How important are oil changes for diesel cars? And does it matter whether you use full or part synthetic oil? I've always owned petrol cars in the past and have changed the oil once or twice a year, but noticing little difference.
When I changed the oil on my Focus diesel at the garage (it was very black) the engine sounded smoother afterwards and start up was less erratic. Apart from lubricating the moving parts inside, what else does the oil do. Can it actually improve performance and economy, and does it clean the engine somehow? And is it necessary to change the filter each time the oil is changed.
The garage didnt drain the oil completely and put back on the sump plug when it was still trickling. I usually pour a bit of new oil in and let that drain for about 15 minutes. So, I may change the oil again in about a month and then do 2 yearly changes after that.
If you intend on keeping the car for hundreds of thousands of miles regular changes will help you achieve this.
Use the oil as recommended by the handbook. Oil technology is moving on and service intervals are becoming longer, but only if the corerct oil is used.
Oil in diesel will be black very quickly as the oil removes soot particles formed as a result of combusiton.
Change the filter each time as change intervals are now 10,000+ miles - what's an extra £5 or so? When intervals were 5,000 the filter was often only changed every other oil change.
Don't worry about any surplus - the majority was changed and follow what the handbook says. From another post you mentioned a Focus TDi which will have 10,000 or 12,000 change intervals - change more often if you want.
Owning a similar car/engine as you - mines the 1.4 TDCi - the service interval is 10,000 miles. Changing the oil more regularly will do no harm at all as the cleaner the oil the more smoothly it will run. Any longer and you run risk of causing damage to the engine.
Yes you do need to change the filter every time too - they are only paper inside and get clogged over the 10k. As long as you use a good quality oil at the correct viscosity (is that the right word?)- 5W-30 for mine - no problems. Ford recommend Castrol - it even says 'for Ford engines' on it. It sounds like the garage were doing a quick job on your car - I'd even stick some STP in or similar and let it drain like you mentioned.
Anyway changing the oil is an important part of maintaning the engine and longevity of your car. Every 5k on your/our engine would be excellent but 10k is fine.
On top of the good advice so far, two things to remember:
Oil doesn't just lubricate, it's an integral part of carrying heat away from moving parts Oil additives degrade over time, so lubrication and cooling is reduced even if particle build-up isn't too bad
So, change your oil (and filter) as often as you can afford, never leave it longer than recommended time or mileage wise.
You can save money by doing it yourself between services that you may want stamping officially at the required intervals. That way, your service history is complete, the in-between oil change is dirt cheap and your engine should last longer and run more economically.
If you look in any manual it will say, for example, 'change every 9,000 miles or yearly, whichever comes first '.
Problem is, the small print will ALWAYS say ' if, however, the car is used mainly on short journeys, or in dusty or extreme conditions, the oil and filter should be changed more frequently'.
I have still never found a manual which explains HOW frequently that means!
You can be pretty sure the car makers are asking you to change the oil way, way before it breaks down. They will always play safe.
But if you do regular six monthly changes, no matter the mileage, your car will thank you for it.
You will be flushing the sump with good oil and replacing it with good oil. Nice circle.
The problems start when condensation and impurities become too much for the oil. As it is pumped, it cleans - hence the blackness.
Many, many Danish drivers would use their cars a little in our awful winters, then check the oil level before the long trip through Germany to the warm south in June. The level would show perfect, full up.
By the time they hit the autobahn the engine would blow up.
That 'correct' level was only so due to water in the oil. A long run burns it off......low oil left!
So, a decent long run weekly and six monthly changes, you'll be laughing!
Thanks for the advice. I always make changing the oil a priority, especially now I am running a diesel engine which seems to benefit greater from more regular oil changes.
Originally posted by FiatPuntoOwner: Thanks for the advice. I always make changing the oil a priority, especially now I am running a diesel engine which seems to benefit greater from more regular oil changes.
I would agrue that there is no difference between oil changes in a diesel to a petrol - in fact, diesel fuel is a lubricant, unlike petrol, and as such tends to protect the engine more. After over 12 years of diesel ownership I have noticed that I very rarely have to top up the oil in the diesel cars I have owned, compared with the petrol cars!
Basically, follow the manufacturs advice, you do not need to change oil any more frequently than they say unless you are driving in extreme conditions (just as you would if you were driving petrols!) - diesel engines are more robust than petrols to start with! If you are in the UK and change oil more that the manufacturer recommends you are wasting your money.
this is only sound advice..if you use solely those oils recommended by the manufacturer.
should you wish to use any other oil, or a cheaper version, then reducing the service interval by, for example half or more, is recommended.
