Are TDI miles actually more expensive than we'd like to admit?

Hello everyone,

Over time, some practical experience has emerged regarding the lifespan of more expensive TDI parts. As a result, I've done a rough long-term cost comparison between my tractor and a compact gasoline engine in the 150 to 200 horsepower class.
For this calculation, I only included the prices for engine-specific replacement parts (excluding labor costs except for timing belt changes), fuel costs, and taxes.

Depreciation and insurance were excluded due to high uncertainties, as were minor items such as tires, filters, and oil, which are generally required for both diesel and gasoline engines and therefore largely offset each other in the comparison.

And that's why the TDI balance sheet made me think a bit. If you replace the wear parts of the fuel injection system before there is a significant deterioration in performance, driving characteristics, and fuel consumption...
Replacing the injectors and glow plugs every 150,000 km, the fuel pump every 200,000 km, the timing belt every 90,000 km, and the mass airflow sensor every 100,000 km increases the cost per 100 km by about 2 euros – roughly half of my pure fuel costs!

For gasoline engines, the only specific sealing components that immediately come to mind are spark plugs: high-quality ones costing around 50 euros each, and needing replacement every 60,000 km, roughly equal the cost of glow plugs for a diesel engine = peanuts.

Compared to the TDI engine, which costs 9.10 euros per 100 km, my gasoline engine model, which has about 60 horsepower more, doesn't seem that much worse at 10.60 euros per 100 km, especially when you factor in taxes.
Okay, I only drive about 10,000 kilometers per year; at 20,000 kilometers, the difference would be roughly €2.50 per 100 kilometers.

On the other hand, for those who don't do DIY and have to take their car to a workshop for every job, the balance shifts back in favor of gasoline engines due to the often more time-consuming and therefore more expensive repairs on diesel vehicles.

Just curious (and hoping to connect with colleagues who have similar experiences):
Are there similar hidden issues and problems in current high-performance gasoline engines, especially turbocharged ones, as there are with TDIs (such as short-lived mass airflow sensors leading to significant power loss, jerking, AGR buildup, unfortunately frequent head gasket failures, and engine deaths due to broken timing chains, etc.)?

Please don't throw stones at me, you hardcore TDI enthusiasts, but in my opinion, amidst all the excitement, one should also try to make objective assessments from time to time...

Hello Ulf,

You are absolutely right. In my opinion, the biggest weakness of diesel engines is also the susceptibility to failure of certain components.
One can only hope that nothing breaks .
I would only advise you, if you're switching to a gasoline engine, not to choose one with direct injection (FSI). With those engines, you experience problems with expensive components and clogged intake ports in a more severe form. If a naturally aspirated gasoline engine doesn't get enough air, the loss of power is REALLY noticeable. Deactivating the EGR system isn't as straightforward on a gasoline engine either, because it significantly reduces fuel consumption at partial loads.I've also heard from several acquaintances who drive gasoline-powered cars about faulty mass airflow sensors.

Best regards,
Albrecht.

The turbochargers are also a weak point in the gasoline engine. A friend of mine had to replace them on his 1.8T with 150 hp at around 120,000-130,000 km. It's quite obvious that this isn't going to be cheap.
I don't know whether modern turbochargers still use these mass airflow sensors or in what way, but the older ones weren't exactly reliable either.

I'm not sure if I missed it, but the timing belt needs to be replaced every 90,000 to 120,000 km on gasoline engines as well, depending on the model. As you mentioned, spark plugs aren't that expensive.

When comparing insurance costs for diesel and gasoline engines in the 150-200 horsepower range, my experience suggests that the differences are often not as significant between gasoline and diesel models. However, this can also depend on the specific model.

However, for someone driving 10,000 km per year, I wouldn't buy a diesel car. In my opinion, the calculations and figures used to promote diesels in such cases are misleading.
Für mich hat ein leistungstarker Benziner nämlich immer noch den besseren Fahrspaß, das ist sicherlich subjektiv, also nicht streiten.

Assuming I work approximately 240 days a year and drive about 120 kilometers per day, that alone adds up to roughly 28,000 kilometers annually, without even considering any personal mileage. In that case, diesel definitely seems like a worthwhile option.

