Long oil change interval

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Citroenmad
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Post by Citroenmad »

You can get a decent A2 1.4 SE (make sure its the SE with air con) for around £3500, but mileage will be heading high. They do seem expensive i agree, however they do hold onto their money so you shouldnt lose much on one.

A-class is an ok car, watch out for rust through. They are a little cheaper but not as nicely made as the A2 and yes ive heard that about the ride too.

I suppose you have thought about the Picasso? For some reason i really like them, great cars in my opinion. A good one can be had very cheaply too. No bigger than a Xsara, good visability and a high driving position. Diesels are cracking too.

A2 is very classy and well built, but not bomb proof and VAGS can actually be dissapointingly unreliable too. So it pays to choose carefully.
HDI
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Post by HDI »

The most critical factor that determines oil and engine longevity is the oil specification advised by the vehicle manufacturer. They will have specific oils listed in the manual. These have been tested to meet the service intervals that are indicated in the handbook. Many manufacturers will now only honour warranties if the precise oil specified in the manual is used.
However , these intervals are for average use , they will also indicate intervals for extreme service , these intervals will be substantially less than the average interval. For example , if a 15K mile interval is for average use , then 7.5 or even 5K will be extreme service interval.
Extreme service is , very high temperature climate , very low temperature climate , very wet climate or worst of the lot , short journey , low mileage and stop start , this is THE engine killer !!
I know some people who drive 1.5 miles to work each way but still service their car on the average interval !!
Modern lubricants are amazing and combined with modern engines which do not pollute their engine oil because of very accurate fuel management , will protect engines for the extended intervals now in use.
Of course , if you are in any doubt that the engine is being properly protected for these extended service intervals , then change it more frequently ! To know for sure if this is necessary the only way is to have the oil analysed , this will show exactly what is happening inside the engine and may even show that even more extended intervals are possible !
Citroenmad
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Post by Citroenmad »

HDI wrote: Modern lubricants are amazing and combined with modern engines which do not pollute their engine oil because of very accurate fuel management , will protect engines for the extended intervals now in use.
Yes, however there are exceptions to that. Im not that technically minded myself, however i do under stand modern cars with FAp filters and no special fluid rely on extra fuel being injectoed to increase temperatures to allow the FAp to do its business. Im pretty sure this is what goes on with the 1.9 Vauxhalls and why they actually full up with fuel in the oil. WHich obviously is contaminating the the engine oil.

I agree though, a lot of people do seem to take the extended life service intervals fgor granted, regarless of what use their car is used for. As you say, short trips require more frequent oil changes etc.
JohnD
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Post by JohnD »

Citroenmad wrote:

modern cars with FAp filters and no special fluid rely on extra fuel being injectoed to increase temperatures to allow the FAp to do its business.

.
It seems that Mazda6 diesels are similar. They inject extra diesel to increase the temperature to clean the FAP. On engines doing only short journeys, most of the diesel ends up in the sump, raising the oil level until the engine runs away causing damage.
HDI
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Post by HDI »

Well , the post fuel injection used on systems without special fluid is only periodic , done to burn off soot particulate in the FAP filter. If the system is working correctly there should not be an accumulation of unburnt diesel in the sump.
If I had a FAP equipped vehicle I'd disable the stupid system , it's only a fop to environmental politics !! Also that FAP fluid is extortionately expensive !!
scratcher
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long oil change

Post by scratcher »

Hi, I always change my cars oil every 3000 miles that was always what Citroen recommended for their older models. My Xantia 19d (149000+miles) always passes the emmisions test first run! I saw a report done on lubricating oils in the early 60's and despite the additives most of them started to break down after 1000 miles. Besides I think most ordinaty lubricating oils are hydroscopic( there's a good word), that is why we have to pay so much for LHM as it not supposed to be.
tonupteabag
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Post by tonupteabag »

i ignore the recommended interval and change at 5000mls using good semi-synthetic as its not too expensive why worry if the oil that is drained is fairly clean? as the oil is the engines blood and if left can cause extensive damage its better to have good clean oil and confidence that your car is looked after as in time it will pay for itself but thats just my oppinion :)
HDI
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Re: long oil change

