Glow plugs failing

[DRLee]

Hi all

Our Bongo (diesel) seems to have developed an annoying repeat habit of killing off glow plugs. In the first instance we had a starting problem which our local mechanic diagnosed as dead glow plugs, and sure enough once he had replaced them all was well for about 3 months - starting sweetly every time without the weapons grade clouds of smoke .

Unfortunately starting then became a bit erractic again, so back to the garage who again diagnosed a couple of dead glow plugs (our friendly neighbourhood mechanic replaced the plugs FOC as they were within the manufacturers warranty). Again, all was well for about 6 months after this, but unfortunately the fault re-occured, so our mechanic this time replaced the plugs with a different brand.

These new plugs were fine for about a year, but guess what, we are now back to somewhat erratic starting and clouds of smoke. Our mechanic has again replaced a (single) faulty glow plug under the manufacturers warranty, but is really scratching his head as to why this keeps happening. He has been fitting plugs by ADC / Bluepoint and Nippon which apparently are good quality brands and the correct specification.

Has anyone else had this problem and if so, what was the answer?

Thanks in advance

[missfixit70]

NGK plugs seem to be the ones to go for, a lot of other makes don't seem to cut it.
Could it be hat the glow plug relay is not switching the plugs out as it should & thus leaving them on all the time? There's a factsheet in the members area on glowplugs & their operation that may help with a useful little mod to be able to turn off the glowplugs once runnning.

[missfixit70]

Or maybe it's not the plugs at all but an iffy glow plug relay or fusible link? How was it ascertained the glow plugs had failed?

[Northern Bongolow]

a new fan switch next to the starter motor in the head may also be of use as this is the temp sensing point that the glow plug circuit uses to dictate (via the ecu) how long they stay on, or how often.

tip. use the gen mazda part imo.

[DRLee]

Thanks guys.

I'm not sure how our mechanic tests the plugs, but apparently the first replacement set were put down by the manufacturer as being a dodgy batch. Will ask our garage about the glow plug relay as a possible root cause, but wouldn't the dashboard light remain on if the plugs weren't being switched out? The light does go off as expected along with a faint but audible clunk, which I presume is the relay engaging. Will also follow up the fan switch as a possibility.

[francophile1947]

but wouldn't the dashboard light remain on if the plugs weren't being switched out?

No - they can work for quite a while after the light goes out and the engine starts. Something designed to cut the emissions until engine reaches required heat.

[teenmal]

Hi all

Our Bongo (diesel) seems to have developed an annoying repeat habit of killing off glow plugs. In the first instance we had a starting problem which our local mechanic diagnosed as dead glow plugs, and sure enough once he had replaced them all was well for about 3 months - starting sweetly every time without the weapons grade clouds of smoke .

Unfortunately starting then became a bit erractic again, so back to the garage who again diagnosed a couple of dead glow plugs (our friendly neighbourhood mechanic replaced the plugs FOC as they were within the manufacturers warranty). Again, all was well for about 6 months after this, but unfortunately the fault re-occured, so our mechanic this time replaced the plugs with a different brand.

These new plugs were fine for about a year, but guess what, we are now back to somewhat erratic starting and clouds of smoke. Our mechanic has again replaced a (single) faulty glow plug under the manufacturers warranty, but is really scratching his head as to why this keeps happening. He has been fitting plugs by ADC / Bluepoint and Nippon which apparently are good quality brands and the correct specification.

Has anyone else had this problem and if so, what was the answer?

Thanks in advance

Hi DRLee,

It might be worthwhile getting your mechanic to fit a test lamp to the glow plug feed to monitor the operation of the supply.Your mechanic sound like he is interested in your problem.

Cheers..

[DRLee]

Your mechanic sound like he is interested in your problem.

Yes, Gerry at Southfield Garage (Paignton) is a great bloke to deal with and has serviced my cars for over 10 years now. He has owned a couple of Bongos himself, so does know many of their foibles.

[321Away]

use only NGK plugs, have fitterd various others including bluepoint and in my and many others NGK give best performance and life, the plugs stay on for abt 15 seconds including the 5 the coil light is on and come live when cranking, and for a short period after starting, get the mechanic to check they are switching off and not burning themselves out

Julian

[haydn callow]

I fitted a illuminated switch into my relay feed....you would be suprised how long the plugs stay on after the engine has started.....they can cycle on/off many times before the operating temp is reached and they finally stop......the "glow coil" warning light means nothing and is not even in the glow plug circuit.......not really suprising they fail quicker than most....there is a fact sheet on adding the switch mod and it means you can switch the plugs off when running smooth....also a bit of a anti theft device... However remember to switch back on before starting.

[Alacrity]

I agree with the above about NGK. I fitted other makes mentioned here & they didn't last long, so far (over 12 months now) the NGK's have been fine.