EGR / DPF failure rate | Technical matters | Back Room Forum

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Mon 13 Feb 2017 21:21

EGR / DPF failure rate - notagoodname

Could anyone give me their opinion on:

- an approximate percentage probability of me having issues with an EGR valve and / or a DPF if I buy a 6-7 year old VW Sharan? Budget £10-12k.

- an approximate cost for each at a good independent garage.

The car ticks the boxes for what I need - space etc. I'd happily get a petrol but the 1.4TSI seems more problematic than the diesel.

I understand people are having issues with the EGR/DPFs etc, but without knowing the failure / issue rate I don't know if it's similar to being struck by lightening at one end of the spectrum, or getting grey hair at the other.

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Mon 13 Feb 2017 21:30

EGR / DPF failure rate - SLO76

What sort of usage do you intend? If you do mostly local stop start driving then you will run into DPF issues but as far the EGR valve is concerned it's not guaranteed to be a problem. In 22 years of buying and selling cars I've only ever suffered it once (on an old 02 Astra) believe it or not but I believe my advice to punters to avoid supermarket fuel as much as possible has proven effective here. The lady in question with the Astra admitted that she ignored my advice on go go juice and went for the cheap false economy route.

I've also personally never ran into DPF issue on any car I've ran with one (our 5yr old Polo 1.2 TDi is now the oldest) but my usage suits the characteristics of the thing and I don't trade anything with one fitted unless I'm asked specifically to source one and even then I'm very clear about the likelihood of problems and how to avoid them.

I have a couple of friends who run cars with the 2.0 TDi VAG engine you're talking about, one in an Audi TT and the other in a Golf GTD and both have had problems. The Golf though is never out of town...

Edited by SLO76 on 13/02/2017 at 21:36

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Mon 13 Feb 2017 21:47

EGR / DPF failure rate - notagoodname

Thank you for your thoughts.

Re usage:

Mixture of:

25 mile 'A' road round trips most days during week.

50-75 mile 'A' road / motorway trips most weekends.

600 mile M-way trips most school holidays.

3000 mile round trip to Germany every summer.

Average mileage 15k p.a.

Edited by notagoodname on 13/02/2017 at 21:51

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Mon 13 Feb 2017 21:54

EGR / DPF failure rate - SLO76

Should be acceptable to run a DPF equipped car then. I'd spend a bit more though and buy a good approved used VW with a good warranty though and have it maintained there or by a genuine specialist. Big part of the problem with complex modern turbocharged cars is that Joe Blogs backstreet garage has no clue how to maintain them properly.

As much as I normally talk Diesel down it's a hard sell to move on a large used people carrier without one.

Edited by SLO76 on 13/02/2017 at 21:55

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Mon 13 Feb 2017 22:10

EGR / DPF failure rate - Railroad.

I'd agree with that. The technology on modern cars, and many garages' understanding of them are fast moving in opposite directions. A good specialist with the right tools and equipment, and good technical knowledge is what you need.

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Tue 14 Feb 2017 10:03

EGR / DPF failure rate - daveyjp

On some cars EGR change is a 20-30 minute job, but it is also wise to strip down the pipework around it and give it a clean which can take much longer - youtube has plenty of videos.

As for DPF it may do 150,000 miles, it may however only do 40,000 before needing replacement, it really depends on how the car is driven and how the regen system is set up.

Replacement £500-1,000, but there are also numerous DPF sensors which can fail at any time.

As long as you buy knowing that DPF and to a lesser extent EGR valves are consumable items you will be prepared when they need replacing.

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Tue 14 Feb 2017 10:07

EGR / DPF failure rate - gordonbennet

Agreed, but remember some EGR's are buried deep and awful to get at, mk6 Golfs now gaining a reputation for presenting their owners with 4 figure sums to renew.

I have no idea how good or bad the car in question might be to work on.

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Tue 14 Feb 2017 10:49

EGR / DPF failure rate - notagoodname

Thanks again - really useful.

Is the damage done to a diesel by driving it incorrectly in any way reversible?

i.e. if I buy a Sharan with 50k miles which has done shorter trips but then it gets longer faster, hotter runs with me could for instance a slightly gummed up EGR then free off (for want of a better phrase).

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Tue 14 Feb 2017 11:29

EGR / DPF failure rate - gordonbennet

Not really, the best bet, if an EGR is easy to get at, is to take the thing off once in a while, soak it in something to soften the hard built up carbon, clean it all out and refit, some people by pass the thing altogether but i'm not suggesting you do so...i haven't.

It might help using better quality fuels, or it might even help running something like Millers Diesel fuel additive permanently (possibly another way of using high quality fuels).

The mention of Millers often brings the term snake oil into a conversation, so i'll just provide this link

www.seatcupra.net/forums/showthread.php?t=188065

make of that what you will

could using Millers help to clean an already carboned up EGR i really have no idea, whether it would help prevent further build up again i have no idea, i've used the stuff for many years and will do so for as long as i have a Diesel in the fleet, but thats only what i do, not trying to influence you or suggest it would be helpful in any way.

What i will say is that the previously well maintained 90k Landcruiser i bought a few months ago is running quieter and sweeter than when i bought it, and the engine oil is still clean and clear 500 miles after its second oil change in my care, the first change was basically to flush the oil system through thoroughly over a couple of thousand miles.

Edited by gordonbennet on 14/02/2017 at 11:34

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Tue 14 Feb 2017 11:32

EGR / DPF failure rate - RobJP

Unlikely. What you'd be doing is reducing the future rate of it 'gumming up'. You're not likely to be reducing that carbon buildup by your future driving, it's pretty well baked on.

Think of it like tartar on teeth. If a person doesn't brush regularly, then it builds up. If they then start brushing regularly, that buildup isn't going to vanish, but it will increase at a lesser rate. The only way to get it cleaned off is by going to the dentist - and the only way to get the EGR cleared of gunk is the same - but it's changed rather than cleaned.

Technically, there's no reason a clogged up EGR couldn't be cleaned. But the carbon 'gunk' is full of carcinogenic benzoates and other nasty chemicals, and in HSE legislation it would just pose a huge risk. Plus the EGR is actually moderately cheap. It's the work involved in getting to it and re-assembly that's the pain in the backside and costs so much.

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Mon 6 Mar 2017 09:13

EGR / DPF failure rate - CHarkin

Hi just read your thread and thought I'd add my pennys worth. I've been running a Sharan for nearly three years now and my driving pattern is not nearly as favourable as yours. Less longer trips more shorter trips and only half the annual mileage. No problems at all and only on three occasions have I been aware of an active DPF regeneration, you see the fuel consumption increasing for a few miles and once the idle speed was high when I was about to stop so I drove for an extra few miles.

In my opinion and its only an opinion Shell v Power + nito fuel helps greatly because it produces less soot while driving so the DPF has less work to do and the build up of depsits are reduced on both EGR and DPF, the car runs better as well.

If you drive for 20 to 30 minutes on open road after the engine is warmed up the DPF cleans itself without any input from control system, and it dosent need to be high speed or high revs. If you are worried you can have the DPF tested for "ash loading" that will give you a good idea of its condition and how much life it still has. Get a good one and you will be fine.

Edited by Charles Harkin on 06/03/2017 at 09:20

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Mon 6 Mar 2017 09:28

EGR / DPF failure rate - notagoodname

Thanks Charles - very helpful.

I went for a test drive on Saturday and was impressed with the Sharan - perfect for long motoroway trips.

Much as I'd like to stay with Toyota the bigger space of the Sharan is very appealing and with the children no doubt getting taller over the next few years, the space is only going to get more useful.

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