sooo....its -29..thats celsius...and my 93 aaz td has decided it wont start at all without being plugged in....right before the cold snap (around -10), it would start but with effort couple crankings...stumble and miss for 10-20 secs then smooth out and all is good........so im figuring its the glowplugs have finally died...(im not sure if it was ever really ruinning on all 4 or not...)
so i picked up 4 bosch ones...will put them in this weekend...
Can anyone point me to a little writeup on changing them out..or offer pointers that make it simple..
I realize its probably fairly easy....but ive never done it, so i figure id ask and save myself from any potential issues....
Thanks
Paul
number 1, you neeed ratcheting wrenches, and 8mm for the bus bar, 12 mm for the glowplugs as well, and a flexible magnet on a stick, for grabbing things that you drop (very very handy). ok so take all the injector lines off, it will be easier to change them and actually reach tem at this point, take the connecto off the tepmurature sensor at the head on the coolant flange, use a shallow 8mm socket to remove the bus bar nuts on the first 2 glow plugs. for the third and 4th, use the ratcheding wrench, you may need to pry the coldstart cable with a screwdriver to allow the wrench to fit on the nut for the bus bar, same with the 4th, there may be a bit of creative prying involved. lol then its pretty much the same with the glowplugs, 12mm socket firts 2 then wrench for the others. ok so installing them is a bit harder, use the magnet to position them and then hold them in place with a screwdriver until you can get the wrenh on them, (its a bit delicate of a procedure) and for the bus bar nuts, take some blaack silicone and fill the end of the wrench with it so the nut has a harder time to silp out, again you may need to hold the end with a screwdriver as you tighten it.
Something else. Take the nuts off 3 and 4. Loosen the nuts on 1 and 2, then remove one and 2 and use the bus bar as a tool to guide/lift them out, Same for the install..........
There's no shame in pluggin in in -29! Even with all 4 glow plugs, your gonna need a strong battery, winter fuel and a good IP. If I know it's going to be that cold, I always plug in for an hour or so before leaving just to be extra sure!
Ian
you can also use the magnet touching the screwdriver to hold the nut when you place it back on the glowplug. less messy than silicone. put it in place then hold and turn it with your fingertip to start it, then use the ratchet wrench.
One other suggestion... if you're gonna go to all the trouble of replacing 'em it's probably a good idea to also check that they are being fed... ie... confirm that you've got a nice solid 10-12V at the buss bar.
We see stories here often of folks replacing their glowplugs... still no joy... turns out the 50cent fuse was DOA. All that skin off the knuckles for nothing!
One other suggestion... if you're gonna go to all the trouble of replacing 'em it's probably a good idea to also check that they are being fed... ie... confirm that you've got a nice solid 10-12V at the buss bar.
We see stories here often of folks replacing their glowplugs... still no joy... turns out the 50cent fuse was DOA. All that skin off the knuckles for nothing! 
i was thinking of doing that.......so for an accurate test,..key in ignition set to start.....(so glowplug light is on.) then test with multimeter at bussbar?...fuse is on the firewall around the coolant overflow tank?then if thats good, im guessing the relay is also good
You got 'er... Ignition to "on" (I think that's what you meant) , the power goes battery -> relay -> fuse on the firewall -> bussbar -> glowplugs.
Depending on engine temp you have to be quick to turn on the ignition and then dash under the hood with your probes... I generally find a helper or pull the wires off the coolant temp sensors to extend the glowplug time to 30 seconds.
You got 'er... Ignition to "on" (I think that's what you meant) , the power goes battery -> relay -> fuse on the firewall -> bussbar -> glowplugs.
Depending on engine temp you have to be quick to turn on the ignition and then dash under the hood with your probes... I generally find a helper or pull the wires off the coolant temp sensors to extend the glowplug time to 30 seconds. 
thanks for all the help...i was *gasp* almost about to curse my diesel:)
Something else. Take the nuts off 3 and 4. Loosen the nuts on 1 and 2, then remove 1 and 2 plugs and use the bus bar as a tool to guide/lift them out, Same for the install..........
What's nice about this one is that the nuts are also started on the ones most difficult to get at behind the pump. Just watch that the nuts don't walk off while loosening/tightening the glow plug itself. A bit of pressure with a finger or something on the bar helps to keep this from happening.
Something else. Take the nuts off 3 and 4. Loosen the nuts on 1 and 2, then remove 1 and 2 plugs and use the bus bar as a tool to guide/lift them out, Same for the install..........
What's nice about this one is that the nuts are also started on the ones most difficult to get at behind the pump. Just watch that the nuts don't walk off while loosening/tightening the glow plug itself. A bit of pressure with a finger or something on the bar helps to keep this from happening.
all i can say is...that is not fun job.....but, its done...but what a b*tch....ugh....i followed the procedure abive but soomehow when putting the bus bar back in got the number 1 glow plug in the hole but number 2 was laying against the block...finally after much prodding swearing etc, go them in...but man that number 2 glowplug is not my friend.....and lol at the hayes manual...the r&r has pictures of removal with the head and just the head on a table...nthing getting in the way...how much help is that:)
oh, one thng though...in reference to the quote above i didnt watch closely enough ...and .lost a glow plug bussbar nut in the crevice between engine and ip pump....can anyone tell me what size thread pitch etc it is.....(i currently have an old pipe fitting nut on it...but it wont tighten right up..but still provides contact.....
Cheers
Paul
First time is the worst! It gets easier with practice.

If you have one of the old glow plugs, just use it to test out a replacement nut from your favourite parts or hardware store. One thing though, if it ain't tight, you will arc the threads up and you'll have to pull the plug again. Best get that nut ASAP.