Checking And Changing Glow Plugs

[chrislloydie]

I have a 2002 tdi 115 auto (pd).

 

Been having some rough starts so want to check the glow plugs and replace if faulty.

 

Anyone point me to a 'how to' for either testing and replacing the plugs on my mk2 please?

[smudger]

you would need a multimeter volt tester set to ohms remove plug remove leads and connect multimeter to plugs it should give a reading around 3ohms, may as well clean them why they are out :)

[seatkid]

You dont need to remove the glowplugs to test them.

 

First remove the engine cover

 

Get access to your glowplugs -

On the Mk 1 (pre 2000) Tdi (photo below), the glowplugs are situated on the cylinder head under the injectors but

I think on your engine you have to remove the rocker cover to get to them ( but check as I may be wrong)

 

Pull the busbar off - this requires a hefty tug at each plug position.

 

Check the resistance of each plug using a multimeter between the plug top and the engine block (ground). THe resistance should typically be 0.3 - 0.7 ohm (not 3 ohms as suggested by Smudger). A faulty plug will be significantly higher, usually several hundred ohms - open circuit. Change the faulty plugs, I think a 10mm extended socket is required.

 

Dont forget to push the busbar firmly back on.

 

 

photo of Mk1 glowplugs with busbar unclipped

 

Edited March 18, 2013 by seatkid

[chrispb123456]

Mk 2's are actually easier to get at than the MK 1's in respect that there's no injector pipes in the way.

 

Remove the plastic engine cover and lift of the foam sound deadening material and you will see the bus bar connector facing you.

 

Then with bus bar removed.

Edited March 18, 2013 by chrispb123456

[chrislloydie]

Thanks fellas, very helpful. Will check them and replace as necessary. Are they easy to remove?

[smudger]

thought it was 3ohms been a while since i checked a glow plug my fault sorry, i knew it was 3 think my multi would show .3 hence why i said 3 lol, i always thought it was best to remove the plugs to test to avoid any in correct reading, like i said not done any diesal work for a while,

[acecard]

 Check the resistance of each plug using a multimeter between the plug top and the engine block (ground). THe resistance should typically be 0.3 - 0.7 ohm (not 3 ohms as suggested by Smudger). 

 

Theres quite a few on sale rated at 0.9 ohms - doesn't make much difference - just that a reading of around 1 ohm doesn't mean its on the way out.

 

All this is so much more helpful than the Mk2 Haynes which tells you to resistance check the plugs but gives no idea what to expect claiming that at the time of writing "this information is not available" :blush:

Edited March 19, 2013 by acecard

[BrianH]

thought it was 3ohms been a while since i checked a glow plug my fault sorry, i knew it was 3 think my multi would show .3 hence why i said 3 lol, i always thought it was best to remove the plugs to test to avoid any in correct reading, like i said not done any diesal work for a while,

 

As long as the busbar is removed then testing in situ should be fine, any odd readings should to show up tested in place or not as theres only a simple circuit involved with the ground running back through the outer metal of the plug.