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A quick query - something I have long wondered about.

One of our farm vehicles - a ute, does a very small annual mileage, usually no more than 1000 km.

It's basically good running, not short or stop/start, as we keep it just for travelling into town on occasions to collect farm equipment and materials etc, a journey of about 50km.

I like to keep all our vehicles in good condition, so service them at appropriate intervals.

But I've wondered about oil and coolant changes with this vehicle. The franchise dealer says I should change the oil every 6 months, or 1 year at max, regardless of the mileage. They say this is because oil has a finite life in a vehicle.

When I do this, the "old" oil comes out still looking pristine and almost new, and I wonder if I'm just wasting money with such frequent changes.

In the days of "Motoring with Robbie", I got the impression that oil change periods should be related more to mileage, and type of running, rather than just time!

Do I really need to change the oil that often, if I'm doing such a small mileage?

Similarly with engine coolant. The dealer says that even with the longer life coolant, and no matter what mileage I do, I should change it every 2 years.

They say this is because it loses its anti-corrosive protective properties over time.

Again, I wonder if I'm just wasting money, or should I really keep changing the coolant so frequently?

Mike

From the "Ask Jack" archives - 14 December 2009

It's a good question and there will be many different opinions on the issue.

It's generally accepted that oil should not be left longer than twelve months regardless of distances travelled before changing.

There are many horror stories from those who've serviced and owned Japanese imports where servicing had been neglected, albeit for long periods. In worse case scenarios, engines have lost oil pressure or cam shafts have seized and broken due to engine sludge.

The big difference here is; with some of the Japanese imports it would appear nobody ever lifted the bonnet or bothered too carry out regular servicing, whereas you take the time to check levels and oil condition on a regular basis.

Oil can get diluted by fuel bypassing the piston rings over a period of time, which is normal, and is one reason it should be changed on a regular basis. Condensation can form in the engine as well and ends up being mixed with the oil which leads to a breakdown of the oil quality and the formation of sludge. Another factor could be where the vehicle is parked. If it is garaged it is much better than sitting outside in the cold winter months.

The problem with asking these sorts of questions is nobody wants to buy themselves into an argument if there was ever an engine problem which could be related to the oil condition.

It's your call I'm afraid Mike but if it helps, I wouldn't lose sleep if the servicing went slightly over the twelve month limit provided you use a good quality oil and one which has the recommended viscosity.

As far as the coolant goes; once again there are probably different opinions within the industry, here's mine.

Changing the coolant is rarely done properly in my opinion. This is not a criticism of garages or individuals, it is more based on the time required to drain and flush an entire cooling system properly which includes the heater and removal of the thermostat.

Many flushes involve the removal of a radiator or heater hose and letting the water drain out, maybe running a hose flush through the sytem, reconnecting the hoses and topping up with new inhibitor. In these cases there's still a certain amount of the old additive still sitting somewhere in the cooling system. So changing the coolant the 'easy' way every two years makes sense to me.

If you have long life coolant in the engine however, then you should't be required to replace it until the recommended time period has expired. There are some manufacturers who claim their coolant will last ten years or 200,000kms. If this is the case then leave it alone until that time has elapsed.

Check levels on a regular basis obviously and only use the genuine fluid for top ups.