Engine smell oil/exhaust & Auto express report

[CJT53]

To all,

More on VW Golf 2.0 TDI DPF GT Sport 5dr recent purchase. O.k. while the Golfs in the garage & waiting for the repairs to the gear shift problem (from previous post) I thought I would try to iron out two further queries I've noted. On an old service record, it reads, "full BG engine clean as vehicle was found to have contaminated oil" then reads, after this was done, the bad oil smell was gone. Prior to purchase, I did ask the previous owner what this was about, but no real definitive answer, but I did speak to the service people & they said it was to do with carbon build up & inferred the engine oil could have been changed sooner. (Oil & filter changed on that service record October 2015)

Anyway I have noted sometimes, it does still smell when down wind, I would say typically a smell associated with diesel engines. I've read things about the DPF (diesel particulate filter) as well when they're meant to self clean, but not too sure, so was wondering if this could be anything else or underlying item that I should investigate further.

I read an article by Auto Express back in the day when the Mk5 was released, it reads "the start up rattle & noise means the TDI isn't as refined as the petrol Golf" O.k. yes we all get that & having had a Mk4 Golf GT TDi 150 before this one, but would say the Mk5 does seem to have more diesel rattle at idle, however when on the move, say over 30mph, it's less evident & seems a quiet ride. Any takers on this one for more info ?

Over & out,
CJT53

[CJT53]

To all,

More on VW Golf 2.0 TDI DPF GT Sport 5dr recent purchase. O.k. while the Golfs in the garage & waiting for the repairs to the gear shift problem (from previous post) I thought I would try to iron out two further queries I've noted. On an old service record, it reads, "full BG engine clean as vehicle was found to have contaminated oil" then reads, after this was done, the bad oil smell was gone. Prior to purchase, I did ask the previous owner what this was about, but no real definitive answer, but I did speak to the service people & they said it was to do with carbon build up & inferred the engine oil could have been changed sooner. (Oil & filter changed on that service record October 2015)

Anyway I have noted sometimes, it does still smell when down wind, I would say typically a smell associated with diesel engines. I've read things about the DPF (diesel particulate filter) as well when they're meant to self clean, but not too sure, so was wondering if this could be anything else or underlying item that I should investigate further.

I read an article by Auto Express back in the day when the Mk5 was released, it reads "the start up rattle & noise means the TDI isn't as refined as the petrol Golf" O.k. yes we all get that & having had a Mk4 Golf GT TDi 150 before this one, but would say the Mk5 does seem to have more diesel rattle at idle, however when on the move, say over 30mph, it's less evident & seems a quiet ride. Any takers on this one for more info ?

Over & out,
CJT53

More on the bad engine odour,

Reading further into the previous service record & from my garage chap who just fitted the new clutch kit. It seems the work the previous owner had done on the EGR (Exhaust Gas Recirculation valve) may be the problem. The service record says they tried to clean the EGR as caked with carbon. It also reads, they managed to free up the anti-shudder valve, but couldn't tell if it works as too much carbon build up in the EGR body inlet manifold.

They also did an engine re-map which included an EGR delete & a blanking plate in the EGR. My garage chap conveyed to me, if I understand him correctly, is that this may affect the DPF (diesel particulate filter) from working, hence the bad smell with the DPF not cycling & doing its job as a cleaning process. The engine also has a rough idle at tick-over, something my garage chap thinks are all related. Furthermore, when the Golf was up on the ramp with the u/s covers removed. I noticed some oil around the air duct intercooler pipe joint at lowest point. Anyway correct or not, I'd really like to get rid of this bad smell,... any takers on this one please.

Over & out,
CJT53

[Teflon]

Mr VW spent squillions engineering and optimising engines so that everything is hunky dorey.

Along come the folks who delete ERG valves, chop out DPFs or chip engines so that they will defeat the laws of physics and give an engine astronomical performance while at the same time using half the fuel. Some of them end up here, wondering what could possibly be wrong. Others, as in your case, pass the problem on to the next owner. I have some sympathy but to be honest not a lot, because buying a car with indications that the oil had once turned to tar really is asking for trouble.

Step one, put the car back the way it's supposed to be. If there are still problems, go forward from there.


