Diesel glow plug relay fix

[George Holmer]

This is applicable only to diesel engines but might still be of interest to owners of such vehicles. My very well maintained turbo diesel would start up badly in the morning and smoke, the colder outside the more smoke, lots and lots of smoke. I knew all the glowplugs were brand new so I suspected the glow plug relay. I opened it up and lo and behold, there is a copper plate partially split in two with two contacts at the split end. The smaller bit was seriously affected by heat and had severe discolouration. The contact was badly pitted and the copper had bent downward sligthly causing this contact to meet but not the other one, thus rendering the relay useless. In my case, with severe pitting the relay will soon need to be replaced but just cleaning the surfaces with a sandpaper and bending the two split parts of the copper plate and making them level has made my car start up much, much better and there is much less smoke. Since I did this, a number of other diesel owners have confirmed that their relays have suffered similar fates. If your diesel is a hard to start from cold and smokes badly, the glow plugs are often the culprit but do not forget the relay, it's easy to check and fix.

George

Anglo-Swede resident near Leuven in Belgium

'87 745 GLE Turbo Diesel Intercooler (D24TIC/M46, 200k)
'88 745 Turbo Intercooler (B230FT/M46, 270k)
'88 745 GL (B200E/M47, 200k)
'89 440 GL (B18K, 90k)