Which PD-TDI engine is recommended?

Hello,

'I'm planning to buy a new car soon, and I'm flexible about the brand, but it definitely needs to be a VAG TDI. Since I like to drive quickly, the 100 hp PD engine isn't really my favorite. I'm not hearing good things about the reliability of the 1.9 TDI (150 hp), even though many parts are supposedly reinforced specifically for that engine? The V6 TDI (150 hp) is said to have extreme problems with the mass airflow sensor. The V6 (180 hp) is simply too expensive for me. That leaves the 130 hp TDI; I hope it combines sportiness and reliability. Perhaps someone with experience or knowledge about these engines can chime in. Would it be able to handle an additional 30 hp from a tuner?' Who here is driving a newer generation Porsche Diesel?
@ulf, you once mentioned a very specific problem with pump-injector engines (was it about the timing belt?). It would be great if you could briefly explain it again.
Best regards, Steffen.

Hi.

Quote:

@ulf You once mentioned a very specific problem with pump-nozzle engines (was it about the timing belt?). It would be nice if you could briefly explain it again

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I have mainly 3 reservations about PDs, which are related to the sometimes extremely high material requirements.

1. You need to use special PD oil because regular broth would quickly wear out the drive cams of the PD elements due to the surface pressures.

"The cooling system for the extremely hot fuel return line back to the tank seems unnecessarily complicated and therefore prone to failure. If it malfunctions or breaks down, the tank could be damaged when the engine is running hot." Not only do you end up stranded, with the expensive fluid leaking out, and the repair being guaranteed to be expensive - no, you probably also have to deal with the costs of cleaning up the contaminated soil.

(Considering VW's general reputation for reliability, I wonder why cases like this haven't come to light sooner. Is it possible that the VAG group pays hush money to prevent embarrassing publications about environmental design flaws, or is my assessment simply wrong/too pessimistic?)

"The timing belt, which is already quite thick, is stretched during the pressure build-up in the PD (positive displacement) elements to such an extent that its tooth pitch no longer matches that of the crankshaft sprocket." Therefore, when the belt comes into contact with the toothed wheel, the flanks of the teeth would experience significant friction, and the belt would not achieve a significant lifespan – unless the tooth size on the toothed wheel is increased accordingly.
This "design flaw," in particular, suggests to me that the focus was on aspects unrelated to the core functionality: Why wasn't a solid, reliable tax chain implemented from the beginning?
To potentially make the car 20 kg lighter and 200 euros cheaper at the initial sale, while simultaneously extracting a multiple of that amount from the customer with every belt replacement??? What he only realizes when it's "too late," because he's already bought the box...

Hi, I don't own any of the newer PD models, but I have one with 115 horsepower that's been chipped, and it works great. The 130 horsepower version seems like the best compromise and is also supposed to be suitable for tuning. The 150 horsepower version is pretty much at its limit and seems to have more problems, which some people also report. The engine's running smoothness is also supposed to be worse than the 130 horsepower version. Furthermore, the extra power compared to the 130 horsepower version isn't really noticeable until above 3000 rpm, which, according to the speedometer, corresponds to just under 170 km/h in 6th gear on the highway. Some VAG dealers even advise against the V6 engines, because they supposedly have other problems besides the mass airflow sensor, but I don't know the details. The 130 horsepower version is also more powerful and responsive at lower RPMs than the V6 TDI. After careful consideration, I would definitely buy the 130 hp TDI model and have it tuned by a reputable and reliable tuner. Then, in no situation does the small 2.5 TDI engine stand a chance; the fuel consumption is lower, and the taxes and insurance are also cheaper.

Hello Ulf,

The complex fuel cooling system (using a cooling circuit), as described by Bosch in its documentation, is not used in VW PD engines (including the 150 hp models). Here, the fuel is passed through an air-cooled fin cooler.

Michael II wrote:

The complex fuel cooling system (using a cooling circuit), as described by Bosch in its documentation, is not used in VW PD engines (including the 150 hp models). Here, the fuel is passed through an air-cooled fin cooler.

Hi Michael,

Then I wonder why the self-study material about the AJM engine describes a water-fuel cooler with a temperature-controlled electric circulation pump for the coolant... isn't that no longer standard equipment, or was it never built in series?

Hello Ulf,

According to the parts lists, none of the above-mentioned items include... PD Motors, one.
Fuel cooling system uses water. Also, even with my AJM.
There is only air cooling available.
What is the current revision status of your documents?

Hello Ulf,

Water cooling was only available in Audi models, specifically the A4 and A6.
equipped for the model years 1999 and 2000.
After that, only air cooling.

Hi Michael,

My information is current as of December 1998. I happened to acquire them once, but I'm not receiving any regular updates.

Hi Steffen!

I've been driving an A6 Avant TDI with the 130 hp TDI engine (engine code AWX) since January, and I've driven it approximately 5,000 km since then, mostly on the highway.
I'm completely thrilled with it. Even an A6 Avant, which is quite heavy, feels very agile. I took it out on the A7 last weekend and reached about 235 km/h according to the speedometer. The speedometer indicates speeds where driving between 180 and 200 km/h feels most comfortable.
The fuel consumption is then around 7.5 to 8.0 liters per 100 kilometers, which is perfectly acceptable.
'To date, there is no evidence of any oil consumption. While the PD top-up oil is very expensive, according to the user manual, only a maximum of 3.5 liters is required after an oil change. I find this to be an extremely small amount, as Daimler-Benz, for example, uses oil quantities of around 6.0 liters in comparable diesel engines.' This, in my opinion, shows that one must be very sensitive to oil consumption.
I can't say anything about its long-term durability yet.
My Golf III Variant, which is not chipped and has a 90 hp TDI engine (engine code 1Z), has now reached 201,000 km with the original mass airflow sensor and fuel injectors.
So far, there have been no reported outages.

Hi,

I would like to ask a question. If the 150 hp PD engine is so prone to failure, how can I assume that a 130 hp PD engine (which is likely not as optimized for 150 hp performance as the original 150 hp PD engine) will not be as susceptible to failure when tuned to 150 hp?

Are there any reasons for that?

Okay, I understand. Please provide the German text you would like me to translate into English. I will only provide the translation.

I just made a mistake.
Okay, let's go again.

I would also be very interested in the answer.
Why is the 150 PD supposedly more susceptible to issues?

So, regarding the question of why the 150 HP version is more prone to issues, I've asked my chip tuner about it multiple times, but there's no concrete answer. The fact is that there are no problems with the tuned 130 HP version, but the 150 HP version tends to fail more often even in its stock configuration. A similar situation exists between the RS 4 and the S 4. The S 4 undergoes complete modifications with larger turbos, performance camshafts, cylinder head modifications, etc., so that the power and torque are almost at the RS 4 level, and they hold up well. Meanwhile, the RS 4 also has durability issues even in its stock form. But ultimately, no one knows exactly why this is the case. It probably depends on certain design features.