Different ambient temperature and plugging in the block heater have not made a difference.
They do on my 240D.
I will usually glow the car twice then turn it over between 2-3 minutes for 45 seconds at a time. While this is going on a grayish cloud of semi burnt diesel exits the tail pipe.
Sounds much worse than my 240D, which is a reluctant starter.
I have the old style loop glow plugs. The ones on the vehicle are at least 7 years and 100K miles old. Do these degrade over time?
In a sense. If they're drawing proper current (55A) at all they're not dead. The plugs themselves are very robust, and I believe will outlast the parallel plugs by a considerable degree. The connections to them, however, are vulnerable to corrosion. Each plug should measure approximately 1V between its ring and tip terminals while glowing. I've had trouble with bad connections on my 240D skewing this so that one or more plugs isn't getting full heat. Get out your voltmeter. Each of them should be eating 1V or thereabouts. If you have a clamp-on DC ammeter you can verify that they're drawing proper current, but most folks don't have one of these relatively pricey tools. If you have a series-connect ammeter that will handle this large current you can use it, but it's even rarer than a clamp-on. If _any_ plug is not getting proper voltage, because it's a series circuit it will indicate that other plugs could also be getting inadequate heat. A double whammy! You could pull a GP out to examine it for carbon build-up. -- Jim
