Over heating 170 TDI

[Spiney]

Hi Peter VW

My point is that regen (I beleive) requires the engine to be ON, if it's off then the DPF cylce ain't happening!

[peter.vw]

Hi Peter VW

My point is that regen (I beleive) requires the engine to be ON, if it's off then the DPF cylce ain't happening!

Hi Spiney
Not having a complete understanding of the mysteries of the system I am taking it that the fans run to help dissipate the heat from under the bonnet,
You can certainly smell the hot steel from outside the car. It may have been more noticeable with my car as it may have been doing it for the first time.
I think also you would not know it was happing if you was on a long run but I had only done 6 ½ miles then stopped.
I think its normal for the fans to run on when switched off if the engine is hot, other cars i have had do this to help cool the system down.

[Digiman]

Hi Peter VW

My point is that regen (I beleive) requires the engine to be ON, if it's off then the DPF cylce ain't happening!

Hi, If the Regen is doing its business as you are driving you probably won't notice it. However as the engine runs hot while it is working then when you stop the car like I did at my house the engine temp would still be very hot and the fan would stay on to cool the engine down.

Try this carefully:-

When the car is idling after say a run when the engine is at normal temp and no Regen taking place. Lightly hold your hand about a couple of inches from the exhaust and feel the exhaust gas temp.

Now when the Regen is taking place and you stop the car and leave it idling, do the same thing (very carefully) and check the difference in exhaust gas temp (it should be extremely hot). This is a sign that the Regen is taking place.

All that soot has to go somewhere and as it aint coming out of the exhaust (just check with you finger, when the car is cold, how clean the inside of the exhaust is).

[alanstead]

On a slightly different note, the TDI Rocs also have an electric auxiliary water pump which can run when the engine is switched off. Presumably this is for when you have got home and the car is in the middle of regen and the engine is super hot and therefore needs to keep pumping the coolant through the system to aid cooling of the engine. This would make it much more efficient as on older cars when you stop and there hot, the fan runs, but the water in the rad is not circulating as the water pumps are mechanical, so its only cooling the rad.

[Malcolm]

Assuming vehicle is brand new - heres what you do:
The fault was obviously there from new so ask for the DP (dealer principle) and simply tell him you are going to reject the car.
If its on finance advise the finance company.
You have 6 months, ANY fault such as this which is proven its looked upon as being there since new and thus they must replace or refund. If you turned it around and said with a bit of service you may actually not wish to return the car I think you'll find the DP's own keys coming out very fast!

[ABN1C]

I don't think there really is a fault here Malcolm, as it happens with a number of people's cars and does mention it in the manual.

[trix]

as ABN1C says the DPF regen occurs for all diesels & is sometimes thought to be a fault but if the journey ends before the regen completed it will continue possibly in the manner alan mentions above.

but in the case of Peter in the original post there may possibly be something else but that is up to the dealer to resolve, it is not affecting the cars performance (it still goes) therefore rejecting the car (or threatening to) is not the answer, it won't fix it. the dealer needs to determine what is wrong & resolve to peter's satisfaction. rejecting the car (or threatening to) is an extreme measure & imo would strain relations so if you wanted to use the dealer again I wouldn't advise it

& I would think peter is enjoying the car in pretty much all other respects.

S

[peter.vw]

Hi once again I am amazed at the information and level of the professional advice on this forum.

The advice of Digiman and ABN1C I think is right, that’s not to say that other comments don’t have validation as with Malcolm, if this was a unacceptable problem is nice to know your rights.

I once for my sins use to be a motor mechanic and also run a workshop repairing HGV vehicles so when all these things happened to a brand new car I was alarmed.
Needles to say when I was repairing and rebuilding 8 Litre diesel engines particle filters had not been thought of, blue black smoke and a heavy diesel knock was the norm.

So yes high engine temperature and the smell of hot steel when the vehicle is in regen is a good explanation of what I experienced,
And yes Trix your right I am enjoying my Roc never thought that it would have been possible to get the performance and smooth running from a Diesel, would recommend the TDI 170 to any one.

Interesting to see the addition of an auxiliary electric pump to assist cooling when the engine is off, take it this is for race vehicles or is this for road going cars too?

[Richard A]

peter.vw, commiserations regarding your experience at the hands of what sounds like a very rubbish dealer.

I think digiman is on the money here. I also think that if the fan runs on for 7 minutes or so after the engine has stopped (and the water pump has stopped pumping) then the rad could be cold. There was one thing I wanted to ask out of interest, what sort of figures were you seeing on the temperature gauge? You mentioned in your opening post that there are times when the temperature gauge will plummet, I was wondering what through what sort of range on the scale the plummeting was taking place... from near the red to normal?

[peter.vw]

peter.vw, commiserations regarding your experience at the hands of what sounds like a very rubbish dealer.

I think digiman is on the money here. I also think that if the fan runs on for 7 minutes or so after the engine has stopped (and the water pump has stopped pumping) then the rad could be cold. There was one thing I wanted to ask out of interest, what sort of figures were you seeing on the temperature gauge? You mentioned in your opening post that there are times when the temperature gauge will plummet, I was wondering what through what sort of range on the scale the plummeting was taking place... from near the red to normal?

Hi thanks for commiserations I look at it this way I got a very good discount buying the car (9%) now when the dealer should be clawing some of the cash back in servicing and extras he has now lost out. I have three VW agents around here so I just take my trade elsewhere.
On the temperature thing this is a result of the DPF going into regen, I don’t know if the management system can control the thermostat but I have seen the temperature gauge drop from 100 to 50 and this seemed to be at the end of the regen process and not repeated.
Normally it takes 6 to 8 miles to reach normal temp (85) but in regen you can half that.
I have seen similar posts on this subject on the sister forum to this one scirocconet and they seem to come to the same conclusions

[andres]

This had also happened to me on two or three occasions, when the car was new. I dont think its a problem, as it hasn't happened in the last 15.000 mi, IMO Regen is a good theory

[peter.vw]

Now I have been driving the car for some time I noticed that Re-gen is approximately every 400 miles with the kind of journeys I do

[MareQ]

I had such a thing in my 170HP TDI few time (3 or 4, car is now 8.000km). I spoke with a friend of mine who works for VAG for 10 years time and said it is nothing to be worry about - typical in TDI engines.

[sj968]

Ive had the fan run for around 5 minutes after a motorway stint at high speed. Ive also just had a sooty smell come from the car after a fast run on country roads, into the interior of the car. After I got back I noticed the car idlying abit higher than normal (around 1950). I guess this is the DPF burning soot out? Exhaust seems to be very hot. I was surprised the smell came into the car, I thought it was the Citroen in front but after I overtook it seemed to remain! Will wait to see if happens again...