3.0d e53 glow plug change
 

Afternoon all. In the new week or two I’ll be doing the vacuum hoses on the 3.0d e53. While the inlet manifold is off do you think I should replace the glow plugs and relay as there not working. If so what’s best way of getting them out with them breaking.

Pre treat with release agent like kroll or liquid wrench and use impact tool vs breaker bar.

The main thing is that you warm up engine properly before removing the glow plugs.

By the way are you talking about M57 or M57N engine (pre-facelift vs. facelift)?

M57 engine pre facelift

Then it's unlikely the glow relay would need changing. The relay on these older systems fail very rarely. This DDE 4 has only one available fault code for entire glow system. That's why the code is for glow relay or glow plugs even if only one glow plug has failed.

With a warm engine and some release agent, they shouldn't be so tight that you need either an impact tool or a breaker bar!

Seriously - these things are fragile. Install torque is like 18Nm, release is like 25Nm max - since they shear off at about 26Nm!! :yikes:

They DO get jammed due to carbon build up and I guess sometimes force is required to get them out if that is the case. But you would want to hope it's not! :thumbup:

I'll take the advice of somebody that runs an oil burner. I'm using general advice that impact is much less likely to break things or strip threads. Doesn't have to be 1100 ft·lb monster can be the little Milwaukee M12 screw impact.

You are correct Andrew - the impact is much less likely to break things - and it's my usual tool of choice with threaded fittings that can be tough to break free too. It's just that in the case of these glow plugs, the outer hex is on a thin wall and the head (inc. the hex) can easily twist/shear clean off the body of the plug. These things aren't like spark plugs. :(

My personal approach is to tackle these slowly, on a warm engine (to soften any carbon deposits), with lots of penetrating oil and a 1/2"-drive torque wrench set to (in the case of the M57) around 25Nm. If they don't start moving before I hit 25Nm, I would stop.

Fortunately, they have always moved before then (for me). Phew!!! :thumbup:

Actually according to manufacturer (Beru) the shear torque on these (M10 thread) is 35 Nm.

Their recommended tightening torque is 15 Nm, BMW recommends 18 Nm.

https://www.beruparts.eu/content/dam...glow-plugs.pdf

Thanks for the extra info. Clavurion. :thumbup:

Interesting to note that Beru suggest applying power to the glow plug to heat it up, as an alternative to warming the engine.

Which raises another note (for the sake of the thread...) - the M57 uses 12v glow plugs but the LCI cars with the M57TU uses 5v glow plugs. Beru note only applying power to the older 12v plugs. They may state this simply because a high current 5v power source is not a common option for most mechanics but it generally means that those of us with the M57TU will be warming the engine before disassembly.

Applying voltage will work if the glow plug been removed id not totally dead.

Newer alternate supply voltage plugs are basically 5 V glows (for longer after glowing) but can withstand short period of 12 V supply like on the pre-heating before engine start.

I use my torque adapter (think digital torque wrench) to monitor breakable things when removing sounds like this is one of those cases.

Heating the engine block will make the hole the plug is in bigger. Heating the glow plug will make it bigger which sounds counter intuitive until you realize that it's thinner than long Soo you will be reducing the tension on the threads. Both combined might work well. Also, like tapping threads, back and forth can get the carbon out and if you get any motion and it binds, more liquid wrench, it will capillary through the entire threads