2014 Hyundai Santa Fe - Sooty back end

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Tue 1 Nov 2016 12:52
2014 Hyundai Santa Fe - Sooty back end - SWD

I have a 2014 Santa Fe 2.2 197 auto (diesel) that has a DPF.

The car gets a sooty boot and the exhaust pipes are black.

I’ve had the car from new, always serviced it with Hyundai at 10k intervals and it is currently on 33k.

I get no dash light and no poor running or loss of power or economy.

It has been to the dealer 3 times and the last visit they said that it was fine, that there is no faults recorded and it will pass a mot test and is therefore within acceptable limits and no fault is recognised by Hyundai.

I cannot see how a DPF car can get a sooty boot and be within “acceptable limits”…

Any guidance gratefully received.

Thanks

Edited by SWD on 01/11/2016 at 12:54

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Tue 1 Nov 2016 13:11
2014 Hyundai Santa Fe - Sooty back end - Railroad.

Diesel engines are oil burners. Don't let the fact that the car and the engine are fairly new allow you to lose sight of that fact. Diesel fuel is oil, very much the same as heating oil, and your engine burns it. The exhaust will get black and sooty and there's nothing you can do to prevent it other than to stop using it. The DPF stores particulate matter when driving at slower speeds, ie around town, and regenerates to clear the DPF when driving conditions are more favourable. So DPF or not your exhaust will still get sooty. The DPF doesn't solve the emission problem. It merely allows for the problem to be moved to a place where the harmful effects of diesel combustion are less critical.

Edited by Railroad. on 01/11/2016 at 13:21

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Tue 1 Nov 2016 13:12
2014 Hyundai Santa Fe - Sooty back end - RobJP

I suspect the sooty tailgate/bumper on your car is more to do with the aerodynamic flow in the area, or possibly active regenerations of the DPF.

DPFs don't remove ALL particulates. A commonly given figure is 80% reduction (AA).

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Tue 1 Nov 2016 20:58
2014 Hyundai Santa Fe - Sooty back end - Falkirk Bairn

Run it on 2/3 tankfuls of Shell V power diesel & see if that cleans up the exhaust output,

An extra investment of less than £20 might throw light on something - after all when the car was a brand spanker you did not have the problem you seem to have just now.

My Xtrail diesel ran quieter & smoother on V power & marginally better mpg.

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Wed 2 Nov 2016 19:37
2014 Hyundai Santa Fe - Sooty back end - SWD

I always use vmax when I can, so not sure that will help, but thanks for the info.

I do approx 20k a year, maybe 15k ish on the motorway, so it's not like I'm doing lots of short journeys to clog things up...

As to 80% not sure that's true.

All the dpf specialists that I have spoken with have told me that I should have no soot.

Equally the Hyundai garage verbally told me that Hyundai euro have not experienced this issue before.

I think that the car has a defective dpf. The mot smoke test that has been used to say the car is ok will also pass a car that has had a dpf delete. So that gives me no confidence.

Basically I think that they have plug in the "computer" and it has said "no problem".

I understand that it's hard to detect mechanical problems in this day of computers having all the answers....

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Thu 3 Nov 2016 08:19
2014 Hyundai Santa Fe - Sooty back end - Railroad.

At the end of the day the DPF is only a filter, and so other than becoming blocked there really isn't much else that can be faulty about it. Whilst I do not know the exact figure, I do know that not all of the particulate matter collected in the DPF can be broken down small enough to be able to pass through it during the regeneration process. Eventually it will become blocked, and will need replacing for this reason.

Diesel engines produce soot, and so if it's not emitted from the exhaust where will it be?

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Thu 3 Nov 2016 09:24
2014 Hyundai Santa Fe - Sooty back end - RT

At the end of the day the DPF is only a filter, and so other than becoming blocked there really isn't much else that can be faulty about it. Whilst I do not know the exact figure, I do know that not all of the particulate matter collected in the DPF can be broken down small enough to be able to pass through it during the regeneration process. Eventually it will become blocked, and will need replacing for this reason.

Diesel engines produce soot, and so if it's not emitted from the exhaust where will it be?

The hotter the exhaust, the smaller the particles - the same applying to petrol engines but their exhausts are hotter, so smaller particles, but the reason why future petrols will need DPFs as well.

A DPF regeneration, whether passive or active, is intended to increase the exhaust temperature, producing smaller particles which can pass through the DPF - if this is done at the right frequency there's no reason a DPF won't last forever.

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Thu 3 Nov 2016 12:42
2014 Hyundai Santa Fe - Sooty back end - RichardW

You're a bit confused about the DPF, Railroad...

Yes, it catches the soot, but when it regens it does not just throw it out of the back - it effectively burns it. A tail pipe on a DPF car should be clean - my 120k 307 1.6 HDi is still virtually clean.

If the regen cycle does not complete fully, then it will become blocked (hence the warnings about not using them for too many short runs, or taking them for a decent run if the warning does come on). However, the process of regen doesn't manage to burn everything (particularly on those that are equipped with an additive, eg PSA, where the additive forms ash) and this steadily builds up in the DPF till it needs to be cleaned or replaced. This situation is made worse if low ash / SAPS oil is not used as the engine oil blowby causes a much faster build up in the DPF.

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Thu 3 Nov 2016 13:09
2014 Hyundai Santa Fe - Sooty back end - Railroad.

Diesel particulate matter also consists of sulfate, nitrate, various metals and other trace elements, not all of which can either burn nor pass through the filter. A salesman might like to tell us at the point of sale that a DPF should last forever, but the reality is they probably won't.....

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Thu 3 Nov 2016 13:22
2014 Hyundai Santa Fe - Sooty back end - RT

You're a bit confused about the DPF, Railroad...

Yes, it catches the soot, but when it regens it does not just throw it out of the back - it effectively burns it. A tail pipe on a DPF car should be clean - my 120k 307 1.6 HDi is still virtually clean.

If the regen cycle does not complete fully, then it will become blocked (hence the warnings about not using them for too many short runs, or taking them for a decent run if the warning does come on). However, the process of regen doesn't manage to burn everything (particularly on those that are equipped with an additive, eg PSA, where the additive forms ash) and this steadily builds up in the DPF till it needs to be cleaned or replaced. This situation is made worse if low ash / SAPS oil is not used as the engine oil blowby causes a much faster build up in the DPF.

Which needs the OP to be sure that ONLY 5W-30 ACEA-C3 oil has been used - the ACEA-C3 being the important part as other specifications would likely cause the conditions he describes.

When Hyundai brought out the Euro 5 2.2 diesel in 2010 (very different engine to the previous 2.2) the need for 5W-30 ACEA-C3 was clearly documented but a number of dealers continued using the wrong oil and owners had to involve Hyundai UK to get FOC oil changes done to correct the matter. It shouldn't still be happening at franchised dealers but it can't be guaranteed and independents may not be up to speed, but should be.

Problem is that too many people just look at the viscosity and ignore the ACEA requirement.

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Sun 6 Nov 2016 11:36
2014 Hyundai Santa Fe - Sooty back end - sandy56

Have you ran it at speed for at least an hour? Try to get the whole car exhaust HOT by running on the motorway, maybe in a lower gear than usual. If that doesnt help clear the exhaust then it needs a proper investigation. If the dealer cant help try Bosch servcie centre. They usually have all the kit to check modern diesls, and some have a rolling road.

Black smoke tends to suggets over fuelling- running a bit rich?

Maybe someone better informed than me can confirm?

I have an old MB 636 diesel about 45 years old- it doesnt smoke, and it doesnt have a DPF.

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