Stuart's Volkswagen Golf Mk 7/VII Forum

Hi

I just stumbled across your website this week when looking for DPF passive regeneration details. https://www.stuartdalby.co.uk/vwgolfmk7/dpf It's excellent. Thanks for posting!

As you might guess I was looking for Golf Mk7 details specifically, in my case an SV. I'm pretty sure I contacted VW when I bought the car but got no useful info on motorway revs and then found Skoda recommended only needing to go above 1800rpm. Wanted to double check last week but couldn't find my notes from back then so re-checked with VW customer service last week and all they replied with was "I have liaised with our Technical Support team regarding your enquiry. They have advised that the rpm is not relevant to passive regeneration. They have advised that during passive regeneration, the soot particles are continuously combusted without engine management system intervention. This usually happens when the engine is subjected to high loads. High loads occur while driving on the motorway, for example. Exhaust gas temperatures of 350°C to 500°C are then attained." Not the most useful technical reply I've ever had.

Anyway...

My engine is a 1.6 diesel, gearbox is 5 speed. Build year 2015. I know mine is a Euro 6 but also read that early Golf Mk7 1.6 diesels were Euro 5, even though EA288. Is yours a Euro 6 (ie same design and layout as mine)? I remember reading that one of the points about the Euro 6 EA288 was that the DPF had been relocated much closer to the engine so that it gets a lot hotter than in earlier designs, presumably to better enable passive regen.

So, I read your page on DPFs and see you saying back in April 2017 that 70mph (just over 2000rpm) doesn't reach 350C. Has this remained the same since? And what sort of motorways are you on? Flat or hilly? Re load on the engine.

I'm not usually in a hurry on a motorway and so actually prefer the most economical and more relaxed speed, which I found to be 63mph indicated. So I'd prefer to do 63mph or 65mph ACC except that if 70mph does passive regen I'd go with 70mph. I also wonder whether a genuine 70mph (would be indicated 73mph) would actually make it to passive regen temperature if indicated 70mph would not.

Also interesting reading your test on premium fuel. https://www.stuartdalby.co.uk/vwgolfmk7/premium-diesel Aside from I think 10 litres I've used only premium diesel (Texaco) for the sole reason of keeping the engine clean. Videos on YT seem to show that the additives included do provide some cleaning ability so I'm going to stick with premium but am going to be switching to Shell as this does seem to offer reduced soot formation and so assist with DPF lifespan. Have you found any difference between different fuels re regeneration intervals?

Interesting that you saw regens every 260 miles or so as I've seen drivers of other makes say their regens happen every 300 miles.

When your every 260 mile regen happens, does the duration vary depending on how you have driven the recent 260 miles or is it always the same (ie suggesting no point at all in trying to achieve passive regen)?

Will be trying your vehicle status page secret for spotting when I'm getting a DPF regen.

BTW, the SOC readout is no longer enabled on more recent Golfs (including mine). My dealership tech checked was told this by VW. Oddly, although almost all times I've tried it (97%+ of times I'd guess) it simply shows ___%, twice it has shown 0%.

Anyway, thanks again Stuart.

Hi again.

Sorry, hadn't spotted your "easy DPF active regen" post https://www.stuartdalby.co.uk/vwgolfmk7/dpf_regeneration Now read that and has answered a fair bit.

Seems like use Shell VPD and drive as I'd prefer at 63/65mph and leave the rest to the car.

Best

Michael

Hi Michael,

Thank you for telling me about your VW Golf. It sounds like you've found all the information you require. If you still have any outstanding questions, do please get back in touch.

When I got my Golf Mk 7 back in July 2016 I was very keen to learn about how the DPF system worked. After my initial research I was confident that my driving style was unlikely to cause any problems with the DPF. Thankfully, over 2.5 years later I appear to have been proved right. I think the car can handle most driving styles except when used primarily for short (1hour) out-of-town journeys.

Stuart

Thanks for getting back Stuart. Appreciated.

