When a timing belt breaks the damage it causes could prove expensive and, after the breakage, it is essential to determine why the belt broke before simply fitting another one.
A Nissan owner asked me what could have gone wrong. He said the belt had broken before with damage to the head, pistons and valves and a friend who is “good with engines” had renewed what was necessary and everything had been okay for about 15 000km.
He asked why should it break again. Well, to even guess an answer I needed to examine the belt to find out if it simply snapped, or was it torn apart.
Was it a genuine original equipment fitment, or a cheap alternative?
Was it actually fitted correctly?
There is a spring-loaded adjuster pulley to ensure the correct tension, but this can be over-ridden and set up manually. If the belt was set up incorrectly this could have been the reason for breakage.
A few teeth missing from the belt could suggest it had jumped, but far more likely is a problem with the adjuster or perhaps even the water pump.
The snag when checking the water pump is that after it has locked up and the belt breaks the bearings are no longer under tension and, on checking, may seem to be free running.
Any roughness in the bearings or “catching up” of the balls in their races will no longer be felt. For this reason I believe in fitting a new pump after belt failure has occurred.
By all means get the pump checked professionally and if the tester says it is okay, keep your fingers crossed!
The adjuster pulley should also be thoroughly checked and, if in doubt, renewed.
If either of these items has been on the vehicle for a very high mileage or several years without attention, play safe and renew.
What proved to be a minor problem almost brought an end to marital bliss.
People often use differing starting techniques and most of the time no harm is done. But when a local man’s car was off the road, he borrowed his wife’s car and had starting difficulties.
He was used to depressing the accelerator before attempting to start the engine on his own car, but on her car this simply brought about a non-start situation.
The only way to get the engine started was to take out the fuel pump fuse and crank the engine via the starter.
It did not occur to him that the wife never had such starting problems.
Possibly to save face, he asked me to have a look at the car and all I did was clean the air-mass meter with a brake-cleaning spray, rather than a carburettor spray which tends to be aggressive.
I used the spray only – no brushing or wiping with cloth.
I cleaned the idle-speed control valve too, but on this you may use a brush.
After that the car started easily irrespective of who was in the driver’s seat.
I nevertheless recommended that he should get the injectors cleaned and tested. No divorce so far; we live in hope. - Star Motoring