2nd gen 3.0 TDI ALL Issues

The 2^nd generation 3.0 TDI engine marks the beginning of an end. An end for a powerful, economical but still relatively durable diesel engine which can easily last more than 500 000 km.

Would I buy it?

No. Because I hate the big amount of various plastic parts in this engine and the additional complexity. To top of that, cars with the 1^st gen 3.0 TDI are still widely available to buy – so I would choose one of those. However if I would have to buy a used car out of warranty equipped with the 2^nd gen 3.0 TDI engine, then I wouldn’t be afraid to buy it (even though I would swear a lot during replacing those fucking cheap plastic parts).

On the other side, what I’m a bit afraid of is the 3^rd gen 3.0 TDI – which is essentially just a newer/updated version of the 2^nd gen engine. This maybe doesn’t sound that scary, but the potential issues it can have are definitely scary enough!

The most noticeable visual difference between the 2 engines is, that the crankshaft pulley in the 3^rd generation has only 1 bolt + the intake manifold looks a bit different as well.

2nd gen 3.0 TDI

The main construction of the 2^nd generation 3.0 l TDI is similar to the 1^st gen. This is still a V6 common rail diesel engine with a cast iron engine block, aluminum cylinder heads and 1 electronically controlled turbo on the top. However numerous things are updated on it like the:  

• simpler variable intake manifold with only 2 main flaps
• redesigned/simpler timing chain mechanism
• updated EGR system
• updated more complex cooling system
• updated oil pump with integrated vacuum pump
• new oil filter housing, new valve covers, new front engine cover and some other details

On the other side I have to add that this is essentially not a bad engine, because with proper regular maintenance it can last more than 500 000 km. But since it’s a more complex newer generation diesel engine, you have to expect some more and less expensive issues and a big amount of annoying oil + coolant leaks.

You can find this engine in many different cars ranging from a ^4th generation Audi A4 thru an A8 D4, to the 2^ndgeneration VW Touareg or Porsche Cayenne. Or even in a first generation Porsche Panamera. Some of these cars like the A6 (C7) or the A7 (C7) for example can be equipped with also the 3^rd generation 3.0 TDI. 

Issues

Injectors

The injectors themselves can get faulty usually just after approx. 200 000 km and the injector washers can start to leak – even after 100 000 km, but I will come back to these topics at the end of the article.

Injector bolts

Another issue related to the injectors are the injector bolts – which can simply get loose or even break. In this case the injector will pop out which you will definitely notice because of the various symptoms like: rattling/ticking noises from the engine, check engine light, limp mode, cylinder misfire-uneven engine running.

High pressure fuel pump

The HPFP in these engines is a Bosch CP4 pump, which will mechanically fail at some point – releasing tiny metal particles which will destroy all the injectors. Nobody knows when exactly it fails, since it can rarely fail before 200 000 km, but usually just after this mileage point or just after 400 000 km. However, this issue is not extremely common and it happens usually just in the eastern part of Europe and in the US because of the different quality of the fuel. The HPFP is located on the back of the engine under the intake manifold and basically almost under the turbocharger, so replacing it is absolutely not that easy like in the 1^st generation 3.0 TDI engines.

Using good quality fuel eventually good fuel additives will prolong the lifetime of this pump.

Turbo

The turbocharger mounted on top of the engine will fail at some point together with the electronic actuator, but mostly just in higher mileage cars – after approx. 300 000 km.

Crank pulley

The crankshaft pulley at the front will fall apart sooner or later – causing the accessory belt to jump off the same way as on the older 3.0 TDI engines. So if the pulley looks worn or rusty, then it’s better to replace it preventively!

