Mercedes Vito 3.0L Diesel

[TillRollGuru]

Hello i have just purchased a Mercedes Vito with 186000 miles on the clock.

The glow plug light has came on within the last 100 miles.

Some mornings the van will struggle to start and the glow plug will come on. The van will start and seems to run absolutely fine asides from this issue.

Sometimes the light will go off when driving the van. After enquiring about a change with few garages nobody wants to mess with the glow plugs on the van. Apparently prone to snapping.

I've been advised to get a fuel filter for the van also

Could anyone advise on these two things?

 

[Numair Aidroos]

Hello i have just purchased a Mercedes Vito with 186000 miles on the clock.

The glow plug light has came on within the last 100 miles.

Some mornings the van will struggle to start and the glow plug will come on. The van will start and seems to run absolutely fine asides from this issue.

Sometimes the light will go off when driving the van. After enquiring about a change with few garages nobody wants to mess with the glow plugs on the van. Apparently prone to snapping.

I've been advised to get a fuel filter for the van also

Could anyone advise on these two things?

Yes, both are required. Glow plugs may snap, but there are methods to ease their removal and replacement. After 186K mileage, there is more to the whole car which will need replacement and refurbishment. The list is too long.

For me it was glow plug number 5 and 6 after if I recall correctly at 80K Kilometre mileage. They used some solvent and ran a few tests on the star to confirm and took it from there.

I'm certain the members here will recommend indie workshop in your area who will take up this challenge. If all else fails just head over to any Mercedes-Benz dealer.

 

[91dm]

Ideally you need someone to check the codes and find out which is the problem and the relay is ok before starting to tear into it. We have had good luck with warming the engine before work and soaking the hole in fluid. It would be no harm to give the engine a full service at the same time.

 

[BTB 500]

Hello i have just purchased a Mercedes Vito with 186000 miles on the clock.

The glow plug light has came on within the last 100 miles.

Some mornings the van will struggle to start and the glow plug will come on. The van will start and seems to run absolutely fine asides from this issue.

Sometimes the light will go off when driving the van. After enquiring about a change with few garages nobody wants to mess with the glow plugs on the van. Apparently prone to snapping.

I've had my 2007 one from new, currently on 138k miles - glowplugs started failing at under 50k miles but this never really affected starting. It may well be the glowplug relay that's failed, in which case none would be operating. As above a decent garage will be able to read the fault codes ... the MB STAR system identifies which specific plug(s) need replacing if that's it.

I actually have exactly the same issue as you at the moment (cold starts taking a lot of cranking, glowplug light coming on), and have mine going in next week.

 

[m80]

As above I wouldn't expect glow plug issues to affect starting unless you are in sub zero temperatures.
Pre treatment of the plugs with plus gas over a week is a common recommend before attempting removal. Spray, run engine to temp, same the next days.
Tease the plugs in / out until they are happy to come out.

For the starting I would do a leak off test of the injectors, the fuel pressure may be slow to build and that would affect starting.
If the injectors are on the way out expect a hefty bill of upwards of £1,600 for the 6, refurbs aren't really worth having imo.

 

[BTB 500]

For the starting I would do a leak off test of the injectors, the fuel pressure may be slow to build and that would affect starting.
If the injectors are on the way out expect a hefty bill of upwards of £1,600 for the 6, refurbs aren't really worth having imo.

Gulp. Would that only affect cold starting though? If I drive somewhere the engine starts OK when coming home.

 

[BigJase88]

Check the glowplugs

You should be looking at a reading of circa 1 ohm between top of glowplug and engine earth / metal

You will have to unplug all glowplugs 1st

If any are open circuit they will be your issue

The glowplug that are open circuit will need replaced this is your issue on cold starts in the morning

Not sure how many cylinders you have
Say 6? So on a cold start it will only start on say 4 or 5 cylinders and the ones with knackered glow plugs will eventually join the party when that cylinder has enough heat from the rest

I would certainly be changing the knackered ones

 

[BTB 500]

Not sure how many cylinders you have
Say 6? So on a cold start it will only start on say 4 or 5 cylinders and the ones with knackered glow plugs will eventually join the party when that cylinder has enough heat from the rest

Yes it's a V6. I've not noticed any difference in the past with a failed glowplug, even well below zero. The poor cold starting on mine came in quite suddenly, which is why I'm hoping it's the relay rather than the injectors.

 

[m80]

Gulp. Would that only affect cold starting though? If I drive somewhere the engine starts OK when coming home.

Possibly yes,
but a leak off test seems like a good place to start.

If it's running well after the cold start, and the leak off is excessive, I would be tempted to monitor.
But Star can monitor the fuel pressures during a start and might well diagnose something else such as fuel pump. The trouble with your issue is that by the time you get it to an indie it'll be warm.

These aren't known for air ingress like the earlier MB's so that seems unlikely.

After thought,
Torque on an Android can monitor the fuel pressure, when cold for you. You would need be sure Torque has connected via the BT sender 1st though.
That way you might see the low build up of pressure during the 1st cold start.

 

[BigJase88]

Yes it's a V6. I've not noticed any difference in the past with a failed glowplug, even well below zero. The poor cold starting on mine came in quite suddenly, which is why I'm hoping it's the relay rather than the injectors.

You maybe only had 1 failed glowplug and now you have 2 so harder to start

 

[BTB 500]

You maybe only had 1 failed glowplug and now you have 2 so harder to start

It doesn't sound like it's firing on any cylinders though. It starts and runs quite normally ... just requires a lot more cranking than usual before this happens. With a failed relay none of the plugs would be working, so all the cylinders would have to warm up through compression before firing. Or as m80 said it could be a fuel supply issue. Or both, of course!

 

[BigJase88]

It doesn't sound like it's firing on any cylinders though. It starts and runs quite normally ... just requires a lot more cranking than usual before this happens. With a failed relay none of the plugs would be working, so all the cylinders would have to warm up through compression before firing. Or as m80 said it could be a fuel supply issue. Or both, of course!

Yeah i get you will crank and crank until enough heat generated

At that mileage i would still be checking the plugs as a matter of course.

Such a straight forward test

 

[BTB 500]

I know for sure I have a failed plug - it's been like that for some time as the MB dealer it went to didn't want to replace it at the previous service! Apart from the usual seizing/snapping issue access to some of them is very tight in the Vito.

 

[BigJase88]

I know for sure I have a failed plug - it's been like that for some time as the MB dealer it went to didn't want to replace it at the previous service! Apart from the usual seizing/snapping issue access to some of them is very tight in the Vito.

Pretty shoddy from the dealer to be fair

Big scaredy cat

 

[91dm]

It could be one of the plastic fuel pipes starting to let air in passed the o ring causing the fuel to fall back and that first cranking is priming up.

 

[BTB 500]

Well all I got from the dealership was that the #3 glowplug was failed. I told them that had been the case for at least a couple of years and the poor starting was a recent thing, but they said they couldn't (or wouldn't?) do any further diagnostics until the plug had been replaced. We needed the van back today (they'd had it since Wednesday) and couldn't afford any complications/delays with the plug replacement, so it's been left for now. Useful to know it still only has a single failed plug though. It's going to a local garage on Monday to have the front springs replaced (the dealer couldn't do this as MB ones are currently back-ordered with no ETA) ... will see if they can look at the starting as well.

 

[BTB 500]

So my local garage reported that two plugs are out (cyls 3 & 5), and there's an error logged for the relay. They're ordering the parts in and will fit them in approx. 3 weeks ... currently waiting for their vibro gun to be fixed. Remains to be seen if this will make a significant difference to the starting but they need doing anyway.