Bloke on service reception at Volvo main dealers tells me that the UK is the only country that has problems with EGR valves choking up and it's because our air is so humid that and the soot particles stick to it and hence the valve. Is he pulling my leg?
EGR valves
- Thread starter DaveHerns
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Never heard of that one, I just put it down to the fact that we are always bloody cold over here and do many cold starts. Certainly the EGRs that I take out of short run diesels have to be seen to be believed!
I'm running all of mine on advanced diesel fuel out of curiosity to see if it makes any real difference.
John
I'm running all of mine on advanced diesel fuel out of curiosity to see if it makes any real difference.
John
I think he was giving me BS ! My V70 is going in for a " EGR rework kit" I get the impression Volvo are struggling to get their emissions down without coking up the EGR valve and cooler but they're trying to keep a lid on the problem.
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It sounds like absolute nonsense. Isn't the EGR fed entirely by exhaust gases ? Any small difference in UK ambient humidity from any other country will certainly be destroyed by passing through the combustion-chamber .
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Whatever is said about the EGR system, they do work in the way they are supposed to so we are stuck with them......I haven't come across one fitted to a turbo petrol engine so far so can't comment there.
I've had them totally filled with grot and can't really understand why. Example - Skoda 1.9 PD, short runs only, 4k per year max, so much clag in there you couldn't pass a finger through. Another, Skoda 1.4 common rail doing 50k per year. Just the same!
John
I've had them totally filled with grot and can't really understand why. Example - Skoda 1.9 PD, short runs only, 4k per year max, so much clag in there you couldn't pass a finger through. Another, Skoda 1.4 common rail doing 50k per year. Just the same!
John
Maybe it depends on how "clean" the engine burns? I never had any problems on Euro 4 or 5 diesels. Are these fuel additives or aerosols you spray down the air intake any good or are we stuck with removing the valves and cleaning/renewing at regular intervals? Mine has an EGR cooler so maybe it's cooling too much?
I guess these are the questions that everyone would like the answer to!
Considering the volume of crap that I have scraped out of an EGR you would need a gallon of cleaner to get anywhere, and I've found the VAG PD engine one of the worst for fouling......so much so, the valve couldn't actually open. That one was on an 07 car, 70k. Non turbo diesels fare reasonably well (PSA) but maybe they don't do as much work - I really don't know.
Usually I'm able to clean them but have been defeated twice.....both 1.4 common rail units, one Ford, one Skoda.
In due course I'll see if the V Power diesel makes any difference and I'm testing this on a Nissan 1.5dci, a Peugeot Bipper I think that's a Fiat lump but I don't recognise it, and a 2.0 VAG. All vehicles are doing around 10k per year, and very few short runs.
John
Considering the volume of crap that I have scraped out of an EGR you would need a gallon of cleaner to get anywhere, and I've found the VAG PD engine one of the worst for fouling......so much so, the valve couldn't actually open. That one was on an 07 car, 70k. Non turbo diesels fare reasonably well (PSA) but maybe they don't do as much work - I really don't know.
Usually I'm able to clean them but have been defeated twice.....both 1.4 common rail units, one Ford, one Skoda.
In due course I'll see if the V Power diesel makes any difference and I'm testing this on a Nissan 1.5dci, a Peugeot Bipper I think that's a Fiat lump but I don't recognise it, and a 2.0 VAG. All vehicles are doing around 10k per year, and very few short runs.
John
To the OP, no, you were being fed waffle, I'm afraid. As others have said, it gets exhaust gas, so any moisture would be long gone within seconds of firing up! I think the fouling in the UK is more to do with our heavy traffic and low combustion temperatures. Mrs. Avocet runs a nissan X-Trail T30 diesel with EGR. There are plenty of tales on their forum about blocked EGR valves (and indeed, entire inlet manifolds)! Some of the photos need to be seen to be believed - barely a hole big enough to poke a pencil into, on some of the inlet manifold runners! As there is so much trouble with them, I decide to take Mrs. Avocet's EGR valve apart to clean it at about 90,000 miles while I was doing another job nearby. To my surprise, it was as clean as a whistle! I could rub my finger around the inside of the pipe and come up with a fine layer of dry, dark grey soot. I had occasion to do similar at about 115,000 miles with the same result. That got me thinking...
...we've never had fantastic fuel economy out of the car. 32-3 MPG typically on most tankfulls. That's partly because I "drive it like I stole it" once a month - AKA the "Italian tuneup". It's also because Cumbria is hilly. (Incidentally, we live near the wettest place in England, so I think that helps scotch the theory about damp air)! I wondered whether there was any correlation between the people who got nearly 40 to the gallon out of their X-Trails, with the people who also got sooted-up EGR valves. Unfortunately, the numbers were too small to be statistically significant, but I think I WAS beginning to see a bit of a correlation. This is further borne out by my dad's experience (self-employed mechanic now in his late 70s but refusing to retire)! In his experience, it's the taxis that never do airport runs and the "old dears" who have dust on their rev counters above 2000 revs who tend to suffer from accumulations of oily soot.
