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Glow plug removal
mookaloid - 3/4/14 at 10:54 AM

Might have to replace some glow plugs in my sister's Avensis D4D

Any tips for making sure I don't break them and leave a stub in the head?

Cheers

Mark

adithorp - 3/4/14 at 12:21 PM

Not a lot youcan do to reduce the risk.

Use the largest size socket set you can and the shortest extention; That reduces the spring in the tools. Apply a steady smooth torque rather than a jerk, a long ratchet or strong arm helps but carefull how much force you apply. Try to keep all forces rotational and not sideways.

Other than that... fingers crossed and arse clenched.

Slimy38 - 3/4/14 at 12:39 PM

I did hear mention that some people have had more success with a hot engine, others have had more success with a cold engine.

britishtrident - 3/4/14 at 01:01 PM

I knew a Landrover mechanic that always poured a can of Cola over glow plug or injector recesses and left to work overnight magic. The phosphoric acid in the Coke is pretty effective at removing aluminium or ferrous corrosion, it is really dilute Naval Jelly or alloy wheel cleaner.

Plus Gas would be my choice or the 3 in 1 brand Penetrating spray.

britishtrident - 3/4/14 at 01:08 PM

quote:
Originally posted by Slimy38
I did hear mention that some people have had more success with a hot engine, others have had more success with a cold engine.


That used to be a hot topic with regard to the cylinder head bolts on Hillman Imp engines the head bolts on which were very easy to shear.

With a hot engine steel into aluminium alloy differential expansion increases the tension in the bolt but increases the diametrical clearance.

[Edited on 3/4/14 by britishtrident]

adithorp - 3/4/14 at 02:40 PM

I've not found corrotion to be the isseu with modern glow plugs. It's just the tightness of the taper seat and small diameter/weakness of the plug. Once they move they come out easy enough and any tightness then I apply easing oil and go forward/back to work it down the threads. It's the initial crack off the taper thats scarry.

acb2713 - 3/4/14 at 07:00 PM

Only this lunchtime I removed all four glow plugs from my Isuzu KBD25 pickup, 1977 vintage with the C190 engine. They could not have come out any easier. The engine was cold. The only problem I had was access to number one cylinder, due to the fuel pump being in the way. A flat 12mm spanner on number one cylinder, and 12mm deep socket on the others was all I needed. Just like you, I was scared, from tales of broken glow plugs... Hopefully, yours will be just as easy.

I hear some anti-seize lubricant is recommended on the thread when fitting the replacements, which I hope to buy tomorrow.

froggy - 3/4/14 at 07:19 PM

any glow plug that requires a 12mm socket to undo it will normally come out due to the amount of metal around the top compared to the lower section . this all goes out of the window with later longer plugs with an 8mm socket and usually m8x1 thread .

not common yet but i have a pnuematic hammer that grips the top of the plug and hammers upward so you can work the plug as you undo it to break the corrosion in the bottom of the plug which causes the head to snap off . havent broken one since including sprinters and tdv6 . hot engine helps with the thinner plugs but they dont take much to snap even using a stubby 1/4 drive ratchet .

b3ngy - 3/4/14 at 08:28 PM

I changed the glow plugs on my old e46 bmw. Did them with a warm engine and plenty of penetrating oil before attempting to remove them.

One method of removing a snapped glow plug I read about was to to drill and tap a left hand thread in to the glow plug, then using a left hand threaded bolt of the same thread screw it in to the end of the glow plug. Tightening the bolt unscrews the snapped glow plug.