Starting without letting glowplugs preheat - PeachParts Mercedes-Benz Forum

andy · #1 07-21-2002, 05:58 PM

Is it going to hurt anything if I start my car by just turning the ignition without letting the glowplugs preheat? The car starts right up. The only time I need to let it preheat is early in the morning or late in the evening when the weather cools down. It's been about 106-113 degrees here in palm springs. andy

#2 07-21-2002, 07:23 PM

I am told that on diesel trucks with glowplugs this is a bad thing to do because the glowplugs should not have heat applied when the cold diesel hits them. However, I think there may be a part of the circuit in a Mercedes that turns off the heat to the glowplugs if the ignition switch is taken to the starting position. Anyone know for sure on this?

speedy300Dturbo · #3 07-21-2002, 07:26 PM

The owner's manual for my 300D states that when the engine is hot, it can be started immediately without waiting for the glow plugs.

84300DT · #4 07-21-2002, 09:12 PM

the owner's manual on my '84 says the same thing -no need to glow on a warm engine.

psfred · #5 07-22-2002, 08:52 PM

So long as it starts right up (less than one engine revolution). If you actually have to let it crank for more than a couple (3) seconds, you are working the starter harder than you need to. The glowplugs make starting much, much easier on the starter and battery. I assume you have the AC on all the time, so you are putting a pretty good load on the alternator, too.

It only takes a few seconds at that temp to get the plugs hot, so I always use them.

Believe me, in the winter you will want to use them anyway!

Peter

turnne1 · #6 07-23-2002, 02:15 PM

My car will start right up in anything over 70 degrees...even with a cold engine...so in the summer..I hardly use them

Warren
1992 300SD 144K
Columbus Ohio

#7 07-25-2002, 11:14 AM

i work with dieselengines every day

warm engine there is no need to preheat.

when u preheat and start to crank the glowplugs will continue to glow a little while(even with engine running), just because the preheat light has turned off it hasnt stopped preheat, the light tells like "it ok to crank".

hopes my answer made something cleared

190D22 · #8 07-25-2002, 11:36 AM

Well a few days ago in the morning I tired to start it without preheating, don't know why, and I didn't crank more than 2 seconds. I preheated and it started but was smoking pretty badly (I could see smoke all around the car) and once I started moving the smoking stopped. I always let the light go out, no matter what. Unless it's only been no more than 20 minutes since I drove it then I will just start it right up.