Is the >1 hour duration important? Most of my trips are just a little local (start and end of journey) with 90%+ either motorway or long distance A road. But often 3/4 hour or so. I do only 1 return local trip (2 miles or so each way) every 2 weeks plus probably another low average speed slightly longer trip average once per month.

BTW, one thing I learned only at the car's most recent (3rd) service in case you are unaware is that active regen requires at least 1/4 tank of fuel (according to the service tech) or 20 litres (according to diagnostic firm). My Golf handbook simply mentions avoiding a low tank which by implication is the 10 litre fuel warning point. Fortunately my car has 20l+ almost alf of the time, except at summer to winter diesel switchover time.

Best

Michael

Hi Michael,

Your driving style sounds fine. I don’t think you will have any problems.

I can only report from my experience and my journeys are typically long motorway/A-road cruises. My >1 hour journey time recommendation is based on the fact that when I was monitoring active regeneration, I was surprised to see it frequently start only after about 45minutes of continuous motorway cruising. I wondered why it didn’t start sooner. However, I believe it would start sooner if a previous regeneration attempt was not able to complete. Thinking about it some more now, I suspect the only driving style which would cause problems would be if all journeys were short. i.e. less than about 30 minutes when the engine would never have time to get into a state at which an active regeneration cycle could start and complete.

Thanks for telling me about the car needing to be over ¼ full for active regeneration to occur. If this is true that seems like a very high minimum fuel level since I’m sure active regeneration does not result in much greater fuel consumption. In fact I think I have checked in the past using the car’s instantaneous fuel consumption readout on the dash that it didn’t change much when active regeneration was in progress.

Stuart

Thank you Stuart. Reassuring to know.

Interesting you haven't seen it show before 3/4 hour. I had high idle revs a lot last autumn thru March but no fan on when I turned off the egnine. I wondered whether it was related to some electrical oddities I thought indicated a weak battery (and which have disappeared since a dealership gave it an overnight recharge) but then learned of the 1/4 tank required issue and around summer-winter switchover I'd been below 1/4 tank for a lot of the time. But now you mention the 3/4 hour I'll check back through my VW Connect records to see if prior to last autumn I'd been doing plenty of > 1 hour trips and from then until March not. I know almost all of the mileage I've done since mid March has been over 3/4 hour and idle revs have been fine and no fan on turning the engine off.

I agree 1/4 tank (or even more, 20 litres) seems a lot. I think it must be correct though as the dealership tech who mentioned it in passing is by far the best dealership tech I've chatted with (really top guy, very helpful, giving bits of info before asked, a problem solver) and, following that, I dropped it into convesation at an independent VAG specialist and the person there simply said 'yes, that's correct'. The 20l is something I've read when Googling re VW diagnostics and is a tank fill I can easily maintain so may as well, in case.

Re the consumption during active regen, quite a while back I switched to having my standard MFD display as MPG to try and spot regens. MPG varies so much depending on gradient that I reckon I could miss most and in fact can only recall seeing significantly reduced MPG for more than a handful of seconds on one or two occasions, both last autumn and both were obvious as soom as I was on the motorway, just over 5 minutes after starting the engine. Even brief dips only show infrequently (eg once, for I'd guess 5 seconds, last week, which I guess was LNT related).

Best

Michael

Morning Michael,

Maybe “frequently” wasn’t quite accurate. Maybe “a few times” I noticed my car start an active regen after ¾ hour into a trip. I have seen them occur sooner. Indeed, on the run described at https://www.stuartdalby.co.uk/vwgolfmk7/dpf_regeneration I knew from recent monitoring that an active regen was due and it started duly started only 15mins into the journey.

I’ve never noticed an active regen affect idle speed.

Finally, I know that during active regen the injectors fire a little squirt of fuel into the exhaust stage of each cylinder solely to raise the temperature of the DPF. This will no doubt increase fuel consumption but I think it would be negligible and probably impossible to spot using the MFD’s MPG display.

Stuart

Hi Stuart

Sorry haven't got around to replying sooner.

