Om624 glow plug removal

[matthew k]

Hi, my cars needed new plugs for a while, so I'm soon to bite the bullet. I've ordered some made by Bosch, they looked closest to the Mercedes originals to me. Just a thought, does the diesel itself come into contact with the plug before it's injected? Must admit I have no idea how it works on a direct injection engine.

I just thought maybe some fuel cleaner added a few days beforehand might help shift any carbon that might cause them to be stuck? Cheers

 

[EmilysDad]

Fuel cleaner won't make a difference. You could give each of the plugs a squirt with a proper penetrating oil eg Plusgas a few times. Make sure the engine is fully hot before you start .. be careful & don't force the if they don't want to come out, they easily shear.

 

[KennyN]

I think you mean the OM642 engine ?

The plugs can be a bit of a PITA to replace , you maybe lucky and they come out without a fight but it is not unknown for them to shear in the process.

To give yourself a chance before attempting removal give all six a good dose of penetrating fluid for a few days before / after using the car that way it gets a chance to work into the threads.

Penetrating fluid / ceramic grease for re-assembly / torque wrench / 8mm deep socket.

K

 

[Wighty]

https://forums.mercedesclub.org.uk/index.php?threads/changed-my-e320cdi-glow-plugs.178177/
this was my GP experience last year , it may help

 

[Frontstep]

Keep a well fitting socket square on , don't snatch and tighten ever so slightly first.

As said a hot engine and some penetrating oil, not WD40 it doesn't do much which is why WD make a specific one.

I have heard good reports about using an impact gun.

I think something to remove carbon in the cylinder isn't a bad idea if it works.

There's plenty of google images showing where your fuel,plug and injector sit in the cylinder head.

 

[Uncle Benz]

Engine hot hot hot. I use a 1/4” drive socket set, gives a better feel for the yield point than a 3/8 set. Often a very slight nip in the tighten direction first, then loosen sees them come straight out. I’ve never broken one. If it isn’t shifting, plusgas and run for a week, then try again

 

[EmilysDad]

Engine hot hot hot. I use a 1/4” drive socket set, ...

I still managed to shear one of mine with a 1/4 drive T bar

 

[Uncle Benz]

I still managed to shear one of mine with a 1/4 drive T bar

Show off

 

[Frontstep]

They are a pathetic design fraught with disaster.

As our humble cars evolve feeble electronics held on with gnat wing spit will blight our lives next.

 

[matthew k]

Thanks guy's, V helpful.