22 March 2008

Nissan Micra K11 water pump drive belt

I scoured the internet for guidance this morning, and having found nothing that answered my questions thought it worth sharing my new knowledge, exiguous though it is, with the world at large.

Tor picked me up from the station on Thursday evening and the engine was over-revving and running very hot. We topped it up with water at a filling station on the way home, and it took a fair bit of water, but the problems persisted. Yesterday I tied squeezing various hoses to try to get any airlock out of the system, noting particularly that the heater hoses were cold but warmed up when I squeezed them a few times. It didn't provide a permanent fix, though, and I concluded that it was probably a minute leak in the radiator or one of the hoses.

Google led me to the suggestion that airlocks are better cleared if the car is jacked up so the radiator is a little higher than usual, but all I managed to do was get the temperature up to boiling point - which led to spectactular results when I removed the radiator cap. I was reconciled to adding K-seal to the system and hoping that it would block the invisible hole, when I noticed first a small shaft protruding from the end of the engine by the alternator drive belt, and then a couple of pulleys with no belt on them. My imagination quickly led me to the conclusion that one of these would be on the water pump, and there was a corresponding pulley on the end of the crankshaft, unfortunately behind the alternator drive belt.

Interpart provided a Haynes Manual to add to my extensive collection, along with a replacement belt. Between snow flurries, and with frequent stops to scrub my hands clean (forgot to buy latex gloves when I bought the manual) and warm them up I got the new belt on. Mr Haynes suggested taking off the front offside road wheel and then removing some of the plastic inner body parts to get access to the pulleys, but with a bit of fiddling and a few minutes on my back under the car I managed to loosen off the alternator belt without dismantling half the car - there is not space to get it right off, not easily anyway, but with it loose I could infiltrate the replacement water pump belt into place behind it. The bottom alternator fixing bolt was hard to get to, and very, very tight - eventually shifted by putting the trolley jack handle over the ratchet drive for the socket (14mm incidentally) which I managed to get onto it by feel alone, and using it as an extension bar. The pulley wheel by the water pump also proved challenging, with just enough clearance between it and the bodywork to get a 17 mm ring spanner over it - which then required the application of the jack handle to the other end of the tool to get enough torque to shift it.

It was good to see the belts and pulleys turning as they should once I had tightened everything up again, and reassuring to find that I can still fix things sometimes - so long as they are't too complicated ...

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