For several weeks recently I keep getting the EGR indicator on, when interrogated with a micro can get an indication its a glow plug 3 problem, cancel it and its ok for several days then reappears  ---  should I move the glow plug to another cylinder to prove/disprove it is a plug prob or are there other reasons for this warning?

Edited 19 September, 20187 yr by Frenchtone

I'd start by measuring the resistance across all four glow plugs.

^^^That^^^

 

If you move the plug to another cylinder and the error moves, then the plug is suspect.  If the error stays then the wiring is suspect.  If the error goes away the whole thing is suspect!  That said, glow plugs are notoriously difficult to remove so I'd be looking at any and all options possible to avoid the unnecessary removal of plugs, healthy or suspect.

resistance , between the core and earth? if so tonight!

Yup, remove all four glow plug caps and measure the resistance between the glow plug core and a good earth on the engine.

 

They should all be similar and about 1 ohm if I remember correctly

Ok, so finally got time to have a look, and having spent some timefiddling with the removal of the caps with no success took a reading from the bezel at the base of the plugs, got 0.3ohms on all 4, how do the caps come off? any help greatfully accepted!