Vauxhall Cavalier N reg (95).1.7 TD. Isuzu engine. I seem to be going through glowplugs at least one set a year, yet have been told they should last 60 000 miles ? I replaced one plug several weeks ago as it had failed and now this morning the car was loathe to start. On checking the plugs the other 3 had failed. ( lucky if the set had done 10 000 miles) Does anyone else have this problem?