Astra 1996 Estate

[philby88]

I have recently bought a 96 model Astra Merit Estate, 1.7L diesel. It seems to run fine the majority of the time, however there have been some instances where the engine does not start for about 5-10 minutes after turning it off, usually at the most inconvenient times eg. at a petrol station.
I am very inexperienced with diesel engines, but have been told that when starting the engine I need to wait until the coil light on the dash goes off. When having the problems above, the light has not been on at all, so I assume this is not part of the problem.
Any ideas????

[milktray]

Petrol engines work by having a spark being fired in the cylinders to ignite the petrol/air mixture. This is done by the spark plug.

Diesel engines don't have spark plugs, and instead rely on the piston compressing the fuel/air mixture so much thats its temperature increases to such a point that it spontaneously combusts. However, the engine needs a helping hand to start this process when you first turn it on, which is where the glow plugs come in.

When you first turn your ignition on, you should see an orange light with a coil showing on. As long as this is illuminated, the glow plugs are warming up. You need to wait for this light to go out before turning the engine over, otherwise it will struggle to start. On cold days, the glow plug light can stay on for 5 to 10 seconds, and on warmer days less, but it should come on for at least a couple of seconds. If you don't see anything at all, then you may need to replace them.

Glow plugs, just like spark plugs, should be replaced regularly as part of your service schedule.

Hope this helps,

Mark