Technical Changing a glow plug - easier than led to believe

[Herts Hillhopper]

My 2018 4x4 MJ has been showing a 'check glowplugs' warning for a little while. Although it was starting and running fine, thought I'd better do as it said. I checked the resistance of each plug and found that three of them were less than a few ohms (apparently it should be 0.3Ohm but my meter not that accurate), but one was open circuit - clearly the failed one.

There have been plenty of horror stories here (inc one from me!) about needing to remove turbos, needing loads of penetrating oil, doing when hot and so on, but that was not my experience today. With the right tools the whole job (to replace just the failed one for now) took less than 30 minutes (inc stopping to take the photos) and was all quite painless.

Here's the steps: (see photos too...)

• To start, I removed the bolt securing the end of the engine air intake. Then, by pulling and twisting at the same time, this just detaches from the air filter housing.
• I removed the heat shield from over the turbo (engine 'luke warm') - there are two nuts and two bolts, all 10mm heads. Take care not to drop the bolt on the front, as it then falls onto the sump guard (on the 4x4) -- I did that when testing them the other day, and it took longer to remove the sump tray to recover the bolt that any other part of this!
• Using a 'pick' tool, I was able to unclip the glow plug lead and move it to one side.
• The glow plugs need an unusual, 9mm socket. I used a 6-sided (high torque) deep socket (much less likely to round anything off than a 12-cornered one), coupled with a universal joint and the long extension of my 3/8" drive socket set. The plug was 'tight-ish' but not hard to initially loosen, and then unscrewed easily. Note its a long and fine thread so needs lot of turns to fully remove.
• To extract the now loose plug from down where it lurks I used a magnetic pick-up tool!
• Having checked that the replacement was the same size and length (the original part was labelled 'Hidria', but my replacement was NGK), I popped the new one in, and using the same tools wound it up to finger tight.
• The torque wrench setting fro the plug is just 12Nm - that really is just finger tight and the tiniest tweak further...
• I lined the plug lead back up on the plug and used the blade of a long screwdriver to push it fully home until it clicked.
• Reassembly is (the classic) 'reverse of removal'.
• Engine started - all warnings gone.

The replacement glow plug was NGK part number Y9001AS, and they were about £14 each from GSF car parts (I bought two...)

To see photos - click first thumbnail, then can use the 'previous' and 'next' arrows on the images to step through.

 

[vexorg]

I've also read all these horror stories of glow plugs, but I've changes them on a number of different cars and in general they have been no worse than stark plugs at coming out.

 

[Herts Hillhopper]

the 9mm deep hex socket, does it matter if 1/4", 3/8" or 1/2" drive?

I would suggest a 1/2 inch would be too big to fit (too 'chunky'), and 1/4 might not be strong enough if the plug is tight. It just happens that my 'Metrinch' set is 3/8 drive, and that all fitted nicely. (Look at the photo with the socket in situ - there's not a lot of room around it and the universal joint, and I suspect a socket with a 1/2 inch body and joint would be catching on other bits, such as that oil pipe to the turbo. There's a 1/2 to 3/8 reducer on the torque wrench...)

 

[AndyRKett]

My understanding with these is they should be an quick and easy job but because the plugs are very narrow and thin they have this tendency to snap off when you try to remove them, turning a quick job into a long ordeal.

 

[WitleyPanda]

I would suggest a 1/2 inch would be too big to fit (too 'chunky'), and 1/4 might not be strong enough if the plug is tight. It just happens that my 'Metrinch' set is 3/8 drive, and that all fitted nicely. (Look at the photo with the socket in situ - there's not a lot of room around it and the universal joint, and I suspect a socket with a 1/2 inch body and joint would be catching on other bits, such as that oil pipe to the turbo. There's a 1/2 to 3/8 reducer on the torque wrench...)
View attachment 421083

I had totally forgotten that i own a full Metrinc set, but found a 3/8" halford deep set instead.

 

[WitleyPanda]

My understanding with these is they should be an quick and easy job but because the plugs are very narrow and thin they have this tendency to snap off when you try to remove them, turning a quick job into a long ordeal.

And the plan "B" is? Or is it a head off?

 

[AndyRKett]

And the plan "B" is? Or is it a head off?

Drill it out really REALLY carefully to hopefully get an extractor in there and apply a lot of heat... or yeah Head off.