Hello,
I also believe that the low fuel consumption of TDI engines should not be overstated. It's not just taxes and insurance that are higher for diesel vehicles; other factors like shorter oil change intervals, higher repair costs, and, above all, a higher purchase price add up significantly.
'I drove about 50,000 km last year, so a diesel definitely makes sense in my case. However, I'm now considering whether the next one should be a TDI or a CDI, because TDIs seem to have a higher rate of repair issues. There's probably a reason why most taxis are Mercedes-Benz (please don't judge), it's likely due to cost-effectiveness rather than prestige.'
I recently drove the current A6 and was a bit disappointed. The engine is louder than my 5-cylinder in the C4, and the suspension felt quite bumpy. As someone who's usually an Audi fan, I wasn't convinced by the overall quality. I think Mercedes and BMW are ahead in that regard.
Regards,
Martin.

Hello,

I mean that TDIs only unlock their full potential for cost savings if you can do almost everything yourself. In an (incompetent) workshop, you can get ripped off with a TDI.

Best regards, Rainer.

Hello,

However, this can also occur in gasoline engines. A very common workshop error is "Lambda sensor control exceeding regulation limit."

Most of the time, things are exchanged.
1. Oxygen sensor (approx. 170 EUR)
2. Fuel injectors (approximately €45 per piece, depending on the engine).
3. Occasionally, even the cat.

In 99% of cases, the problem is a faulty fuel pressure regulator (or a malfunctioning vacuum control system for it). This part costs only about 17 EUR.

martin119 wrote:

Hello, However, I'm considering whether the next one should be a TDI or a CDI, because TDIs don't seem to be the most reliable in terms of repair frequency. There's probably a reason why most taxis have a Mercedes star (please don't judge), and it's likely for safety reasons because it makes economic sense, not for prestige. I think Mercedes and BMW are ahead in that regard. Regards, Martin

You might be mistaken about that. Mercedes and Volkswagen use the same parts for many components of their diesel engines, such as turbochargers.
My uncle is even getting his E-Class E270CDi replaced after less than a year, because the car was constantly running in "limp mode," the electronics of the communication system didn't work even after a complete replacement, and the engine still wasn't working properly despite various repairs. Furthermore, he was constantly annoyed by the car stalling and not starting again.

So, be careful with the claim that everything would be better at Mercedes. The electronic problems there are enormous. Of course, this also leads to correspondingly high repair costs...

@martin119

Is BMW supposedly in the lead? I can name you five people right off the bat who have only had problems with them.
'These BMWs have everything, from head gasket issues to multiple connecting rod failures. According to BMW, the head gasket is even considered a consumable part, and if it fails on a new car with only 14,000 km (approximately 8,700 miles), the customer has to pay for it themselves. I can't say how Mercedes compares, but compared to BMW, I prefer the VW/Audi TDI engines.'
relatively minor defect (what's a faulty VTG charger compared to a complete engine replacement?).

martin119 wrote:

.... kürzere Oelwechselintervalle ....

That's why all new TDI models have a maximum oil change interval of 50,000 km, while gasoline engines have an interval of 30,000 km. So, in my case, the gasoline engine is clearly at a disadvantage.
Even though I followed a strict maintenance schedule, my first oil change was already due at 15,000 km, which is comparable to what's required for a gasoline engine.
The days of shorter oil change intervals are long gone.


A diesel car needs to be driven for at least 20,000 kilometers per year in order to offer cost savings compared to a gasoline-powered car.

However, the gasoline engine performs poorly in a specific case: when used to tow trailers (e.g., caravans). To get a comparable gasoline-powered towing vehicle, I often have to opt for the largest engine available, which already increases the purchase price and insurance costs significantly. When you factor in the much higher fuel consumption of the gasoline engine, even with low mileage, diesel becomes the more economical option.
By the way, there are also relatively inexpensive TDIs when it comes to insurance classification! My AXR estate car is rather on the lower end of the scale with KH14/VK15. All gasoline engines are more expensive to insure (this only applies to the estate - the sedan is more expensive!).

.... kürzere Oelwechselintervalle ....

A diesel car needs to be driven for at least 20,000 kilometers per year in order to offer cost savings compared to a gasoline-powered car.

However, the gasoline engine performs poorly in a specific case: when used to tow trailers (e.g., caravans). To get a comparable gasoline-powered towing vehicle, I often have to opt for the largest engine available, which already increases the purchase price and insurance costs significantly. When you factor in the much higher fuel consumption of the gasoline engine, even with low mileage, diesel becomes the more economical option.

