Glowplug question

[jopparocks]

The glowplug light on my dashboard goes out ok when I turn the ignition to the correct setting and wait a few seconds and I then go ahead and start the engine but it comes on again for a few minutes when the engine is up and running then goes out again. Is this a problem and should I get the plugs checked or is it normal and not something to worry about?

 

[Phill D]

Hi, no that's not normal and certainly not at this time of year.
I would suggest you get it scanned it could be 1 or more of the glow plugs or even a harness / sensor issue.

 

[jopparocks]

Hi, no that's not normal and certainly not at this time of year.
I would suggest you get it scanned it could be 1 or more of the glow plugs or even a harness / sensor issue.

Thanks Phil. The engine is a 1997 2.8 Mercedes on my Hymer s650. Are they easy to check myself or do you think it should go into a garage?

 

[Silver-Fox]

Have you plugged a scanner in to see if there are any faults logged?

Might give you a pointer.

I had a Vivaro van and the glow plug would light up if the diesel filter needed water draining from it.

 

[Slippymurphy]

I’d go to garage get it plugged in to a diagnostic thingy that should bring up faults on the plugs/sensors etc
Ps I’m not a mechanic just a wee disclaimer

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[jopparocks]

Have you plugged a scanner in to see if there are any faults logged?

Might give you a pointer.

I had a Vivaro van and the glow plug would light up if the diesel filter needed water draining from it.

Can a scanner be used on such an old van? Its already in for some body work repairs so might ask them to have a look at this as well.

 

[Silver-Fox]

Can a scanner be used on such an old van? Its already in for some body work repairs so might ask them to have a look at this as well.

I know some early vehicles had obd ports.

If not there was a way of connecting some wires together and you get flash sequences on the dash.

Worth asking whilst it’s in I’d say.

 

[Rapido925M]

Same problem with my 2002 Merc. I drove 3k miles on it but was always concerned that it wouldn’t start.
Eventually I put it into the garage who confirmed 2 glow plugs not working. The engine had to be dropped out (Aclass) as the plugs wouldn’t come out; they also replaced the clutch and dual mass flywheel (change of spec from the original so it took a little longer than expected). £1800

 

[Phill D]

As a 1997 I would them checked out. I don't know the engine so I am sorry I don't know how difficult it may be to get them out.
One problem often encountered with older glow plugs is that they get brittle with age and can snap off in the head.

Don't wish to be doom and gloom but if you have a trusted garage then get them to check them out for you.

 

[gus-lopez]

Have you plugged a scanner in to see if there are any faults logged?

Might give you a pointer.

I had a Vivaro van and the glow plug would light up if the diesel filter needed water draining from it.

As said the glow plug light is often used to indicate other faults when engine is running.

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[jopparocks]

As a 1997 I would them checked out. I don't know the engine so I am sorry I don't know how difficult it may be to get them out.
One problem often encountered with older glow plugs is that they get brittle with age and can snap off in the head.

Don't wish to be doom and gloom but if you have a trusted garage then get them to check them out for you.

What problems can it cause if a couple of them are knackered? Is it a case of a stitch in time saves nine

 

[jopparocks]

As said the glow plug light is often used to indicate other faults when engine is running.

Thanks Gus, just saw your post which answers my latest question.

 

[Crazylegs]

What problems can it cause if a couple of them are knackered? Is it a case of a stitch in time saves nine

We had the same problem with a ten year old Mercedes car, the Mercedes garage assumed one or more plugs would snap whilst being removed and quoted £1600, can’t remember if that included Vat or not. Our local garage really wasn’t keen to do the job and advised us to keep on driving as the vehicle would still start, which we did without issue.

 

[mitzimad]

glow plug light is illuminated for a lot of faults not necessarily the glowplugs get the codes first before playing parts darts

 

[jopparocks]

We had the same problem with a ten year old Mercedes car, the Mercedes garage assumed one or more plugs would snap whilst being removed and quoted £1600, can’t remember if that included Vat or not. Our local garage really wasn’t keen to do the job and advised us to keep on driving as the vehicle would still start, which we did without i

glow plug light is illuminated for a lot of faults not necessarily the glowplugs get the codes first before playing parts darts

Good to know.

