Hyundai cars with a DPF usually have a notice on top of the engine warning you it has a DPF and you must use synthetic engine oil class ACEA C2 or C3
The info should be in the car manual.
Yes, I know about the sticker. And mine has one saying its not fitted with a DPF. But the car's symptoms made me consider that maybe it had been mislabelled, and that it may in fact have a DPF. I can't otherwise figure out how I could end up with twice the volume of oil in my sump than there should be - black cooked "carbonised" oil. Plus I've got caked black soot at the tailpipe which previously was always totally clean. I also have major starting issues - somewhat variable making diagnostics difficult - from delayed firing with white smoke, to cranking no start requiring towing. The latter seemingly after longer drives and cold conditions. Not that its been driven much in the last six weeks. Its been with registered repairer, then went to injector specialist (all injectors good), and now returned to me as noone knows what to do with it.
Anyway with my car home I had the opportunity to check it over and checked the oil almost for old times' sake. I was dumbfounded by what I found - the oil came up to twice the distance from the full notch, and instead of clean, clear oil as I normally see - it was black.
In desperation I read everything I could to understand if there was any way fuel could get in there (not oil by massive slip of hand of the mechanic surely, nor water as no entry route). I stumbled on to DPF's and learned about how when they get too much particulate in them, the ECU instigates self cleaning by injecting fuel to increase temperature in the exhaust and burn off the carbon. I began to wonder if the sticker was wrong and so I got a torch and took a look.
If indeed I have a DPF, I can tell you there is a strong reason it could be pretty darn clogged at this point. All this started back on 21 April when I got a batch of bad diesel - watery, biologically contaminated diesel. I noticed loss of power and loud idle. Seven days later when registered repairer got to it, they found a thick layer of brown sludge in my fuel tank. It had clogged the fuel filter and they said it had gotten through to the injectors. I can only think that cooked dead microbes and bioslime have gone on to contaminate the exhaust system amd overwhelmed the DPF (if I have one) with all that bbq. I'm concerned for the catalytic converter also, but the cat doesn't push extra fuel into the engine sump. Only a DPF would do that.
This car was car of the year in 2012, and it was the greenest, cleanest diesel in Australia with Euro 4 (non DPF) emission standard. I remember being incredibly impressed with the absence of soot and diesel smell from the exhaust, and no one picked it as a diesel. I wouldn't be surprised if mine was mislabelled as not having a DPF when in fact it does. Maybe a few got through mislabelled which I might explain a few other posts on here.
One other thing - no warning lights came on throughout all of this, and no error codes have ever come up for the mechanics. No the ECU is not faulty, despite glitches with nearly every computer update that 'don't take'. This car's brain is working, it just has a mind of its own.
As for the manual - yes it specifies different oil based on whether you have a DPF or not. Hopefully one day before the car get's carted off to the wreckers I'll find out!