GeneralPurpose

After many years of being on this site I'm at this point of saying goodbye, permanently! A bit of a wrench although I haven't actually posted on here for a while now, it is still a wrench to finally go. Many of you won't remember me these days I'm sure. I was Estate Man for many years but had a name change later. After a string of really good Skodas I stopped buying Skoda cars after two brand new motors turned into disasters causing me to reject them. Dodgy engines and rubbish failing DSG gearboxes sealed the fate of Skoda with me I'm afraid. I moved to Citroen which I have to say I don't regret, but would have still come back into the fold if Skoda had offered something a bit better at that time. Anyway, I'm retired and spend inordinate amounts of money on motorcycles and scooters these days as I have my second childhood!! It's been really good on here and it's a great site. Thank you one and all, and I wish you all and the site the very best for the futures GeneralPurpose

And they do actually work which is nice!

Hi hetty1, Oil in unopened cans or bottles has a variable shelf life dependant upon the type of oil that it is. A general rule of thumb for synthetic oils is either 4 or 5 years (depending on the manufacturer and type of oil). Checking with the oil manufacturer will tell you exactly. Generally, the more additives in the oil the shorter the shelf life. The variability on those time scales is due again to what the exact type of oil it is. Once opened, oil even with the cap screwed on will last only 2 years at most, and that's pretty much all oil types. The reason oils like this have a limited shelf life is due to the additive in the oil breaking down. Some of the additive actually turn to water and can no longer do their job. Other additives just break down and don't work properly.

Personally, I'd walk from a car if it's got no provable service record. The engine will have suffered going so far without an oil change. As said above, water in the headlights is common. It's covered under warranty if the misting doesn't go away, but it won't be on yours I doubt.

VAG are already slowly abandoning DSG dry clutch boxes on their smaller to midrange cars in favour of fluid transmission boxes (torque converter style). These are lighter, tougher, smaller than DSG gearboxes and are less complex. They don't suffer problems either. They are cheaper to produce too. I recently drove the new Golf with the 8spd torque converter gearbox. It was lovely, smooth, precise, economical. No clutches to wear out. I suspect the Fabia will be getting something similar. Many manufacturers are already going down, or will be going down the torque converter path instead of DSG and CVT to reduce transmission issues.

Even mapped Danny, yours will be fine if she's running sweet. We mapped several test engines as part of our development work with no adverse effects. Many of the engines running GPF's had been running for over 3 years without GPF issues. As you very rightly say above, petrol and diesel filtration systems work differently, under different conditions and cannot in reality be compared. Although that is what several folk are mistakenly doing here. It is however understandable that they are doing this because the technical side of the GPF is still not clear to people, or the different conditions DPF's work under compared to the GPF. During my last contract earlier in the year, the engines we were developing concentrated on killing the particulates in the cylinder, AND in the GPF. So little debris was created there wasn't much for the GPF to actually do. To be clear, it was the engines I was primarily testing and developing, not the GPF's. A consequence of this meant intense monitoring of the GPF's, cutting them open to ultimately check the contents. Nothing was left to chance, measurement has to be precise. OBD is good but not as accurate as needed for our work. This data was collected and used in my overall work of developing our engine control systems ie: software, induction and exhaust, cylinder head design etc. We had people developing GPF design but that isn't what I did. Having seen what I've seen, I'd be very surprised to see issues with GPF's. Regarding what George posted to reference Ford GPF issues, and I'm speculating based upon third party knowledge from other engineers I spoken to. The main issue I believe is the engines and their control systems, NOT the GPF's. I'd remind everyone the eco boost engines have in the past had a very bad reputation from a number of angles. They make the twin charger VAG group debacle look comparatively mild and has cost Ford a small fortune to try to put right. It is finally becoming a better engine but not sure it's quite there yet.

Your understanding is pretty good John. There is no regen on a GPF in the same way as there is on a DPF. It isn't required. But when/if a partial blockage occurs the procedure above should be implemented. During the procedure some tiny amount of ash does get ejected, but mostly all that happens is the debris gets a good shake up which unclogs the filter, allowing the ash (which is mostly harmless) to settle in a collection chamber. It will take a car lifetime to fill this area for most people. My own car is 15 months old and has covered 31,000 miles. I did most of that mileage whilst working on my last engine development project before retirement. It is a turbo petrol car with a GPF. The last 8k miles has been town and urban work, stop start from cold etc. No issues with GPF. In my garage I have two GPF's that I cut open ready for examination while on the engine project (didn't need them in the end). Both over 2.5 years old, both with in excess of 75k on them. Neither of them has any real amount of debris in them. Both good for another 75k. GPF's are not a new concept, there won't be any settling in of the technology. It's been about for years in some quarters. Although they may seem similar, DPF's & GPF's are not the same thing and should not be compared. Yes they both filter exhaust gases but as said earlier, DPF'S have a very different life and work differently.

Thanks Danny. Wino, no confusion here. But sorry I haven't explained it well enough for you to understand.

GPF's and DPF's both emit small amounts of ash during use, but GPF's are very different and are capable of emitting much more ash should anyone ever be unfortunate enough (unlikely) to get a clog. GPF'S generally don't get all sticky inside under normal use. If you notice the VAG instructions for removing the clogged particulate matter is to use high revs and then come off the gas for long periods, just letting the vehicle slow under it's own steam. This creates a vacuum in the GPF sucking matter up away for the honeycomb and making it airborne. Pressing the accelerater again and rapidly increasing revs expels the dirt and any burnt up ash. It can remove quite large amounts Normal driving will do this to some extend too.

