JMSkoda94

Sorry for the late reply, works been busy and havent had chance to get on and update. Paulski - legend, ill look at that later on. So ive purposefully not used the blowers all week, and the coolant level has been fine. Yesterday on my way home from work, I had the blowers on. Checked level before leaving -OK. Checked level when got home (16 miles) - OK. Checked level when it was cold - Lost a little. Checked level before leaving for work this morning - lost a little more (now on the max line, as i overfilled last week). Checked when I got to work (16 miles) - empty. When waiting at a roundabout I heard a gurgling noise behind the dash. Proper head scratcher.

Hi Gaz, Thanks for replying. I dont think the heater matrix is leaking, ive put more than 5 litres in the expansion tank now due to the issue, and I would have thought the carpet would be wet through and smelling by now. I think what is happening, is that the heater matrix is blocked, raising the pressure of the system for it to then go past the 1.6 bar limit on the cap and blow out the top. As I know this is a common issue, which has been reported a few times before. However, like you say, I cant understand how turning the blowers on, links to an over pressure problem. Does anyone have a schematic of the cooling system with all lines, valves and components?

Morning all, Got a bit of a problem with my 16 Plate tdi VRS. Had a coolant loss issue for a while now, it wouldnt happen all the time, but sometimes when opening the bonnet I would find the coolant tank empty, or the fault would come up on the dash. Ive now confirmed that the coolant only ever empties, after ive had the blowers on inside the car. Hot or cold, it doesnt matter. I also found that it tends to come out of the expansion cap, so it seems to be over pressurising the system. Took it to my mechanic (before I found it was emptying when using the blowers) and he changed the expansion tank and cap. But it is still loosing coolant, but only when the blowers are turned on. Worth mentioning that when I turn the blowers to "HI" (hot), I dont think it gets as hot as it should, when the car is warm. If I dont use the blowers at all for days at a time, the coolant level will not change. Turned them on halfway home yesterday, and the coolant tank was empty. Also the temp gauge stays at 90 constantly once up to temperature. Am I right in saying this is a heater matrix problem? Thanks alot.

Absolutely! In regards to the potential piston ring issue. We can only advise. Though, have you removed the injectors and used a borescope to inspect the cylinder walls? If you have any scoring then it would look like a ring issue. This would give you a better indication of whats going on, and if they are scored, then youll not be wondering anymore. But then this may also be delaying the inevitable of starting the dreaded job. After reading and researching about the problem the past month or so, some seem to have gotten away with removing the pistons, cleaning and fitting new rings. But this would depend on a number of things, such as piston/cylinder wall condition etc. When i was worrying about it, I thought about buying a second hand CUPA/CUNA block, having that machined 0.5mm oversize to match the new pistons, then swap everything over. Saves having the car out of action for longer, waiting for your original block to be machined. You could then get your original block machined with new pistons and sell it on, try to recoup some of the money spent to sort the issue.

When mine was using as much as it was, there was no indication from the exhaust that it was burning oil, I couldn't see any blue smoke etc. How much oil is the car using? As above VW tend to say 1 litre in 1200 miles is "normal". However, in my personal opinion and experience in working in maintenance engineering for 15 years, its far from normal. Service covers, and bonnets should only be opened when there is a breakdown or service required, having to open the bonnet once a month to top off oil is far from ideal. Especially with the technology and tolerances we work to in this day and age. Might be worth putting some engine flush through, letting it circulate, then change oil and filter with the LiquiMoly 4200 and using the ceratec. If youre planning on a strip down and machine anyway, then theres no harm in spending 80 quid just see what happens.

Got my VRS back after using around 200ml in 100 miles. Gave the garage the benefit of the doubt, and they replaced the whole cam cover, which has the PCV valve integrated. I did do another 100 miles before checking the oil again, and even though it did go down a little, no where near as much as when I first bought the car. Linso, after doing my own research on these engines, there are a few things to check before opting straight for the engine change. Have you had any parts changed to rectify the issue? PCV valve, turbo (seals) etc? Ill be checking my oil periodically until my next service, then I will be changing oil to LiquiMoly 4200, and then checking again periodically, see if it has made any difference.

Target was probably the wrong word. What i meant was that when and if I get it back, and it falls into where VW themselves say is acceptable.

Goes without saying, these engines are finicky, to say the least. 500ml over 150 miles is alot, but to be honest 1 litre over 1200 miles is also a lot! If you're having to put 10 litres of oil in to your engine per year, based on average mileage in the UK, that is simply bad engineering. Ive given my car back to the garage to get the problems sorted, seeing as it is under warranty. Although, if they manage fix it to VW's 1 litre per 1200 mile target, then I will test the theory in my original post.

I imagine that the valve will open and close at different rates, depending on how you are driving the car. Open when giving it some beans, as the DPF will be getting plenty of flow anyway. And closed when sat in traffic etc.

Funnily enough, I asked the same question when my mechanic had my car up in the air last week. I thought it was a "valve tronic" type jobbie, so when you put your foot down it opens more, but apparently not. If its the same thing you're talking about, its a valve which opens/closes when doing a DPF regen. So it restricts the flow and increases pressure in the DPF, to make it run hotter, for a more effective regen. At least, that's what the mechanic told me, and how I interpreted it anyway. Others here may be able to elaborate, or tell me i'm wrong. 🤷‍♂️

I know people are probably getting bored of this topic, but Skoda's are new to me, I certainly didn't expect VW group of all manufacturers to have this sort of problem. Especially with an engineering defect like this. Anyway, I bought my 2016 Octavia VRS a couple of weeks ago, I saw it on the forecourt and immediately knew that I wanted it. Usually, I research common faults before buying cars, but thinking Skoda was a reliable manufacturer, I took the plunge. It was only after I bought the car I found out about the dreaded CUPA/CUNA oil consumption issue. And, I am in fact using more oil than id like. Around 1/4 of the dipstick gauge in 100 miles, so probably 1 litre of oil per 500 miles? I did come across a thread on here, which said that they used Liqui Moly engine flush, then filled with Ravenol SVMP 5w30 oil, with a Liqui Moly Cera-tec additive. As well as, just using a different oil, Liqui Moly 4200 5w30 oil. Can anyone confirm this actually works, from personal experience? Is it as simple as using a better quality oil, (or at least better option of oil for this particular engine), especially at the milage these cars are at now? Assuming all other components are in serviceable condition, DPF not blocked, EGR not clogged, turbo seals not blown etc. I have contacted the garage I bought the car from, but id like to know for future servicing reference, that is if I keep the car. Thanks all.

Hi, new here, but have been reading up on alot of topics in the forum since I bought my car. Many questions to ask in the coming weeks!