My 82 Benz 240D doesn't start well in the cold morning, but will start in the warmer afternoon.....Why?

Question

My 82 Benz 240D doesn't start well in the cold morning, but will start in the warmer afternoon.....Why? I did change 3 glow plugs, but now the dash light doesnt work for the G plugs...still very hard to start when cold engine, but easy when warm.

Answer 1

You've still got a glow plug problem. If the light isn't working then the glow plugs probably aren't either. A diesel needs to be warmed to start. That's the job of the glow plugs. When the weather is warm or the engine has already been run then the plugs aren't that important. Get the glow plug system checked out.

Answer 2

Let's take this a little farther. All Diesels are harder to start in cold temperatures than hot weather.
Your Diesel glow plugs DO NOT WARM THE ENGINE! They warm the incoming air in the combustion chamber. The DO NOT warm the fuel air mixture.
A Diesel works by compressing, very quickly, the air alone in the combustion chamber, This very quickly heats up the air. Near top dead center, the injectors spray diesel fuel into the super heated air. The air is so hot, due to compression, that the fuel will burn and produce power. If your glow plugs are not working, the engine compression cannot preheat the air in the combustion chamber to a point, that with a VERY cold engine, the compression cycle can bring the air temperature under compression, to a point that can burn the fuel. The glow plugs heat the air in the combustion chamber to ease starting.
If the block and incoming air is warmer, it is easier to gain the correct temperature for combustion to occur.
On very cold days, continued cranking will eventually heat the combustion chambers to a point that they will support combustion, but you will see a lot of white unburned smoke while this is happening and just after starting, until the combustion chambers are hot.
Good Luck

Answer 3

In addition to the great answers regarding the block heaters and glow plugs, you might also want to look at the fuel return lines. If you have any fuel leaks at all, you're getting air in the system which will also cause the car to start rough. I have owned a 1983 240D for about 8 years, and I love it. It has right at 352,000 miles on it now. Those are great little cars. I wouldn't take ANY man's money for it! I did notice it recently beginning to give trouble starting, and a couple of the fuel return lines were wet-looking. I replaced them, and now, I just barely bump the starter and she fires off. I do agree, like I said, with the previous information about the glow plugs needing to be in working condition to pre-heat the combustion chamber, and the block heater warming the coolant, but you might want to make sure there aren't any fuel leaks, as well. Good luck!

Answer 4

Diesel fuel ignites when it reaches a certain temperature. A diesel engine accomplishes this mostly with the glow plugs and through compressing the air/fuel mixture, which increases its temperature. But if the engine block is too cold then the fuel can have a hard time reaching that temperature of combustion on every cycle hence the difficulty of starting.

One trick is to keep the engine block warm. A lot of diesel car owners have plug-in engine block warmers to help keep their engine block warm overnight. If you get one, just remember to unplug it before you drive off. :)

Answer 5

that's certainly a gas situation, no longer an glow plug situation. It feels like the two trapped air or a pump situation. probable a clog. in case you put in the appropriate plugs, Autolites are purely wonderful. examine the gas gadget taken to injector router.

Answer 6

82 Mercedes 240d

Answer 7

First you have to define "cold" morning. +32, -10, -20, -30?
Then I would still go with Mustange... above