Not quite sure where you are going or what you are trying to say. I've already explained there isn't a direct comparison between what a GPF and DPF have to cope with. A GPF isn't going to collect massive amounts of ash even if the engine burns just a bit of oil as most engines actually do. Most particulate matter is vaporised to a gas and leaves no ash. They are designed to cope with the amounts of oil use that manufacturers say is ok for their engines to burn. For most it's up to 1litre of oil per 1000 miles (quite a high oil burn rate), some allow more oil use. The GPF's cope ok with that and it won't affect their normal lifespan. Remember, not all ash is kept in the GPF or a DPF. Ash gets expelled during regens and in the case of a GPF the same happens. You can do the GPF clearance exercise to remove ash if you want at anytime. It doesn't rely on a regen cycle like a DPF does. But so far over the years of dealing with GPF's, I've never ever seen one with any real amount of ash in it. Some of our test cars had covered over 90,000 miles with a GPF fitted and been driven for over 2.5 yrs in every sort of environment and put to every type of use in every type of traffic. I've worked on vehicles of many types with GPF's for over 12 years and none of them had any issues. Under normal use a GPF will last the life of the car like your CAT does. If a diesel engine is burning a lot of oil it will make a lot of ash and both it's CAT and DPF will eventually be affected. It will obviously follow that it will be the same for a GPF if the engine is burning a lot of oil. BUT, with a GPF, you'd have to burn a huge amount of oil to get issues and in that case you are far more likely to be worried about buying another car that isn't clapped out than the GPF.

I've never disagreed Wino if you re-read my posts above. On the subject of so many words, just trying to give reassurance and understanding which many on here don't seem to have. it's clear many folks are making a link between DPF's and GPF's. That's understandable. But folks need to be clear that the life of a DPF is vastly different to that of a GPF. A DPF has to stop particulate matter produced by an engine that burns entirely a dirty fuel oil product. This makes a lot of soot and other particulate matter all the time the engine is running, and that's made worse by the fact diesel engines have a considerably higher compression ratio than a petrol engine (producing more particulates) with the exhaust gases running very much cooler at the DPF unless reheated. All this means even more particulates will have to be trapped by the DPF. Therefore a DPF has a considerably bigger job to do on a diesel engine which results in very much more ash than a GPF has to deal with on a petrol engine. There is no comparison between the volumes of matter a petrol engine produces and that of a diesel engine.

Wino, I've worked with teams who design these things and I've tested them over the years. I tested the first GPF's way back in the early noughties. These were for specialist engines. Surprisingly, GPF's haven't changed too much regarding their innards, but the thing that has changed is the engines they put them on and the oils and fuels that burn through them. Also they are monitored with better electronics. Firstly, the fuels we burn are better, cleaner and make less pollution so that's a help to the GPF. Secondly, engines themselves run cleaner with massively less pollutants than ever. Thirdly, modern oils used in engines produce much less ash when burned, if indeed an engine is using some oil. Don't forget that the idea of the GPF is to incinerate the particulate matter to almost nothing at a very very high temperature. So high in fact that the particulates are vaporised to a gas, not ash. Inevitably, some tiny amount of matter will remain as ash but the quantity of ash per volume of matter incinerated is very very low. Very little remains in the GPF per 1000 miles covered by an average driver. In fact, when we split them open to observe how much matter was present, often it was not easy to see anything at all. But if someone is driving a car with a thirst for oil then obviously there will be more matter present. We tested many engine types but found no issues with ash content because in essence there was no or very little matter present inside a GPF even after very high mileages. So they work fine in normal service. They are not as touchy as DPF's and don't have to deal with anywhere near the amount of debris that comes from even modern diesel engines. In addition the GPF's have a tolerance built in to ensure that properly running and serviced engines will not cause the GPF any issues, even if an amount of oil is burned. However, if the engine is using excessive amounts of oil it will impact on both the CAT and the GPF eventually. This is what anyone would expect. The average GPF will last the life of the car, just like a CAT will.

puny, yes indeed they do.

Hi George, the 'we' is me and the firm I worked for in my last few months before retiring. GPF's are quite honestly very reliable. I've never yet seen or heard of anyone with a problematic GPF and although they are now being fitted universally to nearly all modern cars, including many port injected engines, they are not new. Of course this doesn't mean someone could not get an issue, but you'd have to use the car for very short trips over and over and over again without the engine ever warming up, ever, before you get a problem. By then you'd have other issues with plugs fouling, too much fuel and water in the oil etc etc. So VAG is covering itself by giving the right advice to anyone that gets a clogging issue. But you'd also need to look at how you are using your car too and maybe consider a push bike with a basket instead. 😀

Hi Wino, funnily enough we didn't find any problems with GPF's on engines that burned oil. And, it's the same for CATS. Because CATS and GPF's are mounted so close to the cylinder head exhaust manifold, or if there is no exhaust manifold as on my car, and just the exhaust outlets from the cylinder head, burning a bit of oil makes no difference. Both the CAT and the GPF burn at incredibly high temperatures and are combined units in most cases, so it's difficult for ash in any quantity to form in petrol engine GPF units even if they burn a bit of oil. They certainly are not affected by any car burning 1litre of oil in 1000 miles or even much higher amounts. The gas pressure too is intense within these combined units which along with the high incineration temps keeps the GPF and the CAT pretty much completely clear, reducing particulate matter to a fraction of its original size. In fact we never found any noteworthy amount of ash in any GPF/CAT combined unit that had covered 100,000 miles or more. Clearly, if a particular car is burning larger amounts of oil than the figure I mention above then it may affect it sooner. The message is, GPF's don't cause any issues. just like CAT's really. When was the last time you replaced a CAT due to large ash formation?