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Dear advisor,

I've just bought a 2001 car that has a timing chain-driven DOHC engine. It's done 136,000 kms. Should its water pump simply be inspected regularly? Or is it time to have it replaced to avoid problems? Would doing so be costly? I don't know if the timing chain needs to come off (just like a timing belt?).

Also, is it true that a well-maintained car's timing chain can last as long as the car?

Thanks for your advice.

Leo

Hi Leo, good question. Generally speaking, it is good practise on cars equipped with cambelts to change the belt and the water pump together at around 100,000km. The main component that needs replacing is the cambelt, but as the pump is driven off the cambelt, it is advisable to change it for two reasons. Firstly, as the belt will be there for another 100,000km, it is asking a lot to expect the water pump to last another 100,000km (ie; for 200,000km).
Secondly, (and most importantly) there is a danger that if the pump seizes, it will snap the cambelt and cause major engine damage.
On a car with a timing chain, the water pump is usually driven off an external drive belt, like the alternator, power steering pump and air conditioning compressor. The water pump is more easily accessible, therefore a less complicated job to replace in the event of a leak or failure. Also, in the event the pump seizes, it's only a drive belt at risk, not a timing belt that can destroy the engine.
Therefore, there is usually no requirement to change the water pump unless it starts to cause problems.
Regarding the chain, they are designed to last the life of the engine and in most cases, they give very little trouble.

Dear ABayliss,

Thanks very much for your valuable advice. I've learnt much from you about how things work. Your help has also enabled me to understand what needs/does not need to be done, and why.

Best regards,
Leo