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[Bessy765]

First thing I would do was to change the fuel filter, if the paper element type make sure the bowl is clean, on some models the light comes on if there is water in the filter. When starting from cold does it start easily? If even one plug is u/s it will effect how it starts.

 

[jopparocks]

First thing I would do was to change the fuel filter, if the paper element type make sure the bowl is clean, on some models the light comes on if there is water in the filter. When starting from cold does it start easily? If even one plug is u/s it will effect how it starts.

Hi Bessy, even in the coldest weather once the glowplug light goes out it starts no problem.

 

[Scotch mist]

Hi Bessy, even in the coldest weather once the glowplug light goes out it starts no problem.

The glow plug in my Renault master continues to heat long after the light goes out , 12 seconds comes to mind , I found this out when it got harder to start , I thought it was glow plugs but turned out to be a fractured fuel pipe

 

[Bessy765]

Some earlier Fiat models with a blue box housing the relay for the glow plugs, developed a fault similar to yours, when the glow plug light goes out the current is still supplied to the plugs the light only goes out after a set time according to the outside temp. The drop in voltage caused by the operation of the starter motor and the rise in voltage when the alternator starts charging for some reason caused the relay to operate the glow plugs again. In some cases the plugs would eventually fail. But I think that was on earlier models than yours.

 

[Mr and Mrs O]

We had a 2012 merc sprinter the col light came on 4 years ago still started fine in the summer but when the weather cooled it would turn over a few times before firing up. Apparently its the luck of the draw according to the garage whether the glow plug snap on removal so i gues check everything else first.
May just be a loose connection

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[Bessy765]

Worth a try, turn ign on till glow plug light goes out, turn key off then immediately turn on and start the engine, this may stop the relay getting hot the operates the plugs. See if that makes any difference?

 

[St3v3]

Thanks Phil. The engine is a 1997 2.8 Mercedes

On our old 1996 sprinter the situation you describe says one or more of the plugs isn't doing what the module would expect. Common fault is the multiplug from the module that goes out to the plugs has tube type connectors that need cleaning and squeezing back together.

That's an easy fix, but sadly it's also entirely possible a glow plug(s) has died.

You need a multimeter and someone sensible to do some easy tests.

 

[jopparocks]

Worth a try, turn ign on till glow plug light goes out, turn key off then immediately turn on and start the engine, this may stop the relay getting hot the operates the plugs. See if that makes any difference?

Will definitely give that a try Bessie

 

[hymerman]

If it starts OK, then leave well alone.
My old Merc glow plug light stays on permanently ,but the van starts fine .
They have a habit of snapping whilst trying to remove them resulting in a huge bill, hence lots of garages will refuse the job.

 

[St3v3]

If it starts OK, then leave well alone.
My old Merc glow plug light stays on permanently ,but the van starts fine .
They have a habit of snapping whilst trying to remove them resulting in a huge bill, hence lots of garages will refuse the job.

Maybe you should add "If it starts OK in deepest winter" lol

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[hymerman]

Hi St3v3,
I agree , but its been like that for 7 years and never missed a beat starting even in the coldest or dampest winters.
I 'd leave well alone until the winter and see.
Massive bill if one snaps on removal and maybe didn't need to be done.

 

[Phill D]

I had no option to have my wife's passat glow plugs donea few weeks ago. The estimated cost was £120 for all 4 replaced.
The final bill as a result of an issue was £385.
And yes I trust the garage and I was shown the problem when they realised that there was a problem.

 

[St3v3]

Hi St3v3,
I agree , but its been like that for 7 years and never missed a beat starting even in the coldest or dampest winters.
I 'd leave well alone until the winter and see.
Massive bill if one snaps on removal and maybe didn't need to be done.

Good stuff. I should have said you are quite right about them liking to snap.

 

[Silver-Fox]

I had no option to have my wife's passat glow plugs donea few weeks ago. The estimated cost was £120 for all 4 replaced.
The final bill as a result of an issue was £385.
And yes I trust the garage and I was shown the problem when they realised that there was a problem.

Bargain I’d say considering what it could of cost

Seems cheap at that for 4

 

[Phill D]

I am very competent with vehicles especially mechanically and glow plugs is a job I like to pass on!

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