Oil Change For Diesel Cars/trucks

[chuchok]

This is a reply that a friend of mine gave me about oil change etc.He has a fleet of rental cars and a third of them (4x4) are Diesel.Please note, that this advise is for NZ conditions.

Yes there is a big difference in mineral oil and synthethic oils. Mainly synthethic is used in high perfomace engines (sporting and race type) and it is generally twice the price!!.

In a diesel engine there is not alot of choice , some oils such as Shell helix have a grade that will do both diesel and petrol engines but it must be of a grade of SJ or higher ( we use this in our diesels).

But remember even the more expensive specailty oil ( diesel specific) must be changed at regular intervals 5000kms/4-6 months . While this seems a short service period bear in mind tha diesel engines create carbon soiling in the engine oil and this shortens the life of the oil and if not changed, the engine. You do not need a full service every 5000kms just a oil and filter change

Hope this helps a few people.

Edited March 1, 2005 by chuchok

[Khutan]

Thanks, an interestig post.

I thought you used a mineral Detergent Oil like Delo or Course to get the longer service life, particularly heavy trucks.

[Khun Jean]

This is one where people have different opinions for a long time.

I had a few diesel cars myself.

Never changed the oil, only topped it of. Regular change of oil filters every 30.000 km.

I drove more than 200.000 km in those cars before i sold them and when checked the engines were in very good condition.

I friend of mine had a courier company. He had a fleet of Volkswagen cars and Mercedes busses and trucks. Never changed the oil.

Cars should have a check every 5000 kms. Yeah right like every week. He did it twice a year. Oil filters every 3 months (40-50.000 km)

His maintenance costs dropped dramatically and no engine problems with any car.

Don't remember which oil was used. For my cars i just bought wathever brand was available and within the specs of the engine.

[taxexile]

different opinions indeed !

almost every mechanic i have ever spoken to has said that the single most important servicing job is the oil change.

the oil lubricates the moving parts in an engine and all the microscopic bits of metal that get worn away during use will be suspended in the oil and cause more and more wear as the oil becomes "less oily" and more contaminated.

the increased wear will lead to the engine running inefficiently , with valve clearances and piston tolerances way out of kilter , smoking exhausts , increased fuel consumption etc.etc.

i suppose the amount of wear will depend on the type of use (stop start versus long runs , and the temperature of the oil)

whilst an engine may continue to function with dirty oil , it will only be a matter of time before some of the oil channels get blocked with dirty gunk saturated oil and oil flow will slow down or stop altogether and the affected bit will heat up and cause the engine to fail.

similar to a blockage of the coronary arteries !!

oil changes are a cheap way of maintaining an engine in tip top condition .

[Bizz]

Every 5000k oil and filter.

[Khun Jean]

the oil lubricates the moving parts in an engine and all the microscopic bits of metal that get worn away during use will be suspended in the oil and cause more and more wear as the oil becomes "less oily" and more contaminated.[/quote

That is why you need to change the oil filter regularly. Also when an engine is brand new you do need to change the oil as the first oil is of a different substance and all the moving parts have to get worn in. After a few thousand kilometers it is not necessary to renew the oil only filters.

Most oils get better over time.

[Harmonica]

This is a reply that a friend of mine gave me about oil change etc.He has a fleet of rental cars and a third of them (4x4) are Diesel.Please note, that this advise is for NZ conditions.

Yes there is a big difference in mineral oil and synthethic oils. Mainly synthethic is used in high perfomace engines (sporting and race type) and it is generally twice the price!!.

In a diesel engine there is not alot of choice , some oils such as Shell helix have a grade that will do both diesel and petrol engines but it must be of a grade of SJ or higher ( we use this in our diesels).

But remember even the more expensive specailty oil ( diesel specific) must be changed at regular intervals 5000kms/4-6 months . While this seems a short service period bear in mind tha diesel engines create carbon soiling in the engine oil and this shortens the life of the oil and if not changed, the engine. You do not need a full service every 5000kms just a oil and filter change

Hope this helps a few people.

Certainly helps me. Thanks.

[COBBER]

This is one where people have different opinions for a long time.

I had a few diesel cars myself.

Never changed the oil, only topped it of. Regular change of oil filters every 30.000 km.

I drove more than 200.000 km in those cars before i sold them and when checked the engines were in very good condition.

I friend of mine had a courier company. He had a fleet of Volkswagen cars and Mercedes busses and trucks. Never changed the oil.

Cars should have a check every 5000 kms. Yeah right like every week. He did it twice a year. Oil filters every 3 months (40-50.000 km)

His maintenance costs dropped dramatically and no engine problems with any car.

Don't remember which oil was used. For my cars i just bought wathever brand was available and within the specs of the engine.

<{POST_SNAPBACK}>

With due respect Jean this sounds like advice straight out of a thai engine maintanance manual. Oil breaks down and loses its lubricating capacity.Had some experiance with fleets of taxis and indeed we did do oil changes weekly and many of these engines did over 1 million kms.

[Khun Jean]

Like i said. Different opinions AND experiences.

Most people are afraid to take the risk. But as in my friends case who had a courier company it saved a lot of money. Not only oil changes but not doing everything the car dealer says. Like every 5000-10000 km a small maintanence and checkup. Costs 150 Euro AND the car not available for at least half a day. These small checkups are like, air filter ok -> yes. Lights working -> yes, Tires ok -> yes, window wipers ok -> yes. Most if not all can be done yourself especially if you are using cars a lot. Never skip the important checkes like brakes, tyres, etc..

Not going to every maintenance/checkup:

26 weeks * 150 euro * 40 cars = 156.000 euro saved per year.

Not changing the oil every 5000 kilometers:

40 weeks * 20 * 40 = 32.000 euro saved per year.