It is oil technology rather than sheer manufacturing technology that dictates service intervals...same with plug manufacturers.
volumne of oil in sump is also relevant...the less an engine has to work with, the more often that oil needs changing.
as stated before, local conditions, type of usage, etc also affect service intervals..just because oil does not SEEM to be used doesn't mean the oil is ok...diesel oil is high in detergent content...combustion pressures are higher...if trying to make an engine last, then more frequent service intervals are not wasted.
of course, a lot of motorists nowadays aren't worried if the car's engine isn't going to last long, as the car will have long since passed on to another hapless soul.
those intent on minimalist motoring...true eco warriors all...who recycle rather than splash out...are well advised to change engine oils frequently....as wll as gearbox and final drive oils...
another aspect, especially with an engine of advancing mileage, is the question of emmissions. Since crankcase fumes are recycled through, usually, the induction system, the condition of the oil has an effect....cleaner oil reducing the adverse emmissions a lot.
yet another issue raised by the threader's first post, is the use of synthetic or semi-synthetic oils. these tend to be more robust oils, requiring fewer changes...but unless the synthetic is used from new, there can be problems changing over. If buying used, taking the word of the previous owner, if you see them, isn't a good idea....synthetic oil taking over from non-synthetic oil is a tedious process of renewal and flushing, as the two dont like each other....
Yes, QJ, I had assumed that the owner would have the sense to put in the type of oil that the manufacturer reccomends - as far as I am concerned if you are a skinflint when it comes to buying oil then you deserve all you get!
Most modern diesels and I suspect most modern high performance petrol cars use synthetic or semi synthetics these days, but I would stand by what I said, unless you are using the car in extreme conditions (and that could meen stop start commuting every day!) then you may as well stick to the manufactureres recomended intervals, anything else is not necessary.
Originally posted by b308: Yes, QJ, I had assumed that the owner would have the sense to put in the type of oil that the manufacturer reccomends - as far as I am concerned if you are a skinflint when it comes to buying oil then you deserve all you get!
Most modern diesels and I suspect most modern high performance petrol cars use synthetic or semi synthetics these days, but I would stand by what I said, unless you are using the car in extreme conditions (and that could meen stop start commuting every day!) then you may as well stick to the manufactureres recomended intervals, anything else is not necessary.
have to agree, it's pointless these days to change oil outwith service intervals in modern cars - some cars even use higher quality oil to greatly extend normal intervals & they seem to run ok. I would consider changing to frequently a waste of oil & environmentally unsound
-------------------------------------------- Two junior particle physicists were dismissed today after using the Large Hadron Collider to smash conkers into each other at near-light speed.
The oil is the lifeblood of any engine and on a diesel quickly soots up. So more often=longer engine life depends how long you want to keep it? Just get Kwikfit or similar to do it not a main dealer as they will rip you off for £150-£200 for a (full service)which is little more than oil/filter and check it still has four wheels But some makers (Merc) are getting crafty now to tie you in to them ie no sump plug no drain plug or dipstick on autobox etc
Originally posted by barky: I would consider changing to frequently a waste of oil & environmentally unsound
That's open to debate. After all, it is in the interests of the manufacturers to extend the oil change interval to be as long as possible to make the car more attractive to fleet buyers etc.
Therefore, to make the engine last it may well be beneficial to change the oil more frequently than advised. After all, the extracting of the raw materials, transport thereof and construction of a new car is a lot more wasteful than adding a few extra oil changes over a course of a few years.
The other aspect is that most manufacturers couldn't care less if the engine dies prematurely, as long as it makes it past the first 60,000 miles for the warranty...
How long before someone annouces the first 60,000 mile oil change interval? Remember oils and their detergents haven't moved on that much, but oil change intervals have advanced massively. Hmmm.
In the U.S. they still consider 3,000 - 5,000 mile oil change intervals to be the safest, using the same oils we do. Are they so wrong when we're pushing up to 30,000 miles for some cars now?
I agree with the above post. The environmental benefits of prolonging the life of a car should far outweigh the cost of the oil. I change the oil more often than the manufacturers recommended interval of once a year (twice) for the purpose of keeping the engine in good condition, therefore prolonging the engine life.
