Glow plug replacement

[langers2k]

13 minutes ago, ords said:

If the glow plug doesn't unscrew at the max recommended torque, what are you supposed to do?

 

Apply heat, penetrating oil etc and hope it comes out...

 

If not, add more torque until it either comes out or snaps. Once it snaps, drill out and heli-coil it 

[ords]

5 hours ago, langers2k said:

 

Apply heat, penetrating oil etc and hope it comes out...

 

If not, add more torque until it either comes out or snaps. Once it snaps, drill out and heli-coil it 

Exactly. Seems a ridiculous guidance to me. 

[dieselV6]

On a previous car (Mk1 Superb), I had 1 problematic glow plug. I tried undoing it to the torque limit, wouldn't budge. So I drove for another week with some motor oil around the glow plug. Afterwards I tried again to the limit, the glow plug came out without much protest.

Had I not  known the limit, I'd have snapped the plug on the first attempt. I'd say knowing the torque limit was useful to me, 

YMMV, but please note not everyone works on workshop timescales, a lot of us are fixing our own cars... on our own time/dime

 

 

[Daheee]

Ty for the replies. I will put more oil round it and give it a few more days. I am using Bosch plugs so might go 2nm over the 17nm tightening spec next time I try. Will let you know either way.

[Breezy_Pete]

I suspect you will have to get much more brave.

[dieselV6]

1 hour ago, Daheee said:

Ty for the replies. I will put more oil round it and give it a few more days. I am using Bosch plugs so might go 2nm over the 17nm tightening spec next time I try. Will let you know either way.

 

1 hour ago, Breezy_Pete said:

I suspect you will have to get much more brave.

 

Even subtracting further 5Nm from the lower value to be safe for caution, you should be OK with 30Nm torque for undoing, these are M10 plugs. Also, even if it does not appear to move, if the glow plug is surrounded with oil, applying some sensible torque might allow oil to penetrate deeper in the thread

[SuperbTWM]

I've had good luck using a small impact wrench/driver, keep it on a low enough setting so it just sits there and gives it a good rattling to free things up. The vibrations might help

[J.R.]

It surely does, I have had amazing results with my Bosch 18v 1/2" drive one (not a small wrench) on completeky rusted trailer fasteners that I never had before when using an air dugga-dugga.