Oil Change interval
Moderators: Doone, westonwarrior
Oil Change interval
It says in the owner?s manual that diesel engine oil should be changed every 5000km. Even for a total petrol head like me, this seems a bit on the eco unfriendly side. Do others replace the oil that often?
Terry
Terry
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- Supreme Being
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Engine oils absorb water vapour and oxygen which deteriorate the
lubricating qualities of the oil, especially when driven irregularly and
over short distances.
Diesal engines will last much longer if the oil is changed every three
thousand miles or 6 months whichever is sooner. An older engine will
not benefit from expensive synthetic oils, the correct grade old fashioned
mineral oils are far cheaper. If you change the oil regularly it's only
necessary to change the filter after say 8,000 miles.
Sorry about the environment, but making a new engine to replace one
that's been badly maintained would probably generate more noxious
gases than would otherwise be the case.


Engine oil has been discussed by knowledgable members of
this forum, on several previous occasions. Seek and you
shall find.
However, the general consensus is to stick to the Mazda
specifications which are:
SAE 5W - 30 changed at 5,000 kilometres, or 3,107 miles.
For worn engines there may be some benefit in changing
to SAE 10W - 40 or even 15W - 50. Using heavier grades
may slightly increase fuel consumption with engines that
have no need for it.
Synthetic oils can maintain their lubricating qualities
over longer periods and mileage, but this will almost
certainly increase the pollutants and carbon particles
in the oil which may increase the overall wear rate, it
can also result in blocking oil ways which will reduce
the oil flow rates unless the engine is flushed on a
regular basis.
If you want to run the engine to a great deal more than
80,000 miles then good engine maintenance is essential.

If people are worried about cost I would suggest they find their nearest engineering supplier, I'm a service engineer on excavators and without bulk discount I can buy 10-40 oil for ?32.90 for 25 litres which is 1.30 a litre. If people are concerned about the quality bear in mind that engines on plant machinery are run at high rev's for long periods of time and get little love or maintenance, generally far more abuse than a vehicle diesel engine. It's not often the engines let go either!
and yes the engines are modern and high tech with turbos. 


Last edited by ChrisEm on Fri Sep 01, 2006 11:32 am, edited 1 time in total.
Found this on car bibles web site! Hope it helps!
http://www.carbibles.com/engineoil_bible.html
Engine Oil Shelf Life.
I couldn't decide whether to put this in the FAQ or the main page, so it's in both, because I get asked this question a lot. Typically, the question is along the lines of "GenericAutoSuperStore are having a sale on WickedlySlippy Brand synthetic oil. If I buy it now, how long can I keep if before I use it?"
In general, liquid lubricants (ie. oils, not greases) will remain intact for a number of years. The main factor affecting the life of the oil is the storage condition for the products. Exposure to extreme temperature changes, and moisture will reduce the shelf life of the lubricants. ie. don't leave in the sun with the lid off. Best to keep them sealed and unopened.
Technically, engine oils have shelf lives of four to five years. However, as years pass, unused engine oils can become obsolete and fail to meet the technical requirements of current engines. The specs get updated regularly based on new scientific testing procedures and engine requirements. But this is only really a concern if you've bought a brand new car but have engine oil you bought for the previous car. An oil that is a number of years old might not be formulated to meet the requirements set for your newer engine.
If your unopened containers of engine oil are more than three years old, read the labels to make sure they meet the latest industry standards. If they do meet the current standards, you might want to take the extra precaution of obtaining oil analysis before using them. An oil analysis will check for key properties of the oil and ensure that it still meets the original manufacturing specs. Of course the cost of getting an analysis done on old oil is probably going to outweigh going and buying fresh stuff. So it's a double-edged sword.
As a general rule, the simpler the oil formulation, the longer the shelf life. The following is a guideline under protected conditions:
Product Shelf Life
Base Oils, Process Oils 3 years
Hydraulic Oils, Compressor Oils, General Purpose Lubricating Oils 2 years
Engine Oils and Transmission Oils 3 years
Industrial and Automotive Gear Oils 2 years
Metal Working and Cutting Oils 1 year
The following are signs of storage instability in a lubricant:
Settling out of the additives as a gel or sticky liquid
Floc or haze
Precipitates/solid material
Colour change or haziness
Water contamination in a lubricant can be detected by a "milky" appearance of the product.
http://www.carbibles.com/engineoil_bible.html
Engine Oil Shelf Life.
I couldn't decide whether to put this in the FAQ or the main page, so it's in both, because I get asked this question a lot. Typically, the question is along the lines of "GenericAutoSuperStore are having a sale on WickedlySlippy Brand synthetic oil. If I buy it now, how long can I keep if before I use it?"
In general, liquid lubricants (ie. oils, not greases) will remain intact for a number of years. The main factor affecting the life of the oil is the storage condition for the products. Exposure to extreme temperature changes, and moisture will reduce the shelf life of the lubricants. ie. don't leave in the sun with the lid off. Best to keep them sealed and unopened.
Technically, engine oils have shelf lives of four to five years. However, as years pass, unused engine oils can become obsolete and fail to meet the technical requirements of current engines. The specs get updated regularly based on new scientific testing procedures and engine requirements. But this is only really a concern if you've bought a brand new car but have engine oil you bought for the previous car. An oil that is a number of years old might not be formulated to meet the requirements set for your newer engine.
If your unopened containers of engine oil are more than three years old, read the labels to make sure they meet the latest industry standards. If they do meet the current standards, you might want to take the extra precaution of obtaining oil analysis before using them. An oil analysis will check for key properties of the oil and ensure that it still meets the original manufacturing specs. Of course the cost of getting an analysis done on old oil is probably going to outweigh going and buying fresh stuff. So it's a double-edged sword.
As a general rule, the simpler the oil formulation, the longer the shelf life. The following is a guideline under protected conditions:
Product Shelf Life
Base Oils, Process Oils 3 years
Hydraulic Oils, Compressor Oils, General Purpose Lubricating Oils 2 years
Engine Oils and Transmission Oils 3 years
Industrial and Automotive Gear Oils 2 years
Metal Working and Cutting Oils 1 year
The following are signs of storage instability in a lubricant:
Settling out of the additives as a gel or sticky liquid
Floc or haze
Precipitates/solid material
Colour change or haziness
Water contamination in a lubricant can be detected by a "milky" appearance of the product.
Well, I'm here and reading with interest but ChrisEm seems to have it covered.
I would basically concur with his comments in as much that base oils cannot denigrate but the addidtive packages can fall out of suspension and of course go out of date. But if you buy a modern up to date (as far as API spec goes) oil it will always be in spec for a Bongo since the vast majority are 10 years old and there are none newer in the Uk than 5 years old.
I would basically concur with his comments in as much that base oils cannot denigrate but the addidtive packages can fall out of suspension and of course go out of date. But if you buy a modern up to date (as far as API spec goes) oil it will always be in spec for a Bongo since the vast majority are 10 years old and there are none newer in the Uk than 5 years old.