I had not driven the car close to a month or so. When I first started her up, I noticed that the glow plug light did not come on and did not think much at the moment; As I proceded to ignite and thought (Low battery?) dismissed it. when I started it the light stayed on. (Well that's odd I thought at the moment) followed by some unusual knocking which made me think a glow plug had left or it is on its way out as the noise slowly vanished. The light stayed on for more than 8 seconds or so. I then decided to turned it back off.

Once I turned It back on. Everything back to normal including the glow plug light. (This was late in the afternoon after I had returned from work) then late last night I decided to give it another try after the car had cooled down. The glow plug light worked normal but the light knocking was present.

Erebus just turned 102k and the plugs were replaced at about 70k more or less.

Could it just be that one or more plugs that are leaving?

Your input as always is greatly appreciated.

Thanks.

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CM

When the light comes on after the engine has started means at least. One glow plug has either a short or has expired. The knock you hear would be a cylinder without the glow working.

Don't replace just one plug, replace them all. Make sure to ream the holes good.

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

Quick sanity check before going to the trouble of replacing the plugs. Make sure they are all connected good first.

I know the W210 based OM606 engine uses a plug-on connection, as opposed to the OM61x and OM603 engines that have the ring tongue/nut connection. Not sure what they did on the W124 based OM606, the ring/nut or the plug-on style.

Those plug on connections have been known to work loose and fall off.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

GP lamp not showing on Key on engine off and then showing up with key on engine run is actually the lamp telling you there is a problem with the system.

best pop the cap off the relay and undo the 6 wire connection, test resistance of each pin against a good ground to see which one is bad.

when you come to changing them - you need to get the engine blazing hot first. I did mine with engine running as I loosened the first threads, ATF + acetone as the creeping oil will help a little.

If they are really stuck you need to get a split nut tool to act as a reaction base in order to pull the plug from the head squarely out, But getting the engine really blazing hot is key here.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

Thanks all for the responses guys. They are all very much appreciated; These last couple of days I have been swamped at work and have not gotten a chance to get under the hood.

However I have noticed that sometimes when the car has sat for while - six hours or so. I warm her up and the blinker on the hazard switch was on without me turning the lights on or the switch for that matter.

Then the first two or three times that I use the turn signals they work. But the noise is not there and only after I try then in a few times the "tic toc" come back again.

The OVP relay was changed to a newer style less than I year ago. I am beginning to suspect a weak battery.

When the ignition key is turned on to accessories besides the GP light which are supposed to come on? I think that I am getting a few too many in the morning.

Thanks.

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CM

If you pull the plug off that goes to the glow plug unit you can check to see if the glow plugs are working with an ohm meter. Numbers on the plug correspond to cylinders. Connect ohm meter to ground and check resistance to each plug receptacle. Low resistance plug is working, no conductivity plug is burned out. Could be the control unit itself is going bad. or could be moisture got in something while it was sitting, try cleaning plug connections.

Hi guys, A quick follow up.

I actually had a bit of time yesterday before the rain started, and open up the GlowPlug box unit. and moved the plug a bit (did not have a chance to get the Multimeter out before the rain came) she started great this morning.

She acts up when I let her sit for a while, In regular use she works ok; I checked the battery the other day and after a day of sitting got a reading of 12.51 volts

Hopefully it wont rain this afternoon and I'll get a chance to test the glow plugs from the plug on the box.

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CM

You might want to clip a voltmeter from the negative terminal of the battery to the cars body. See if there is any reading when the key is turned on. Best done after the car sits. Or a jumper cable as long as you can find a good body point to get a solid ground contact with.

For the time it takes it eliminates a major poor semi intermittent ground situation. Also I might remove and clean the battery connections. You could chase your tail for a long time by not eliminating this type of issue as a possibility.

To me as you suggest there seems to be some indications of an intermittent low voltage situation too.

I think the Glow Plugs you have are of the type that the Hex Head often breaks off when you try to remove them. There is some methods in the DIY Repair Links to try to avoid that but there is still a chance of breakage.

That means is before you try to remove the Glow Plugs it is a good idea to have another ride to Work or other important places incase it happens so you can take your time and deal with the problem.

The possible issue of breaking the Heads off of Glow Plugs might give you caution on removing any good Glow Plugs.

Since I have other Cars to drive My own thought would be to remove all of them and if any break deal with that all at one time and make sure some Neverseez type compound gets on the threads so they will never get stuck again. Another option is to use the Beru Glow Plug Grease.

Once out use a Glow Plug Reamer or something to sub for that to clean out the Glow Plug Holes.

From what I have read an Auto Repair Shop is going to want to remove the Cylinder Head and send that to someone else to remove broken Glow Plugs. They do that because it is safest for them to avoid damaging the Head and at the same time it is more Money/Work for them removing and re-installing the Head.

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84 300D, 82 Volvo 244Gl Diesel

Thanks Guys,

Barry I will give the grounding issue another look. to be honest the Glow Plugs on this car are one of the only things that scare me a bit on this particular model. The stories of broken plugs that end up in heads having to come off is not something that one looks forward to.

However if one of them is out; I will most likely change them all out in one shot.

I have been thinking about Zulfiqar's input on post #5 of running the car blazing hot and then carefully removing those. Will the car run without the intake on and the other question that I had was that if the head on the OM606 is made of aluminium.

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CM

The car will run without the intake on, and yes, the head is Aluminum.

Rgds,
Chris W.
'95 E300D, 427K

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Objects in closer are mirror than they appear.