Don't get me started on coolant or I’m likely to chew your ear off. When I talk to service managers about their fleet and they have a robust maintenance plan in place, when it comes to the coolant it seems to be the hardest area to get right consistently. Everybody has a different opinion as to the importance and the implementation. The smart money is on a scientific approach to this problem that has destroyed more engines than any other cause put together.

Instead of your engine going the full distance and only needing a liners, rings and bearings overhaul you are slugged for new radiator cores- water pumps -heat exchangers - cylinder heads - cab heaters etc. and 1000's of hours earlier than you should.

Some operators have taken the idiot out of the equation by buying pre-mix coolant and shoving it in any machine that comes on site and flipping it out every 2000hours. This has settled things down but I still see that machines going down with blown heads – liner failure – radiator core - water pump – heat exchanger failures that are accepted as normal, which they aren't.

The first problem is most daily check lists say check the water level in the radiator. It's not water it's bloody coolant!!! Only top with coolant

Some staff diligently check their radiator every morning when cold and find it low as expansion the previous day has dumped the excess and so top it off with the only thing handy – tap water – gradually diluting the coolant. This you will have to beat out of them!

Secondly your mechanics may be flushing out the old coolant with water then filling with new pre-mix. Because of the plumbing of the system up to 20% of the cooling system capacity is left behind when dumping the flushing water.

Lets say you have a 100ltr system and 20lts are trapped in the system

80lts of 50/50 premix is added

Which leaves you with a premix ratio of 60/40

So the system is depleted immediately.

There are a couple of ways around this problem.

Go after every drain bung in the system – block drain – heat exchanger bung – thermostat housing – heater core – radiators and get every drop or make your last flush with premix, thereby raising the premix ratio or sample and test the coolant after charging and adjust with coolant concentrate and maintain a sample and test process at every service by installing a drain cock in the engine block cavity so an accurate sample can be obtained as coolant drawn from the header tank has been known to give inaccurate results.

You should first establish what is in each unit using the manual and testing in conjunction. Some dealers don't even know what their units come supplied with.

Some coolant is not compatible and will neutralise or become acidic ether way causing eventual engine failure.

Some coolant needs a specific flushing agent to completely remove it.

Some flushing agents (12+ hour) can cause immediate engine failure.

Some machines the damage is done and you've got to roll your sleeves up and pull it apart.

It's going to be a long hot summer. Now is the time to get it right.

MECHTRONIK should be called in when -

You have an engine or transmission over heating

You have a series of cooling system failures

You need expert advice on procedures and requirements needed for immediate and ongoing cooling system maintenance planning

MECHTRONIK CEO David Armstrong can be contacted on 0409641195 www.mechtronik.com Heavy Equipment Inspections by Independent Mechtronik Specialists