Since chatting with you last weekend I've used the car just twice, 5 miles or so local (all under 30mph) early in the week and then a round trip today of 20-25 miles each way today. Had the S/S switched off earlier in the week and for the out leg today. The return was the first time I'd got to check your DPF spotting procedure (bringing S/S status up on the main infotainment display). From the centre to outskirts is I guess 3 miles, doing 30mph most of the way, up to 50mph briefly, back to 30mph.

Then pretty much as soon as I hit 40mph out of town the display changed to 'engine must be switched on'. I left S/S switched on to check the revs at stop lights. Was a shade under 1000rpm, compared with approx 780rpm normally. From start to end took something like 12-13 minutes and included quite a few stops for lights and roundabouts. Throughout, watching the mpg on the MFD I'd neve have guessed a regen was on as the figures stayed decent when at constant speed. Overall trip consumption was also nothing that I would have found unusual. Tank started at, I'd guess, 19 litres or so (not sure as VW Connect updated this past week to remove the litres remaining reading. Helpful!)

If I go back 250 miles from this regen I would have been on a motorway at ACC 70mph and a large majority of miles since were the same.

So, for my experience thus far...
1) Tank does not need to have at least 20 litres but may need to be at least 1/4 full (and, given this is is what 2 decent VW techs have told me, I assume the 1/4 tank is correct)
2) 3/4 hour isn't necessary for regen to start
3) Idle revs are significantly higher during a rgen
4) ACC 70mph does not regen the DPF (a least not to a substantial extent)

Will try to keep the infotainment screen showing S/S status and see now if I get a regen at 250 miles (ish), as you do.

I wonder if the cars are geared so that passive regen can occur in 5th gear on the 1.6 at the 130kmh (81mph) recommended speed limit on German Autobahns. After all, they specifically moved the DPF much closer to the engine on the EA288 in order to get it hotter.

Best

Michael

Thanks for the information Michael. Valuable feedback. Let me know if you make any more discoveries.

Stuart

Hi. Well next time driven was today so I drove a route to check whether the regen had been successful, given that much was at 30mph and there had been several stops. Had read that the Passat B7 engine needed at least 38mph and 70C engine temp to regen and wondered whether my hitting 40mph leaving town meant the same for the EA288.
So got the car to 70C, made sure I'd done a stop start and then went onto the motorway and stuck at 60mph ACC. No regen. So upped to 70mph ACC. no regen. Which says to me that the way they moved the DPF close to the engine means the active regen will work even at 30mph steady speed flattish roads. Which is definitely good.

Best
Michael

Hi Stuart

Just got a follow up for you to the chat a couple of months back.

Around that time I switched from Texaco Supreme to Shell V-Power. I've had the stop/start info screen up pretty much all of the time, really off only in the early miles after a known regen. So, what I found...

1) VPD looks like it is possibly providing slightly better overall fuel economy for me than Texaco Supreme. I don't ever have any consistency in trips but my feeling is I'm probably getting 2-4mpg more from the VPD. The price difference means pocket wise they are about the same. However I think the economy is more variable depending on traffic conditions. I've seen mpg go north of 70mpg at the end of motorway sectors several times, which I don't recall seeing at all for at least a couple of years and I think happened much less even then. But just 10 or so minutes urban straight after can easily knock 10mpg off that figure.

2) The first regen gaps, which coincided with switching to VPD, were short. Around 100 miles, then around 150 miles. Now they've settled into a range between mid 220s and mid 270s. Possibly still lengthening (depends on the mix of roads of course) but I suspect stable. So;

3) My guess is that the firest for the first x miles VPD cleaned out significant build up. I searched for comments about VPD and found some comments expressing concern about switching to it on higher mileage cars but no evidence. Still, if you do consider switching to VPD might be worth checking first as I see your car is at least 60k miles.

