XSeries-forum

My X5 chucks out a little cloud of white smoke and a stench of unburnt diesel on a cold start along with a bit of chugging.

I've plugged it in using carly and it's come up with all 6 glow plugs being faulty.

Is it likely that all 6 have gone or more likely that it's the controller?!

Thinking if the latter I'll try that first as I think it can be done without removing the inlet manifold.

Cheers

Ben

It could be both. It is possible that at some point in the past there has been an issue with one or more plugs so they were changed. Unforunately it is then common for the controller to subsequently fail shortly after.

Getting the plugs out needs great care - and judicious application of WD40 - to make sure that they don’t snap. Dealing with snapped plugs is a nightmare you do not want!

You can check each plug with a ohmmeter (for resistance) and should get between 0.5 & 2.0 ohms and room temperature. Less means a short and if much higher - or infinite resistance - then open circuit.

Guidance here....from newtis.info (copy of BMW Tech Instr)

https://www.newtis.info/tisv2/a/en/e53- ... gs/HvKVTyE

It could be the controller on its own if the plugs read OK.

Caution! Don’t test plugs with power on and out of the engine. They get to 850°C in 5 secs and will very quickly burn out as they can’t cool in the open air.

Ok. Thanks.

I'm assuming to test them I'll need to get the inlet manifold off and if I've got that far for the sake of £50 may as well change them.

Have heard of plugs snapping. Would getting my cordless impact driver on them be a bad idea? Its not overly powerfull (wouldn't undo wheel bolts for example) and It's never snapped bolts I've used it on before and is great at getting seized things undone....warm engine might be a good idea too?

Given The plugs are more of a pain I might try the controller first.

Power driven tool = NO! You need to do this by hand so you gently manipulate them to get them free.

Fully warmed engine is what the instructions linked to state is needed - along with using their ‘release agent’, which is probably WD40 with a BMW badge and 500% cost ‘uplift’

Definitely no power tools or it won't end well ,if things start to bind stop screw back in a little , spray more wd40 and be patient.

Yes they say warmed up .....easy on my sprinter van as the plugs are on top.....on X5's & X6's you have to take intake manifold off plus other bits so your gonna burn yourself as I did .....serious design problem....

The Disco guys have some handy pointers as it’s even worse if you snap them on a V6.

Try this for starters

https://www.disco3.co.uk/forum/easy-glo ... Glow+plugs

I'd avoid WD40, it doesn't have the same penetrating release such as PlusGas for example. Spray on a couple of days before you do the job. Get the car to operating temperature and use 1/4" ratchet with extension bar. You just get a feel for the glow plug releasing under torque. If it's stuck, then hang fire. If you force it and it breaks we're talking head off. The electrical resistance check is a good call first.

Soaking them in engine oil a week before is a good method - the oil thins as the engine heats and is drawn into the threads. It also resists burning off more than spray on lubricants

Ended up having to have a new starter motor on it so got the garage to do the glow plugs and glow plug module at the same time.

Its starts fine on a morning no with no white smoke and runs smoothly from the off.

Oddly, I thought I would reset the computer this morning and somehow managed 41.5mpg average on my trip to work this morning (steady, hour long A road trip with very little traffic) the previous average was 34mpg.

I didn't think glow plugs would have any impact on the MPG and to be honest wouldn't have thought 40mpg achievable in a 3,0d with a slushbox.

When we first got it I struggled getting more than 32 but this improved by about 10-15% after I changed the thermostat and gave it a full service.