With the saved money (188.000 euro per year!!) he could buy 8-10 new vans. So even when a few cars break down the savings are enormous. But in all the years not 1 car had an engine failure. When a car broke down it was caused by reckless driving or another kind of accident.

[jonik]

Not changing oil is the most stupid thing you can do cause it's the engings blood , old oil don't give the same lubing as new ones.And if there is a turbo mounted it's even more importent.Cause the turbo heat the oil pretty much and maby burn it making it useless.Also you save money on gaz changing more often.I'll think even you would run smoother on singha versus old homemade brew.

[Khun Jean]

Jonik, Jonik. How can you tell somebody is stupid when the facts prove it that you don't need to change the oil. Or do you think 40 cars used for 12-16 hours everyday is not a good test? As i said before this is a subject with very different opinions. I just tell you my experiences, no use to tell me i am stupid. I saved a lot of money on skipping small services, checkups and changing oil, which i did myself. Some people do everything a cardealer tells them. Some think and make decisions for themselves.

I suggest you do a google search and find some more information, instead of repeating your cardealer. He is only interested in making as much money as possible.

[taxexile]

After a few thousand kilometers it is not necessary to renew the oil only filters.

Most oils get better over time.

then why does the oil turn black after a few thousand kilos , and the experiences of a car rental company , who can write any losses off against tax , are not necessarily to be followed by a private owner who will have to pay for new pistons , crankshafts and valves out of his / her own pocket.

hot oil loses a lot of its properties over time and picks up all kinds of particles from the engine and the by products of combustion , the viscosity will change and the lubricating qualities will suffer. sludge will obstruct and eventually block the oilways and engine failure will occur.

car dealers are interested in making money but they also have the reputation of the brand to maintain and whereas checking lights and wipers might add to the labour costs of a service and be deemed as wasteful , oil changes are not.

what are your views on brake fluid changes ?

[Khun Jean]

All the things you mention are valid points if you are not using synthetic oils. Synthetic oils have a very high "flame" point so there is almost no influence from the heat an engines makes. As synthetic oils are very uniform there is no sludge. If you use a good airfilter, not a paper one these are not good, very little particles will end up in the oil. Same for the oil filter. If you use a good one it will filter out almost everything. If you use a cheap filter for the air intake and oilfilter you will end up with a lot of particles in your oil which will affect it greatly. Synthetics have additives to counter the by products of combustion. Synthetic oil sticks to metal better. This is important for the "cold" start. With other oils you have a big change you have metal to metal contact. This will damage your engine the most. When a car is used a lot, not standing idle for long times this will not happen with synthetic oils. So if you change the oil filters, air filters on time and top off the oil you should be fine. When i check the oil after 4-5000 kilometers it is not black but almost the same as if it was new. This is already a good indication the filters do their work and burning by the heat of the engine occured. Very easy check. If it is very black, change your oil. Preferably for another brand.

Again this is no theory of mine. I did it with 3 of my own cars and a friend with a courier company did it with his fleet of 40 cars. Why do you think i tell this. I will not sell you something, it is just something you can consider doing yourself. My experiences were good, and it saved me a lot of money. I have enough knowledge to change the windshield wipers, change the brakes, oilfilters, airfilters. These small tasks i did myself which saved me a lot again. The cars i mentioned were Audio 80 , Volkswagen Golf diesel, Mercedes Vito diesel.

With brakefluids i follow the car dealer, simply because i don't have specific knowledgde about that.

[Thetyim]

My experience is completely at odds with Khun Jean.

I run six vans for several years, part of a fleet of several hundred.

I had a MAINDEALER service done every 6000 miles.

The fleet manager came to congratulate me. My vans were numbers 1,2,4,5,8 and 14 as the cheapest cost per mile to run.

[Harmonica]

Chuchok, this is an excellent thread you started. Thanks!

[chuchok]

Like i said. Different opinions AND experiences.

Most people are afraid to take the risk. But as in my friends case who had a courier company it saved a lot of money. Not only oil changes but not doing everything the car dealer says. Like every 5000-10000 km a small maintanence and checkup. Costs 150 Euro AND the car not available for at least half a day. These small checkups are like, air filter ok -> yes. Lights working -> yes, Tires ok -> yes, window wipers ok -> yes. Most if not all can be done yourself especially if you are using cars a lot. Never skip the important checkes like brakes, tyres, etc..

Not going to every maintenance/checkup:

26 weeks * 150 euro * 40 cars = 156.000 euro saved per year.

Not changing the oil every 5000 kilometers:

40 weeks * 20 * 40 = 32.000 euro saved per year.

With the saved money (188.000 euro per year!!) he could buy 8-10 new vans. So even when a few cars break down the savings are enormous. But in all the years not 1 car had an engine failure. When a car broke down it was caused by reckless driving or another kind of accident.

<{POST_SNAPBACK}>

Kun Jean, you are giving an example about commercial vehicles that are being used all day.ie: not the normal go to work in the morning and then home at night.The car never really gets a chance to cool down.Ever wondered why taxis will always get better milage then the normal joe bloggs car...well that's the reason.Cold, hot,cold hot, etc.Much more strain on the engine.

The main point that my mate pointed out was that to change the oil and filter was NOT a service.Most people can do this by themselves.

I have another friend that has a medium sized mechanical business, mainly fixing your average punters car.He also gets overflow work from a large very upmarket European dealership...he does the tune ups/servicing.The dealership gave him a diagnostic computer to hook the cars up etc...all ihe uses it for is to reset the cars computer.for the full srvice all he does is 1)change the oil 2)Change the oil filter and 3)Change the spark plugs(unless they are 100000kms ones)You don't want to know how much the dealership charged for the service $$$$$

hamonica, no problem starting the thread..I also find it interesting.