4) Active regen will not start at 70mph ACC indicated (about 66/67mph GPS). In the first couple of weeks after chatting with you I noticed twice that the display changed to 'engine must be on' exactly as I decelerated from 70mph to leave the motorway. I was able to quit the exit and run at 60mph for a few minutes (perhaps not enough minutes). I think on both occasions I was between 185 and 190 miles since regen. I haven't yet discussed this with 'my mechanic' to see if it indicates eg a faulty sensor but I did read around online and found comments on there implying higher speeds were bad for regen.

The 70mph issue did however tie in with my experience last year. When I initially had the car I used to run 63-65mph on the motorway (I found 63mph seemed the MPG sweet spot and I'm hardly ever fussed about getting somewhere 5-10 minutes sooner). Only ever had 1 fan on when stopping the car, which was on a twisty hilly B road, so I switched it back on and drove straight off. Then sometime last year I switched to 70mph, based on the advice of running faster to look after the DPF. Later in the year I had frequent 1000rpm idles and S/S not working later last year and do recall them happening after motorway journeys, plus a few (2, 3, 4, 5, I forget) fan on stops soon after leaving the motorway when I couldn't simply drive off to let the car do its thing. At the time I thought it was down to the battery being on its last legs but now I'm thinking maybe a pressure sensor is not as it should be, although my low battery situation did cause strange electronic errors.

Now that I've done enough regens and refills to get a fairly stable idea of regen intervals and mpg I'm intending to do a speed test, running mainly at 70mph but dropping down 69, wait, 68, wait, 67 wait etc., every 10 miles or so when a regen is due to see if the issue is still there and at what mph/rpm it occurs. Then I can chat with my mechanic to see if this is normal or a fault.

Note it doesn't seem to affect a regen once started as I've accelerated to 70mph briefly to pass traffic during a regen and the regen has continuted.

5) I bought VAG DPF to check my DPF. Was able to take readings yesterday just 9 miles after the regen ended. My soot mass was 5.09g, which seems fairly normal according to figures posted by other VAG DPF users although clearly higher than the 2.36g you get.

6) Your interpretation of a lot of lifespan remaining down to a 2.36g residual figure in https://www.stuartdalby.co.uk/vwgolfmk7/dpf seems to be wrong. The important figure to calculate lifespan is Oil Ash Residue, not Soot Mass. VAG DPF for my car, with c.22000 miles, shows as 8.12g (10%) Oil Ash Residue. Reading around I found Skoda consider 80g to be the kaputt point and the levels others have reported per mile all seem to be generally in line with my 8.12g after 22k. So if yours is not 66k I'd guess yours should be 24g, give or take. My guess is that the DPF will deteriorate over time due to catalyst erosion or some such well before it reaches 80g Oil Ash Residue but an extrapolated 200k+ miles lifespan on the DPF for my driving style is reassuring.

7) Back to the fuel, Shell claim it is significantly quieter. I find this really difficult to judge but I would say it is quieter when on a motorway or faster A road. Not sure so much on any terrain that causes diesel clatter. I also found the same when I bought the car and used Texaco Supreme from day 1 and my guess is the dealership had used bog standard diesel.

Hope some of this helps.

Best

Michael

Hi Michael,

Thanks for your email. Lots of interesting stuff. I didn’t reply straight away because I wanted to wait until I had chance to connect my laptop with my VCDS cable and see how my car’s DPF was performing. I did that today.

Your experience of Shell V-Power sounds very similar to my own experience of trying premium diesel some time ago (See https://www.stuartdalby.co.uk/vwgolfmk7/premium-diesel ). There was a slight improvement on smoothness and perhaps some efficiency gains but cancelled out by the extra cost.

It’s interesting what you say about active regen not being triggered whilst cruising at 70mph. I usually cruise at about 57mph so hadn’t realised this. Looking back at past logs, I see that I was always travelling below 70mph when a regen started. I’m not quite sure why higher speeds wouldn’t be suitable for triggering regen.

