Here's an interesting (for you, painful for me!) failure mode. I recently had to have the head pulled off my 1998 E300 turbodiesel to remove a failed glow plug which simply would not release its grip on said cylinder head. That sucker was really in there!

Turns out the root cause of the problem is a failed glow plug relay. It ran the little suckers too long, causing them to warp, and mechanically locking them in place. Ouch.

BTW, three separate machine shops refused to work on the OM606 head. Because the glow plugs are almost six inches long, they had no confidence they could remove the plug without destroying the head. I was _this_ close to buying an new head casting for $2300. Fortunately my mechanic is quite a diligent fellow and took it as a personal challenge to remove the recalcitrant glow plug. It required two weeks of patient work, but he did it.

All this headache caused by the failure of a $100 glow plug relay.

I don't have the car back yet, but that ought to happen tomorrow or Friday, whenever the new relay comes in. All that's left is to wrangle with the extended warranty company about what they'll pay. Glow plugs are not covered, but the relay is. But what about collateral damage caused by a failed part - namely the relay?

- Jim

- 98 210.025
- 87 124.193

That is an OUCH!

Sorry you had so much trouble with your glow plugs. My 1999 E300D also had the relay go out in it. When the relay went several of my glow plugs failed also. I was lucky and they all came out.

Is there a way to know that the relay is going bad or do I have to wait until the motor does not sound right on start up. That was my first clue to this problem.

Have a great day

Paul
1999 E300D
90000 miles

I read your notes again. Sure would seem correct to demand the warranty pay for all of this. At least for everything but new glow plugs. Even those did not fail, but were damaged by a 'covered loss' and its failure.
I would make a demand they pay everything and if they refuse ask them to explain thier basis of any denial.

Good Luck..

Ouch.

It could be worse...on the older Ford diesels, they used 6 volt glow plugs and apply 12 volts to them. If they stay on for longer than 8 seconds, they will swell up and will likely break...and if you lose the tip into the cylinder, the only way to get it out is to pull the heads. And not getting that tip out can lead to disasterous results. This is coupled to an old bimetallic controller that activates the glow plugs based on coolant temperature...and is prone to failing and leaving the glow plugs ON. This is why many of them have moved over to a push-button control.