As someone who commutes for work, I can only agree with you. I currently drive about 120 km daily to and from work. Soon, I'll be driving approximately 400 km twice a week. For me, only a diesel engine makes sense! And for caravans/trailers, there's really nothing else.

joergs wrote:

fahre momentan ca. 120km täglich zu arbeit und zurück. bald dann 2mal die woche ca. 400km. da kommt für mich nur ein diesel in frage ! und für den wowa gibt es eh nichts anderes !

Hi Jörg,

For me, it would probably only be a diesel that comes into question or only a diesel.
I had ordered a car because I was facing daily commutes of around 180 kilometers (approximately 2 x 90 km) to work, but things turned out differently -> it ended up being about 40 kilometers per trip.

My limited calculations (considering wear and tear items, fuel, taxes, and DIY maintenance) still show the cost advantage of the TDI engine, but sometimes I find myself drawn to subjectively more appealing gasoline engines (small, powerful, and "still" relatively inexpensive), such as the Astra OPC or the announced Ibiza Cupra with 180 horsepower, etc.

On the other hand, my tractor embodies almost ideally my expectations for everyday driving pleasure: it has good torque even at low RPMs, the "limited" top speed doesn't bother me (and even keeps tire costs in check ), compared to modern new cars it is still puristically light - and it has a pulling power that gasoline engines usually need to provide with many more horsepower, with corresponding consequences for fuel consumption.If only the potentially exorbitant repair costs related to the engine weren't a concern...

Hello Ulf,

Quote:

Wenn nur die latent drohenden Horrorpreise für Reparaturen rund um den Motor nicht wären . . .

If that's the only thing you're worried about, I think you can safely keep your golf club.
How many kilometers does it have on it now? 50,000 km?
My car now has over 150,000 km on the odometer, and it's not exactly being treated gently; I tend to drive at full throttle on the highway whenever possible.
So far, only routine maintenance repairs have been necessary (brakes, timing belt, glow plug).
Furthermore, with a new car, you again have the high depreciation, and you can't possibly spend that much money on broken parts .

Best regards, Albrecht.

Hello Ulf,

Just stick with your TDI. The days when gasoline engines were cheap to repair are long gone (e.g., you could find an Opel C-Kadett 1.2N engine for scrap metal prices and then add another 50 DM for gaskets and small parts). You can expect that the TDI will easily reach around 200,000 km before any major issues arise.
You're not likely to find a reasonably reliable gasoline engine that can last over 200,000 km at Ford or Opel, and they aren't exactly cheap elsewhere either. VW/Audi VR6 or 1.8T engines are also problematic; I see the potential for repair costs as being just as high as with a 1.9 TDI.

Best regards,
Christian.

Hello,

On the older VR6 engine (engine code AAA), the following components were prone to failure:

- Idle stabilization valve (approx. €400).
- Circulation pump (approx. 80 €)
- Coolant flange with sensor housing (approx. 20€).
- Knock sensors (approximately €15 each).

And if you want to replace the timing chain including the tensioner, you can remove the transmission.

Hey everyone,

Based on my own (painful) experience, I can only agree with Ulf.

My A4, with its 1.9 TDI PD engine, costs only €650 per year more in taxes and insurance compared to a 1.8L engine, and €600 more than a 2.4L engine.

In addition to that, diesel engines have almost double the maintenance costs and a higher purchase price.

While it is true that diesel vehicles sometimes experience less depreciation, this is only partially accurate. The oversupply of used diesel cars means that supply and demand play a significant role, resulting in diesel cars being cheaper than comparable gasoline-powered models.

Best regards, Jürgen.

Juergen wrote:

While it is true that diesel vehicles sometimes experience less depreciation, this is only partially correct because the oversupply of used diesels means that supply and demand dictate prices, meaning that diesels are often cheaper than comparable gasoline-powered cars. Greetings, Jürgen

.

I can disprove that from my own experience. I was looking for a Golf 3 TDI, specifically the AFN model. Unfortunately, used cars with under 200,000 km were simply too expensive for me.
After a long search, I finally found a 1Z model from the year 1996. A comparable gasoline-powered version with either 90 or 115 horsepower (GTi) could have been purchased for about €1500 less. The market is flooded with those. This particular 1Z cost me only €3900, but it has a parking damage on the front.
I could have gotten a GTI that was 1.5 years newer, with the same equipment and no damage, for €3,000-€3,500, and it would have even had almost 50,000 km less mileage.

Okay, diesel vehicles tend to depreciate less in value, and there's certainly no saturation point with well-maintained used diesels on the market. Diesel cars are often driven until they reach the end of their lifespan, whereas gasoline cars are frequently sold even with relatively low mileage.