I was particularly interested in your comments about the particulate filter’s soot mass. For comparison with your figures, this morning, before travelling my VCDS reported “Particle filter: soot mass calculated” as 4.87g and “Particle filter: soot mass measured” as 2.26g. I’m not sure what the difference between calculated and measured is. These figures are low because VCDS reported that it was only 31 miles since the last active regen finished. Since you report a “Soot Mass” figure of 5.09g only 9 miles after regen I’m guessing your “soot mass” is the same parameter as my “Particle filter: soot mass calculated”. I’m not sure whether any conclusions can be drawn from your figure being higher than mine after fewer miles since regen.

As for “oil ash residue”, I hadn’t looked into these parameters until today. VCDS reported 3 parameters: “Particle filter: oil ash volume” (0.07l), “Particulate filter: oil ash mass” (30.2g) and “Particulate filter ash load limit” (80g). The 30.2g value for oil ash mass appears to match your “oil ash residue” and appears consistent with my car now having nearly 96k miles on the clock. I don’t think the 30.2g figure it too bad. I calculate this means the DPF won’t become full until around 250k miles which is reassuring.

I’ll try to use VCDS a little more frequently in future to see how my car’s DPF is performing now compared to over 2 years ago when I last looked into this. See https://www.stuartdalby.co.uk/vwgolfmk7/dpf It will be interesting to see if regen behaviour has changed over this time.

Stuart

Hi Stuart

I've run premium diesel from the day I bought the car solely for keeping the internals clean. Read around a lot on various forums and am sufficiently satisfied that additives are beneficial, especially for the EGR (and as a + if/when I sell the car), and the cost of going via 3rd party bottles or direct through premium diesel was about the same, but with premium diesel offering a better paper trail and more reliable dosage. The extra cost compared with supermarket std diesel was such a very small % of my annual depreciation/insurance/VED/unavoidable maintenance costs that for me it was a no brainer. But premium diesel is relatively inexpensive hereabouts. I think current supermarket diesel (and one article I read about the EA288, perhaps specifically the 1.6, said solid and reliable with the only caveat being to ensure use decent quality fuel) is around 1.21 while the last VPD was 1.39. Texaco Supreme would probably be 1.33.

After reading further items earlier this year I was further sufficiently satisfied that VPD is better still re maintaining the internals and worth the 5-6p per litre extra (at most. Under Go+ I expect it will be slightly less than than this) although I expected slightly worse than before economy as the GTL component is lower energy density. So the mpg I'm seeing is a bonus. The short regen cycles after switching does seem to me to tally with it keeping the internals clean.

Your 96k does of course provide solid evidence that regular diesel is no hindrance to very good component reliability ?.


To me the 70mph issue sounds very much like a fault of some sort. Otherwise I don't see how there wouldn't be lots of 1.6TDis with rapidly failing DPFs. But will see what my mechanic says when I chat with him. I bought a CTEK charger to charge the battery as I needed to test something else and it is on there for the first time today. So, hopefully I'll be ready to try the 70-65 deceleration trigger sometime in the next week or two and can then follow up with him.


I saw the same (having both measured and calculated) when looking at Ross-Tech and it seemed an odd ting to do. I didn't look in detail as I don't have their kit. I suspect the Ross-Tech forums will have the answer somewhere. I think I read somewhere that active regens are terminated when load is somewhere between 5g and 4g. But also my last regen was shorter than usual and I wonder if my accelerating to 70mph ACC had anything to do with this and if a regen of my normal length would have given a lower mass at the end.

Yes, that's the match. So your DPF seems pretty normal according to what I've read. I think the range of extrapolated lifespans I saw from user submitted data was mainly in the lower half of the 200s. Of course, the oil ash is only one determinant. One of the other things I think you wrote about was the fan coming on when stopping, interrupting a regen. I've seen comments about this possibly causing the DPF to crack because of the very high temperatures so unless I absolutely must stop in a situation like that I start up and get moving again. But then I'm the sort of person who leaves the engine idling briefly at the end of any drive to avoid turbo glazing even though it's been suggested the turbos on Mark VIIs have a cooling circuit to solve this.

Best

Michael