You know, some problems give you a little warning before things go wrong. But others are different. The red oil pressure warning light comes on, and just a few kilometres later, your engine can be beyond repair. You end up needing another engine. Today, I want to tell you about one of those problems: 2.0 TDI oil pump failure on engines with a balance shaft module. And why I'm asking you, as a friend, not to wait for that warning light.
Which 2.0 TDI engines are affected by oil pump failure?
We're talking about 2.0 TDI engines with a balance shaft module that also houses the oil pump. We see this most often on the Audi A4 and A5 B8, A6 C6 and C7, and the Q5 with the 2.0 TDI engine. Engine codes include CAGA, CAGB and CAHA. Some older VW 2.0 TDI engines use a similar design too. Not sure whether yours is one of them? Give us your VIN and we'll check. There's no point guessing.
What exactly wears out in the oil pump?
The balance shafts drive the oil pump through a short hexagonal shaft. The trouble starts where that hex shaft fits into the gear. There's very little contact area, and vibrations from the balance shafts gradually wear away its edges. At first, the pump still turns, but it's no longer working quite as it should. The oil pressure starts to drop, even though there's still enough to keep the engine running. Over time, the hex shaft becomes rounded and starts slipping inside the gear. Then, one day, the pump simply stops.
If the red oil pressure warning light comes on, stop immediately and switch off the engine. Don't try to drive to the workshop, even if it's just around the corner. Without oil pressure, the engine bearings can suffer serious damage within minutes.
Why is this problem so dangerous?
Because you might not notice anything wrong until the very last moment. The car drives normally, doesn't burn oil and doesn't smoke. There's nothing to make you worry. Then, suddenly, the red warning light comes on. But that light only comes on when the oil pressure has already fallen below the critical level. That's why I wouldn't wait for any symptoms on these engines. I'd much rather we check things in good time than have to find you another engine afterwards.
How do we check the oil pump before it's too late?
- First, we check your engine code to see whether your engine is one of those affected.
- We remove the sump and inspect the hex shaft and the gear it fits into for wear.
- If we find wear, we replace the hex shaft with an improved version or replace the entire module. It depends on the condition of the parts.
- We fill the engine with the correct oil and measure the oil pressure to make sure everything is working properly.
Believe me, this is nothing compared with the repair bill you'll face if your engine loses oil pressure. Especially if your car has already covered 120,000–150,000 km and nobody has ever checked that hex shaft. If it were my car, I wouldn't put it off.
Does the engine oil you use make a difference?
Absolutely. Using the correct engine oil and changing it every 10,000 km or once a year, whichever comes first, won't completely prevent the hex shaft from wearing out, but it can slow the wear down. That's the interval I recommend for cars driven in Bulgaria, regardless of which engine oil you use. If you keep driving with old, dirty oil and skip services, everything that rubs against something else inside the engine wears out faster. That's why I'm so particular about regular servicing. If you'd like to see the exact service intervals, I've explained them in detail in the Passat B7 service schedule and the A4 B8 service schedule.
A tip from Kris Mladenov: Do you drive an Audi A4, A5, A6 or Q5 with a 2.0 TDI engine from these years, and has it already covered more than 120,000 km? Bring it to us at Das Auto Service and let us check the oil pump drive. I'm telling you this because one check at the right time could save your entire engine.
I genuinely hope this article helps us save at least one engine. If you drive a 2.0 TDI, check whether your engine is one of those affected. And if you've got a friend who drives one, send them this article. You might save them a very expensive repair.
Read more
- Complete engine rebuilds
- Vehicle diagnostics
- Passat B7 and CC 1.6 and 2.0 TDI service schedule
- Audi A4 B8 3.0 TDI service schedule
- 2.0 TDI (EA189): EGR valve, EGR cooler and limp mode
- Timing belt kit with water pump: what's included in the genuine kit
- 1.9 and 2.0 TDI PD engines: the legend and its weak points
Frequently asked questions
Which 2.0 TDI engines have oil pump problems?
We're talking about engines with a balance shaft module that has the oil pump built into it. We see this most often on the Audi A4, A5, A6 and Q5, with engine codes such as CAGA, CAGB and CAHA.
How can I tell if my oil pump is starting to fail?
That's the worrying part, my friend. There are usually no early warning signs. The car drives perfectly normally. The red oil pressure warning light only comes on once the pressure has already dropped. Don't wait for your engine to warn you. By then, it could be too late.
Can I prevent oil pump failure?
Yes, and that's exactly what I recommend. We inspect the hex shaft that drives the oil pump. If it's worn, we replace it with an improved version or replace the entire module, depending on its condition. I want us to catch the problem before the pump stops working.