Im usually environmentally conscious and know you should dipose of used oil at a local facility but I pour it back into the old tub or plastic bottles and dispose of it in the wheeley bin with the house waste. Is this acceptable? I know you definitely should not pour it down any drains.
Originally posted by FiatPuntoOwner: I pour it back into the old tub or plastic bottles and dispose of it in the wheeley bin with the house waste. Is this acceptable? I know you definitely should not pour it down any drains.
No!!! That's illegal, take it back to your local council tip, they almost always have free oil recyling...
Otherwise, the oil could enter the ground water at the landfill.
Also, if you put the oil into recyling it can be used again as lubricants etc.
Originally posted by finlo: The oil is the lifeblood of any engine and on a diesel quickly soots up. So more often=longer engine life depends how long you want to keep it? Just get Kwikfit or similar to do it not a main dealer as they will rip you off for £150-£200 for a (full service)which is little more than oil/filter and check it still has four wheels But some makers (Merc) are getting crafty now to tie you in to them ie no sump plug no drain plug or dipstick on autobox etc
I see where you are coming from but diesel fuel is a lubricant and therefore better for the engine than petrol fuel. Manufacturers recommend service intervals based on their research and they would hardly recommend intervals so long that they endangered the life of the engine, they would have to pick up the bill if they did!
On that basis i see know reason to change oil more frequently than they advise, subject to:
1. Use the correct oil (for my engine its 505.01 spec, not your cheapo 20/50!)
and
2. If you are using the car in harsher than average environment take their advise and change it more often.
Originally posted by finlo: The oil is the lifeblood of any engine and on a diesel quickly soots up. So more often=longer engine life depends how long you want to keep it? Just get Kwikfit or similar to do it not a main dealer as they will rip you off for £150-£200 for a (full service)which is little more than oil/filter and check it still has four wheels But some makers (Merc) are getting crafty now to tie you in to them ie no sump plug no drain plug or dipstick on autobox etc
I see where you are coming from but diesel fuel is a lubricant and therefore better for the engine than petrol fuel. Manufacturers recommend service intervals based on their research and they would hardly recommend intervals so long that they endangered the life of the engine, they would have to pick up the bill if they did!
On that basis i see know reason to change oil more frequently than they advise, subject to:
1. Use the correct oil (for my engine its 505.01 spec, not your cheapo 20/50!)
and
2. If you are using the car in harsher than average environment take their advise and change it more often.
It may well have lubicating properties but which part of the engine does it get to lubricate? (apart from the fuel pump)
Originally posted by finlo: It may well have lubicating properties but which part of the engine does it get to lubricate? (apart from the fuel pump)
Theres one bit for a start! The insides of the cylinders is another quite major part.
Just re-reading one of the above posts, it mentions that as long as it lasts 60k then its out of warranty - many manufacturer have unlimited mileage without that restriction and even when you have passed that milegage, if something went wrong you could sue the engine maker if you have followed the service recomendations (as I believe people have).
Originally posted by finlo: It may well have lubicating properties but which part of the engine does it get to lubricate? (apart from the fuel pump)
Theres one bit for a start! The insides of the cylinders is another quite major part.
Just re-reading one of the above posts, it mentions that as long as it lasts 60k then its out of warranty - many manufacturer have unlimited mileage without that restriction and even when you have passed that milegage, if something went wrong you could sue the engine maker if you have followed the service recomendations (as I believe people have).
Ok i was going to include upper cylinders, but it doesn't do a lot for crank/cams etc and burnt derv leaves behind some pretty nasty stuff! PS i'm sure iv'e seen a Cadillac ad proclaiming 100k service interval
Originally posted by finlo: Ok i was going to include upper cylinders, but it doesn't do a lot for crank/cams etc and burnt derv leaves behind some pretty nasty stuff! PS i'm sure iv'e seen a Cadillac ad proclaiming 100k service interval
I think we'll see long ones coming in more and more, many new cars have "variable" service intervals up to 30K. Oil technology and better engine technoloy is making more reliable cars - I can remember when I first bought cars in the 70s having to do 2/3K oil changes - one that had 6K changes were great when they first came - how things move on!
My 535d had variable service intervals. One little known fact is that changing the oil before the scheduled first service actually harms the engine! It's best to leave the original oil in, topped up if necessary, until the proper mileage is done. (Source, BMW Motorsport, Germany).
But some makers (Merc) are getting crafty now to tie you in to them ie no sump plug no drain plug or dipstick on autobox etc 
