The early belt driven (BPY) engine which was used through mid 2008 (depending on model) is a pretty good engine, so long as it stays full of oil. They LOVE to eat oil. They can consume 5+ liters between services. They also had an issue with the cam follower for the HPFP wearing through. There is a TSB about this, as there is on some engines improves camshafts and followers, however the TSB also once again stresses the correct oil. Given the fact that so many of these engines burn so much oil, I tend to think that a lot of the cam follower issue is due to so many of them running around perpetually low on oil.
They also had some problems with the fuel pressure sensors, and some other minor control side hiccups, mostly fixed with software. Sooner or later, the oil consumption also causes catalyst failure. The BW turbochargers also get wastegate hardware slop, which can cause low boost DTCs even though the car never "feels" sluggish.
The late engines (CCTA, etc.) have all kinds of more intense problems. Many of which were addressed as that engine (which is still in production) has undergone lots of improvements. However, even the early versions had so many timing chain, timing chain tensioner, etc. problems that the replacement long block part numbers have about a half dozen supercessions between 2008 and 2012. By 2012 they have the newer style stuff from the factory.
But they still have the chronic crankcase breather valve sticking, causing the intake manifold and crankcase to be linked together, so when the turbo starts boosting, it also boosts the crankcase, and blows the seals out... most commonly the rear main seal, which is a REALLY dumbass design. Just a little round flap glued to a steel plate, and it just blows it right apart. I have probably done a hundred of these things. Not so bad on a FWD GTI, but much more labor intensive on an AWD car, especially something like the Audi A4 w/ automatic. I think that breather should be proactively changed every 20-40k miles. And the aftermarket ones are junk, even worse than the original (Hengst) ones, and I did not even think that was possible.
The other chronic issue the late ones have is the water pump. More specifically, the housing. They crack. And they start spewing coolant out the front (side) of the engine in a hurry. The water pump is this overcomplex thing buried underneath the intake manifold, driven by a tiny little toothed belt off the back end of the balance shaft (the balance shafts themselves are driven by one of the three chains in the front of the engine).
Of course, the intakes get to come off of these all the time anyways. If it isn't for the failed intake runner sensor (part of the intake, and part of a warranty extension on many models), then it is to scrape the crud out of the intake ports. Something that is common for all GDI engines, but for whatever reason these are, by far, the very worst of any of them. The BPYs did not seem to have nearly the trouble that the CCTA+ does. Short trips, cold weather, lots of idling, easy driving, wrong oil, etc. all make it worse. They'll manifest this as stumbles and misfires after a cold start, and poor uneven power delivery all the time. They can get to a point where they are almost undriveable when cold, especially with a manual, as they just run so terribly. And when you take the intake off, and look in the ports, they won't *look* that bad, until you start scraping on them. And even then, you would not think it could cause them to run so bad, that there must be something else wrong... but you get them all cleaned up and back together, and they run great again.
They also have the turbo wastegate linkage problem, but for whatever reason it seems even worse on these than on the BPY.
These engines, when bolted to manuals, use a DMF type clutch, and that flywheel is prone to failure. Luk, Sachs, whatever, they are all prone to failure. The DSG automatics also have this problem. The Aisin automatic (which the GTIs do not use) just eat a valve body every 80-120k miles.
When they are all dialed in, the do run great. Lots of power, lots of torque, and the delivery is flat and ample through the entire RPM range. And while they are no diesel, they will deliver reasonably good fuel economy at steady legal highway speeds, even if it does require premium gasoline.
I loathe the Tiguans because of these engines.... but I could stomach one if it was in a GTI with 3 pedals. Or maybe an Audi A3 (again, 3 pedals... life is too short not to shift your own gears).
All of these engines have ignition coil failures commonly. Luckily they are cheap and easy to replace.
The later versions (again, this depends on the model) have some extra improvements, and some stuff that just changed for unknown reasons (the oil cap? Seriously Volkswagen? After all these DECADES you had to change the OIL CAP so my fill funnel no longer works???
). The Audis got some of these changes first. And the latest change just happened for the 2018 model year, the Budack version.
I have owned a few GTIs over the years, I think my favorite is still the '86 I had. But I could enjoy a new one.
Blanket statement warning for purchasing ANY used GTI: these cars are often gluttons for punishment. They often get purchased new by people who really run them hard, beat on them at every chance, and neglect them... then trade them in before the real cost of this abuse is realized. So I would really try and find one that you have some ability to gain knowledge of its previous life. If it is some 20-something punk snowflake whose daddy bought him a new GTI for his birthday and smells like recreational drugs inside and has two original tires with 50% tread and two bald Chinapops, then chances are it has not been treated well. But if you are buying one from some 60 year old empty-nester who wanted to relive some of his youth before he moves to Florida to await death, and the car looks and smells like new and has been parked in his garage next to his wife's Buick Lucerne most of the time, it has probably been treated pretty good.