.

[CJT53]

Mr VW spent squillions engineering and optimising engines so that everything is hunky dorey.

Along come the folks who delete ERG valves, chop out DPFs or chip engines so that they will defeat the laws of physics and give an engine astronomical performance while at the same time using half the fuel. Some of them end up here, wondering what could possibly be wrong. Others, as in your case, pass the problem on to the next owner. I have some sympathy but to be honest not a lot, because buying a car with indications that the oil had once turned to tar really is asking for trouble.

Step one, put the car back the way it's supposed to be. If there are still problems, go forward from there.


.

Hi Teflon,

I agree to a certain extent, however if the oil had turned that bad.... "TAR"..... it wouldn't be running as quiet & smooth as it does now. So more like a sales thing to persuade the previous owner to spend some cash on a re-map & EGR delete the car didn't need. Prior to this work, it had a full stamped service record & I also got an RAC inspection prior to purchase to aid my decision to buy or not, this was all positive.

"carbon build up & inferred the engine oil could have been changed sooner "


I'm contemplating the previous owners actions to reverse this, but at the same time think there may be some thought to leave it as is, even the BIG boy's in engineering design sometimes get things wrong, just because they have to meet emission controls.

Exhaust gas recirculation (EGR) is a system that takes exhaust gas from a diesel’s exhaust manifold & reintroduces it into the intake of the engine to reduce the combustion chamber temperature. The EGR is used to reduce the formation of NOx emissions, which are created when the combustion chamber temperature is high. The EGR directs the exhaust waste in part back into the engine to which cools the combustion chamber because EGR has almost no oxygen in it. Without oxygen, the temperature stays below the NOx-producing threshold & the emissions are cleaner. The EGR gasses from a diesel tend to be sooty, that soot gums up the EGR valve, EGR cooler, intake ports & any sensors that are exposed to it over time. So intentionally in part a reasonable design idea, but in practice short lived as all these things grind to a halt from the very thing they were meant to prevent in the first place. So your garage ends up being your chimney sweep on a regular basis, how much filtering is of course questionable between chimney sweeps...

As noted before, the oil around the intercooler pipe joint at lowest point I've since learned is a common fault at this low point on the pipe. I read it was oily gas from the injectors condensing, the pipe higher up was clean, if oily at this location, it could mean the injector seals were worn, but I also read the seals seal better a higher temperatures, so "town" or "Sunday"driving in modern diesels compared to motorway driving isn't a good thing if done routinely, I digress. Anyway I think the bad odour may in fact be some of this small amount of oil from the intercooler pipe finding it's way to a hot part of the engine casing & thus burning off to this noxious smell.

I'll report back when my garage chap has another look-see on this one.

Over & out,
CJT53

[Teflon]

Yes, I'm aware of the purpose of EGR and some of the potential issues. My point is simply that with modern engines there's so much interconnectedness of the systems that things are best left as designed and kept in that condition when they deteriorate.

Your concern about town driving is realistic, unless a diesel is getting regular long runs or gets an italian tune up there's more than enough potential for problems. As for the smell, don't get too hung up about it unless it's persistent. There can be a bit of a pong when the DPF is recycling, which I found especially noticable if it had just started a regen as I pulled up on the drive.


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[CJT53]

To all,

As promised, I'm reporting back from the previous posts on the bad engine odour/exhaust fumes after I asked my garage to do a specific inspection on this matter. They reported the following:-

"The fumes are coming from the turbo. The turbo is leaking through the wastegate arm and a small leak has been found through the banjo fixing to the DPF (diesel particulate filter).
We advise a new turbo to be fitted if you want to cure the sooty smell, other than that, there is no other fault found with the turbo".

Naturally I don't want to spend out on a new turbo, so I hope these are just everyday wear & tear items & if just left, will not cause any engine future problems. However can someone please confirm & is this a common thing on my Mk5 VW Golf 2.0 TDI DPF GT Sport (35k miles 57 plate). I guess I'll have to live with the engines fumes if there are no other fixes/parts that can be done rather than a new turbo !

Also not too sure about the comment on DPF.

Any advice will be most appreciated.

Over & out,
CJT53