Glow plug test

I pulled all the glow plugs on my '82 300CD, grounded them, and turned the key. No bad plugs here!

Category:

Autos & Vehicles

Tags:

• Mercedes
• 300cd
• turbo
• diesel
• glow
• plugs

[friedchicken1981]

ok so my question is: is it enough to see glow plugs become red to conclude that they are working properly? or is there a better way to test if a glow plug is efficient? what i mean is, can a glow plug become incandescent but still be not performing 100% or if it does become incandescent it means that they work hands up? thank you in advance!

[derherr65]

@friedchicken1981 Pretty much. It would not hurt to buy a couple spares and test all 7-8 you have. Put the hottest 5 in and keep 2 in the trunk. Colors from hot to warm would be yellow then orange then red.

[panoramama]

my 1983 merc has a probem with the glow plug

my coil light dosent turn on, its a pain on the butt in the morning because it wont start

what could it be?

[derherr65]

You have one or more dead glowplugs. The coil light is designed NOT to light if one goes bad... but sometimes it takes 2.

To test, disconnect the wiring harness and connect one side of a 12v bulb to power and the other to the glowplug. If it lights the plug and wire are good. If not, you have a bad plug or broken wire.

[interzoneinc84]

Was this recorded on a calculator?

[nutschTM]

@derherr65

Hello, do you think faulty glow plugs might cause my engine (diesel) to heat up slowly? I have to drive about 5km to get warm air in the cabin. It's taking longer than it used to take last year for example.

PS: My car doesnt have any antifreeze heating system

[derherr65]

@leigionslasher Yes, a dead glow plug will definitely affect cold starting and performance. It will start slower, run rougher, and have less power and economy until the cylinder gets warm enough to fire. On a 5 cylinder two dead plugs may keep the engine from stating in freezing weather. In my experience glow plug issues should fade within 15 second to 2 minutes from starting. If you are having 15 minutes of difficulty I would be suspicious of other issues.

[sin247365]

LeigionSlasher.. Yes exactly. The glow plug helps preheat the cylinder so diesel will ignite under compression. There is no spark plug. Furthermore. The glow plug ONLY affects cold starting. Only while starting. If your eng sounds like its running rough when u order start but clears within 10-15 min of running. It's a glow plug or an injector tip. But prob the glow plug.

[friedchicken1981]

@derherr65 thank you! :)

[2874697]

SPA.

[roaddiablo]

Where in Fl are you, I have been trying to find bio diesel near me, im in Fort myers an can't locate any.

[veggiepowered]

i just changed my glow plugs in my 83 mercedes 300td wagon i wish i would have made a you tube of the brand new ones heating up. the oil ones were totally dead. veggie power forever. VEGGIE OIL MAN IN FLORIDA