Test if glow plugs are working
Thread Starter
Member
Joined: Oct 2004
Posts: 188
Likes: 3
From: Denver Metro
2017 GLC 300 Coupe'
Test if glow plugs are working
05 CDI
Can the dealer run a diagnostic to see if the glow plugs actually come on in cold temps? Had all the plugs replaced. Left car out over night in very cold weather. Glow plug lamp did not stay on any longer than when the car is warm or in the garage.
Any ideas on how to tell?
Can the dealer run a diagnostic to see if the glow plugs actually come on in cold temps? Had all the plugs replaced. Left car out over night in very cold weather. Glow plug lamp did not stay on any longer than when the car is warm or in the garage.
Any ideas on how to tell?
Super Member
Joined: Aug 2007
Posts: 603
Likes: 0
From: Spicewood, TX
2008 GL 320, 2007 Silverado LTZ C3500 Duramax Turbo Diesel
I haven't notced my glow plugs taking longer in the cold on my recent diesels, but it rarely gets below 25 degrees here. My old diesels (80's) definitely stayed on longer in cold weather. If it starts normally, I would say the glow plugs are OK because there is usually a significant difference when they are not working. Sometimes they will barely start after a lot of cranking, if at all.
Super Member
Joined: Dec 2007
Posts: 898
Likes: 9
From: Woodstock, IL
His 2019 RAM Cummins Turbo Diesel Laramie; Her's 2007 ML320 CDI P3; Mine BMW R1200R
Here in NW Illinois I go through extreme cold spells and have yet to note any significant delay in the lamp on time. Maybe .5 sec if that. I just bump the key and let the system start itself regardless of outside temps. I had an '04 Dodge Cummins Diesel truck before the '07 ML, and even then can't remember the glow light staying on much longer in Winter. I think glow plug tech has improved a lot over the years, so no worries.
Senior Member
Joined: Sep 2003
Posts: 351
Likes: 4
From: Christchurch, New Zealand
17 E220D, 11 E350 CDI(sold), 06 CLS320 CDI (sold), 05 Cadillac DeVille (gone), 04 E320 CDI (sold)
Our ML270CDI started blinking the glow plug light after a few seconds, it went out as the car warmed up. Apparently this is an indicator for a faulty glowplug, and went away once the plug was replaced.