Oil / coolant leaks

Next there are the leaks. And let me tell you, this engine was literally made to leak oil and coolant ! The various leaks which will mostly magically appear between the cylinder heads are actually really famous, so let’s start with the list:

The oil can start to leak from:

• valve cover gaskets and valve covers themselves
• gaskets of the oil cooler and the gaskets of the oil cooler base plate located between the cylinder heads
• oil thermostat o-ring
• seals of the oil filter housing + the oil filter housing itself
• rear main seal
• + the various covers like the timing chain covers at the back or the front crankshaft cover which are sealed with sealant from the factory are gonna eventually slowly leak oil

The coolant can start to leak from:

• oil cooler
• a small plastic coolant flange behind the oil cooler
• a plastic coolant regulating valve behind the coolant flange
• a plastic coolant cover which is mounted onto the main front engine cover/in front of the oil cooler. The only way to remove this small plastic coolant cover is to remove the whole big metallic front cover of the engine which is not an easy nor a quick job + during this you will have to replace the gasket of this big front engine cover as well. (this is clearly a shit design since the previous gen of this engine has this part made entirely from metal)
• oil filter housing which also contains the main thermostat
• plastic coolant pipe on top of the engine which is located in front of the turbocharger

Long story short, all the gaskets and o-rings between the cylinder heads are gonna leak sooner or later and all the plastic parts are gonna eventually crack and leak. So when you get a leak between the cylinder heads you got 2 options basically:

1. you either replace the gaskets and the plastic parts one by one, or in groups and wait for the other stuff to fail and leak

2. you simply replace all the possible gaskets and parts which can leak at the same time, or at least all those which are not easily accessible – and have a piece of mind for a long time

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Timing chain

Unlike the first generation 3.0 TDI, this newer 2nd gen engine is equipped with a redesigned/simpler timing chain mechanism. Despite the fact that it’s redesigned and simpler, it can still get worn and sometimes even prematurely. Mainly in cars made to 2013 the chain can start to rattle before 200 000 km and sometimes even before 100 000 km – in many cases because of the early weaker chain tensioner. Cars made from the end of 2013 should have an updated chain tensioner fitted, so in these newer models the chain should not start to rattle that early.

Interestingly, plenty of people and even mechanics are gonna tell you that a short rattle in these engines after start up is fine. Well, there is a bit of truth in this. The chain failures on these engines causing catastrophic damage are not very common, so it is perfectly possible that even with a short chain rattle at start up the chain mechanism lasts more than 300 000 km. However I have to add that if you hear a chain rattle at start up, then there is a chance that the chain jumps and causes engine damage-mainly if it’s too loose. The problem is, that you simply don’t know how loose the chain is without inspecting it directly. So a chain rattle is definitely not a normal condition.

At around 300 000 km it’s a good idea to replace the chain mechanism preventively even if it’s not rattling, because the tensioners and the plastic guides are gonna be worn to some extent, the plastic guides can even break + on high mileage cars the chains will stretch as well.

Other stuff

1. Various sensor/switch failures can occur

2. Issues with the EGR valve or with the throttle body actuator can occur

3. Vacuum solenoid

The vacuum solenoid on top of the engine can fail. And this is interesting, since in this case you can usually experience that the coolant wont reach operating temperature/or fluctuating coolant temperature… and a P199E fault code stored is also a symptom of this faulty valve (P199E coolant valve for cylinder head – fault code)

4. Dieselgate software

Keep in mind, that cars which have the dieselgate software update can experience various issues like: bigger fuel consumption, a bit more rough engine running, slight loss of power, more DPF regen. cycles-noticeable oil dilution with fuel. That’s why it’s always a good idea to downgrade the software to the older original non-dieselgate version.

5. Variable oil pump

The newer engines made from 2009 have a variable oil pump with 2 pressure stages regulated by a pressure regulating valve. This valve is located on the front lower part of the engine so it’s easy to see and access it. It can sometimes fail so it’s a good idea to replace this valve preventively after 200 000 km because it’s not that expensive.

This valve plays an essencial role in oil pressure regulating, so forget about the aftermarket replacements !! Buy only a genuine oil pressure regulating valve !

on the next page: injectors, DPF, mysterious coolant loss