I know that worn (or even faulty) glowplugs are causing me problems when it comes to starting on cold mornings as it takes 2 or 3 goes at the pre heat thing to get things going but would such a problem also cause other problems.
As I understand it, glow plugs are to a diesel as spark plugs are to a petrol so I would have thought that worn plugs may cause reduced power and/ or reduced fuel economy as well.
Am I right in my thinking?
Thanks
Nope. Heater plugs are an aid to starting diesels. Nothing more.
Once it's running (slightly open ended statement, for some cars running is after the first ~30seconds) the combustion chambers hot enough it doesn't need them.
Sorted. That's just what I needed to know. Thanks
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Exactly. Once running, the heat of compression keeps your engine running. The glow plugs switch off and take no further part in proceedings. Not all cars have glow plugs in all cylinders - I think we discussed a Rover engine with 3 plugs in a 4 cyl. engine a while back.
I know that mine has 5 (one on each cylinder) and as I have just reached the
100k miles mark, the need to change them is not a surprise or premature but I just wanted to check first.Thanks
And if it's a direct injection engine, it'll have no glow plugs in the cylinders, it may have a thermostarter.. which is a glow plug and injector combined, this is fitted to large-ish van engines mainly, it's in the inlet manifold after the turbo, and it sends heated or flaming diesel into the combustion chambers when starting a very cold engine.. mine only comes into play when the coolant is below 2 degrees C,
So appart from extermely cold mornings, the engine starts with no heat assistance at all, and fires the second the starter touches the reing gear most of the time, at the most it takes 2 revolutions to get her going, but that's how a direct injection engine should work.
On older DI engines the above is correct- no glow plugs, but possibly a thermostat in the manifold which works just like a self igniting flame thrower (on a smaller scale)
However on most of the new DI's we're seeing glow plugs back again, of a slightly different breed yes, but they are there and sticking into the combustion chamber. However they don't work unless it very cold- those on the PSA HDI engine dont power up until its -6 degrees ambient or lower.
Tim..
hi to all, I have a vw golf mk4 tdi. what type of engine is it.direct injection or indirect? and do I have glow plugs or the manifold heater thingy? cheers,mark.w
Direct injection, and I don't know about the other bits - although I recall that Golf TDIs have a glowplug timer that kicks in when you open the drivers' door.
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