Replace Glow Plugs of CRDI Engine

In the above image you can see a plug fixed to a power wire (left) and a metallic power strip (right). I have mine wrapped in duct tape to prevent it from connecting with the car's body.

Removing the Glow Plugs From the Engine

Remove the screws with a wrench and, to make sure they don't get lost, place a plastic bag between them. Remove the power supply of all the plugs, in my case — three of them. Then, remove the power strip and take it out.

To better understand the process here's a picture of the plug's power strip on the disassembled engine:

Now we have to unscrew the plug itself with a 10 mm wrench. If it gets stuck, you can spray it with some lubricating oil. You can also put a rag between the plug and the engine, pour some lubricant on it and leave like that for a day.

It's best to do it with a warmed up engine, since diffusion and other physical processes depend on the temperature.

Why leave it for such a long time? Just in case, since removing a broken plug would be much more complicated and would take much longer. I don't think that the ones I have can be broken though, since they're made of a single metal part with the positive terminal on top.

Checking the Condition of Glow Plugs

After removing the plugs, not throw them in the trash just yet. You can check their condition and if they're still good you can keep them for emergencies.

During the check you should be very careful since defective glow plugs can get short-circuited. It happened to me once: in the first picture the hole in the battery formed while I was trying to check a plug with the short-circuit inside.

To check if it works you should power it with the battery with thick wires.

If it's in good condition it will heat up for a couple of seconds until it becomes a red-yellow shade. I connected the positive terminal through a nut so the electric arc wouldn't damage the screw.

I don't recommend checking the plugs if you can't charge the battery or start the engine (witout glow plugs you can not start the engine. You know, cylinders have openings instead of glow plugs).

Installing new Glow Plugs

Now we just have to place the new plugs in the engine (part number 36710-27000, I ordered for the original (HYUNDAI/KIA), but I got some NGK in a MOBIS box), install the power strip and screw it on. It sounds simple, but you know it isn't.

You have to improvise with different positions for the ratchet and the wrench until you find one where you can turn the plug and then screw it on.

Placing the power strip takes a little patience, since you to install it over all the plugs at the same time. Fix the screws the same way you removed them, adjusting them with the wrench after placing a bag or something like that.

Don't screw them on too hard — the plug's contacts are thin and easy to damage. Place the device that separatesthe oil from the gases back, then the wires and finally plug everything back in.

Deactivating the Glow Plugs After the Winter

My car can start without help from the glow plugs at temperatures down to -5 °C. At the same time the plugs are powered by the battery even during summer with a warm engine. That's why you should deactivate them until next winter.

Unplug the plug's connections:

The Inside of a Glow Plug

For curiosity's sake I disassembled one of them. The thermal element is a wire shaped like a coil in a ceramic casing:

The positive terminal and the insulators:

Cars that use the same glow plugs (36710-2700):

1. HYUNDAI ACCENT [AW]
2. HYUNDAI ACCENT [BA]
3. HYUNDAI ACCENT [BA]
4. HYUNDAI ACCENT [BG]
5. HYUNDAI ACCENT [LC]
6. HYUNDAI ELANTRA [CA]
7. HYUNDAI ELANTRA [CG]
8. HYUNDAI GETZ [BJ]
9. HYUNDAI GRANDEUR [EL]
10. HYUNDAI GRANDEUR [TG]
11. HYUNDAI I30 [JD]
12. HYUNDAI MATRIX [BE]
13. HYUNDAI SANTA FE [BB]
14. HYUNDAI SANTA FE [BM]
15. HYUNDAI SANTA FE [CM]
16. HYUNDAI SONATA [EK]
17. HYUNDAI SONATA [ER]
18. HYUNDAI SONATA [NF]
19. HYUNDAI TRAJET [EC]
20. HYUNDAI TRAJET [FO]
21. HYUNDAI TUCSON [BH]
22. HYUNDAI TUCSON [JM]
23. KIA CARENS [BK]
24. KIA CARENS [UN]
25. KIA CEED [ED]
26. KIA CERATO [CD]
27. KIA MAGENTIS [DD]
28. KIA OPTIMA/MAGENTIS [MG]
29. KIA SPORTAGE [FQ]

Cars, which used the same engine (1.5 CRDI D3EA, 3 cylinder):

1. HYUNDAI Accent
2. HYUNDAI Getz
3. HYUNDAI Matrix

Cars, which used the same engine (2.0 CRDI D4EA, 4 cylinders)

1. HYUNDAI SANTA FE
2. HYUNDAI TRAJET
3. HYUNDAI TUCSON
4. KIA CERATO
5. KIA SPORTAGE