Post by HDI »

scratcher wrote:Hi, I always change my cars oil every 3000 miles that was always what Citroen recommended for their older models. My Xantia 19d (149000+miles) always passes the emmisions test first run! I saw a report done on lubricating oils in the early 60's and despite the additives most of them started to break down after 1000 miles. Besides I think most ordinaty lubricating oils are hydroscopic( there's a good word), that is why we have to pay so much for LHM as it not supposed to be.
That was the early days of multi-grade oils , things have moved on beyond belief !
Engine oils are not hygroscopic , in fact they are specifically designed to repel water and leave a boundary layer on metal , some are better than others at this.
The most important aspect of engine oils is the quality of base stock , the foundation of the oil , and TBN total base number , this is the ability of the oil to neutralise acid. Higher quality oils and full synthetics have a higher TBN number.
addo
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Post by addo »

Mentally going through cars I no longer own or have rebuilt extensively, two scrapped due to rust with still-OK motors, one replaced engine due to blowby (mileage unknown but massive), one hit trees, one cracked head, one blown head gasket (corrosion internally).

I'm somewhat attendant to oil change intervals, but reckon my "history" as sketched above surely isn't too unique. Ah well.
dnsey
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Post by dnsey »

That's a very good point, Addo!
How often these days do you come across engines with knocking big ends, burning enough oil to produce clouds of smoke etc?
Besides, if the worst happens, a cylinder hone, new rings, bearing shells etc will usually sort it. Sounds major, but it's usually a pretty straighforward 'engine left in' process - many of us used to do this sort of thing regularly, almost like a 'major service' is these days!
HDI
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Post by HDI »

Ask Toyota MR2 owners about big ends !! :wink:
Citroenmad
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Post by Citroenmad »

tonupteabag wrote:i ignore the recommended interval and change at 5000mls using good semi-synthetic as its not too expensive why worry if the oil that is drained is fairly clean? as the oil is the engines blood and if left can cause extensive damage its better to have good clean oil and confidence that your car is looked after as in time it will pay for itself but thats just my oppinion :)
Couldnt agree more, you would have to be a rather tight person not to spend a few quid on an oil change. Could well save you the hassle of engine problems in the future, maybe the car wouldnt give any problems anyway, though its looking after your car.
lexi
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Post by lexi »

The thing is that a diesel engine with oil anywhere in sump does not evapourate like petrol counterpart. Semi Synthetic means little in many cases on the cheaper brands. Nobody really knows what ratio of blends are being bought.

In fact semi synthetic on old school diesels is a waste of money for those who change oil religously. The newer engines are different as the tolerances and operation call for the viscoscity range that synthetic based oils give.
tonupteabag
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Post by tonupteabag »

lexi wrote:The thing is that a diesel engine with oil anywhere in sump does not evapourate like petrol counterpart. Semi Synthetic means little in many cases on the cheaper brands. Nobody really knows what ratio of blends are being bought.

In fact semi synthetic on old school diesels is a waste of money for those who change oil religously. The newer engines are different as the tolerances and operation call for the viscoscity range that synthetic based oils give.
true but i use my car on a lot of short journeys as well as the school run so as semi-synthetic isn't as expensive as its made out to be i prefer to use it and as when it comes time to change the oil its not past its best and i feel better knowing that if i do go over the interval i'm not killing my engine apart from that i end up using the old oil to spray under the car to stop the water sitting in odd areas
Julz
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Post by Julz »

addo wrote:Oil changing is overrated. Can we have a show of hands from people who have - in the last ten years - lost an engine or part thereof due to indisputable neglect of oil freshness?

I have seen first hand, failures due to underspec zinc content, but that is from the bottle - not oil ageing.

Cheers, Adam.
I used to have an Astr van that I inherited from my brother. It had done 165K when I got it but in 3 yrs only did about 12K as I used it just for DIY, without a oil change.
When I got a new job I started doing about 30K a year so had it serviced at 15K intervals. I sold it at about 210K as it had started to use quite a bit of water so I thought something "major" was due shortly. Not sure if this was related