that the filter is blocking the system injects extra fuel to burn off the soot deposits as carbon dioxide.
Possibly it's a trade name rather than an acronym. Presumably only for use in diesel fuelled car engines, and quite expensive, like many other additives are?
 
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Possibly it's a trade name rather than an acronym. Presumably only for use in diesel fuelled car engines, and quite expensive, like many other additives are?

Expensive, and there are several variations. However, a pouch will last ~90,000 miles. I have a car with this system and it has done 125,000 on the original pouch. The issue is that the system on Citroen/Peugeot needs to be reset using a specific computer diagnostic system that the poch has been replaced, otherwise the warnings will continue.
 

cactustwirly

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Sorry not rail related, but I hope someone here knows the technology behind my query.

I'm retired, and I've driven a Vauxhall Astra (petrol) for many years - fairly low annual mileage.
One of the popular outlets for motor oils offers a variety of oils both basic and "more refined"... By "more refined" the label suggests that the oil is specifically for my Vauxhall brand engine, and that if I was driving a Peugeot, I'd be advised to use a different(?) oil carrying a "Peugeot" label. What I've noticed over the years is that if < I > do the oil change, and put in Vauxhall labelled oil, the engine oil warning light stays "off". OTOH, when I've had my car serviced at a garage, I find the oil warning lamp comes "on", and sometimes well before I'm due for the next service. Topping up with "Vauxhall" oil puts the oil warning lamp out.

How does my engine know what oil is in use? Am I being short changed by the garage?

Thanks for any insights!

Your car's manual should say a viscosity spec, which is normally 0/5/10W30/40/50 etc
You get different grades of oil, mainly semi-synthetic or fully synthetic. The latter is slighly more expensive but well worth using as it's of a higher quality.

@GRALISTAIR
Care to disclose more? Oil is soon black after changing, how can it last 10 000 miles and millions of transits? What happens to it if is not changed?

If it immediately goes black you've got engine issues!
Normally shoul be a brown colour.
 

thejuggler

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New oil in diesels will go back very quickly due to the combustion process which produces soot.

New oil in petrols should look new for many months after a change.
 

Snow1964

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Many cars have 16,000 or 20,000 mile intervals, although usually with a 1 year limit.

Most have 2 different servicing regimes, a choice of annual or long life.

If you only do short journeys, the engine will not be fully warmed up. More precisely the oil in the sump won’t be fully viscous, as it is colder. Effectively you may end up only circulating the same oil, with part never leaving the sump. As a rule of thumb need to be going at least 45 minutes (nearer an hour in cold weather) to fully circulate the oil.

When engines get old and worn, if seem to be using oil, then can try a slightly thicker grade. But obviously this will not circulate as easy so only sensible for an engine that needs to be kept going for now, but is not long for this world.
 

GRALISTAIR

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@GRALISTAIR
Care to disclose more? Oil is soon black after changing, how can it last 10 000 miles and millions of transits? What happens to it if is not changed?
Oil is cheap relatively but fully synthetic is more expensive. Semi-synthetic is as implied. Special polymers are dissolved in the oil. The trick is, in brutal cold climates you want the oil to be thin when cold so not too much strain is put on the engine when starting but as it gets to temperature you want the oil to thicken up so it sticks to the moving parts. Oxidation causes blackening and one of the metal oxides of iron is magnetite which is black. Rust which is haematite is red brown.
 

Domh245

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If that happened in a petrol I'd be concerned.

Modern petrols, with direct injection, are also susceptible to the same sort of soot formation issues as Diesels. Similarly if it's a turbo engine it's likely to discolour from the heat
 

LSWR Cavalier

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It starts a nice golden green colour, does not stay like that for long
And what about gear oil? I understand one should check the level but there is no need to change the oil
 

Domh245

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And what about gear oil? I understand one should check the level but there is no need to change the oil

Depends on the transmission. Some gearboxes (typically manuals) are 'sealed for life' and you should be able to get away without ever doing the oil on them, though obviously if you use it particularly harshly (track/performance use) or keep the car beyond what might be considered a normal life (100,000mi+) then it wouldn't hurt to change it. Automatic transmissions on the other hand do tend to require oil changes and top ups - if a car has a gearbox dipstick it's a good hint that'll need checking!
 

thejuggler

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Gearbox and diff oil changes every four years on my car. That's probably why 300,000 miles is quite possible with little more than the routine maintenance.

Sealed for life merely shortens the life of the gearbox. Its the modern way for manufacturers to fit components like filters buried in the engine which can't be replaced easily.

If they last for 10 years that's good enough for the manufacturer. Who will pay for a new engine on a 10 year old car even though the part which caused the engine failure costs pennies?
 
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