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Why is my 2005 Holden Commodore overheating?

Asked by Eryl

My 2005 SV6 VZ Commodore has been overheating recently and the second time it had happened the power-train warning light came. I recently bought the car from a car-dealer second-hand and it was initially running smoothly. It was a hot day in Victoria (34-degrees) the last time it overheated, but although I was driving the car all day and with the air-conditioning on, it was only that night, at around 10pm, when it started to overheat badly. What could be the cause of this?

Answered by CarsGuide

25 Nov 2020 David Morley

There are many, many things that can make a car overheat. A faulty radiator, collapsed radiator hose, jammed thermostat, blown head gasket, low coolant level, incorrect ignition or camshaft timing, faulty fuel injectors, the list goes on and on. So you need to have the car scanned electronically to see if a fault code is offered up that could be the cause or part of the problem. First, though, I’d have a close look at the obvious stuff like a leaking radiator or blown radiator hose to make sure that it’s not a really simple fix. Even a faulty radiator cap – as simple as that sounds – can lead a car to overheat.

To be honest, a 34-dgree ambient day should never be enough to make a modern car overheat, especially not one like a Holden Commodore which was designed here to easily cope with our weather and temperature extremes.

It’s interesting to note that you bought the car from a dealer, so it would be worth going back and checking the paperwork to see if the car was sold with any warranty. It’s doubtful, however, as a 2005 model car falls outside the boundaries of Victoria’s statutory warranty legislation (generally a used car must be less than 10 years old and have travelled less than 160,000km before a statutory warranty applies from a licensed car dealer). A good mechanic who knows this type of car should be able to sort it, but have it checked soon; continuing to drive it with an overheating problem is a sure way to make small problems bigger ones.

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