All this leads me to conclude that provided you get the exhaust gas temperature high enough once a month or more, you probably won't suffer the problem - but in order to do so on a diesel without a DPF (and thus without all the smart-arsed technology to make it run stinking hot once in a while), you need to get the combustion temperature up by driving at maximum power (i.e. wide open throttle and at whatever RPM the engine develops max. power) for a bit every now and then. With me, that's easy. There are lots of steep hills here and I have a big trailer. For others, it might not be so easy (without losing one's licence)! About 4500 RPM on a wide open throttle once a month for about 30 seconds or so is plenty for the X-Trail. More modern diesels might develop max power a bit higher in the rev range.
Lastly, if all else fails, the guys on the X-Trail forum seem to be impressed with the "Terraclean" process.
...we've never had fantastic fuel economy out of the car. 32-3 MPG typically on most tankfulls. That's partly because I "drive it like I stole it" once a month - AKA the "Italian tuneup". It's also because Cumbria is hilly. (Incidentally, we live near the wettest place in England, so I think that helps scotch the theory about damp air)! I wondered whether there was any correlation between the people who got nearly 40 to the gallon out of their X-Trails, with the people who also got sooted-up EGR valves. Unfortunately, the numbers were too small to be statistically significant, but I think I WAS beginning to see a bit of a correlation. This is further borne out by my dad's experience (self-employed mechanic now in his late 70s but refusing to retire)! In his experience, it's the taxis that never do airport runs and the "old dears" who have dust on their rev counters above 2000 revs who tend to suffer from accumulations of oily soot.
All this leads me to conclude that provided you get the exhaust gas temperature high enough once a month or more, you probably won't suffer the problem - but in order to do so on a diesel without a DPF (and thus without all the smart-arsed technology to make it run stinking hot once in a while), you need to get the combustion temperature up by driving at maximum power (i.e. wide open throttle and at whatever RPM the engine develops max. power) for a bit every now and then. With me, that's easy. There are lots of steep hills here and I have a big trailer. For others, it might not be so easy (without losing one's licence)! About 4500 RPM on a wide open throttle once a month for about 30 seconds or so is plenty for the X-Trail. More modern diesels might develop max power a bit higher in the rev range.
Lastly, if all else fails, the guys on the X-Trail forum seem to be impressed with the "Terraclean" process.
I guess these are the questions that everyone would like the answer to!
Considering the volume of crap that I have scraped out of an EGR you would need a gallon of cleaner to get anywhere, and I've found the VAG PD engine one of the worst for fouling......so much so, the valve couldn't actually open. That one was on an 07 car, 70k. Non turbo diesels fare reasonably well (PSA) but maybe they don't do as much work - I really don't know.
Usually I'm able to clean them but have been defeated twice.....both 1.4 common rail units, one Ford, one Skoda.
In due course I'll see if the V Power diesel makes any difference and I'm testing this on a Nissan 1.5dci, a Peugeot Bipper I think that's a Fiat lump but I don't recognise it, and a 2.0 VAG. All vehicles are doing around 10k per year, and very few short runs.
John
Yes it is. Bipper is a Fiat Qubo (and a Citroen Nemo).
I was reading that inlet valves and manifolds get coked up these days because of direct injection. With injection into the manifold, the valves were being "washed" by a fuel/air mixture and that kept them clean. Now they get fed a mixture of air and dirty exhaust gases. On that basis I cannot see fuel additives cleaning the inlet tract. The dealer did say to me to give it a thrash every so often but when you give a diesel full throttle it creates smoke/soot ( as seen behind many VW diesels). What I'm trying to say is that I would have thought thrashing a diesel would cause it to soot up?
Edd China advertises Terraclean, I'll say no more.
Edd China advertises Terraclean, I'll say no more.
Ours smokes for a bit when I do it, but if i do it a second time, it smokes much less. A third time and it doesn't smoke (at least, not so much that I can see it in the mirror). I think that's the muck being blown out.
For sure, the VW P.D engine was a bit of a smoker - probably the reason they are common rail now.
On a good blast, there is sure to be oil cleared from the intercooler and pipes - notice how grubby they get - presumably from oil misting from the turbo.
I've yet to experience the Terraclean process, but I guess its just a pure fuel injected into the exhaust upstream of the cat.
Did Redex ever work? Upper cylinder lubricant - I ask you!
John
On a good blast, there is sure to be oil cleared from the intercooler and pipes - notice how grubby they get - presumably from oil misting from the turbo.
I've yet to experience the Terraclean process, but I guess its just a pure fuel injected into the exhaust upstream of the cat.
Did Redex ever work?
Upper cylinder lubricant - I ask you!John
Did Redex ever work?
Well, after a double strength dose of Redex Diesel Treatment and a run on the motorway, my engine check light has gone out. Code recorded is for low EGR flow.
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