What should I do after an AFN engine failure? I need advice

'Hello, I'm having a problem. My Passat 35i (AFN) broke down this weekend. I was driving at 120 km/h on the highway with the cruise control engaged when I suddenly noticed a smell (diesel). After I turned off the cruise control, I realized that the car was only responding sluggishly to the accelerator. When I stopped at the exit, I noticed that the engine was running unevenly at idle (like it was only running on two cylinders), and it was very hesitant when I gave it gas (when there was boost, it was almost like before). It was also smoking a lot; the smoke was blue and, I think, smelled like diesel. So, I towed the car to my garage and checked everything I could. The turbo is fine; it was still producing boost (1.3 bar). There's no oil or water loss, the VTG is working smoothly, and the timing belt seems to be okay.' 'The engine is running smoothly (all markings aligned). The timing belt is still in good condition and no teeth are missing. The timing belt pulley is also securely attached to the crankshaft, etc. All hoses, cables, etc. have been checked, and everything seems to be fine. I initially thought it might be the diesel pump, so I took the vehicle to the workshop. According to the workshop, the pump is in good condition. They said that two pistons are likely defective. Is that possible? The mechanic said he doesn't need to measure the compression, but he would guarantee that two pistons are defective. However, he can perform a compression test if I want, to guarantee it 100% (which would cost extra). So, my question is: what should I do? Should I repair it or replace the engine? The car has 235,000 km (approximately 146,000 miles) and is in very...' Good condition overall. I'd prefer to install a replacement engine myself, as I can do that without any problems. What bothers me is that they all supposedly have only 80,000-90,000 km on them, and I find that hard to believe. It can't be that all replacement engines have been driven for less than 100,000 km. When you search for complete vehicles with these engines, you don't find anything with less than 180,000 km, and rarely, you might find one in 20 that has actually been driven less. These replacement engines aren't all from cars that have been driven sparingly; a TDI is often bought to rack up the mileage. Would it be worth repairing the cylinder head or the engine block, given the diagnosis? I'd like to drive this car for another 200,000 km. Of course, the cost is also a factor; it shouldn't cost more than 2000 euros.Ideally, I'd like to find a replacement engine (it's the beginning of the year, and it was just Christmas), or maybe someone has corresponding parts. The problem is that I don't have much time, and I urgently need the car. And if I'm going to repair it, it needs to be done properly; I don't want to have to start all over again in 10,000 km, meaning an engine replacement, etc. Oh, and of course, the error memory has been read multiple times: once with VAG-COM, once by the ADAC, and once by the workshop, and no errors were found.
Thank you in advance for any advice you can offer.

Best regards, THT.

Hello,

It's generally easier to read a text that uses proper capitalization and punctuation.
Since you can do your own repairs, if the compression test indicates piston damage, remove the cylinder head. Then you'll be able to see if the cylinder liners have been damaged, or if you just need new pistons. Replacing the head gasket isn't cheap, but it's not dramatically expensive either. If the engine is completely gone, for example, if the engine block is cracked, you can still install an alternative engine (AT engine).

Sincerely,
Christian

Hello!
As Chris11 mentioned, you have the advantage of being able to do things yourself. Finding a truly 'new' AFN engine is becoming increasingly difficult... the chances of winning the lottery or being struck by lightning are probably higher. However, within your budget, it should be possible for any engine rebuilder to overhaul your engine block and crankshaft, provided you supply the bare block. This would involve: reconditioning the crankshaft, installing new bearings, new pistons, and honing the cylinder bores. In the meantime, you can work on the cylinder head at home, doing the usual things: checking the valve guide clearances (which shouldn't be too worn...), cleaning and re-grinding the valves, replacing the stem seals, and installing new valve lifters. Then, if the turbo and pump are really in good condition, you should have a relatively good chance of driving another 200,000 km on diesel.
Regards,
Dominique.

It would be interesting to know why it broke down. Have the nozzles already been replaced? Tuning?

If the pistons were cracked, it would have likely seized up and stopped running!

Take a look under the valve cover to see if the hydraulic lifters are in good condition .

Okay, thank you for all the input. The defect is now 100% confirmed to be the fourth cylinder. I'll finally be able to bring my car to my garage tomorrow, and then I'll start taking the head off. I already opened the valve cover before to check the hydraulic lifters. On a different note, I have an AFN engine from a Passat 3B available that supposedly has only 112,000 km (which is quite low). However, no one here can tell me if it will fit. I think the engine mounts should be the same as mine, and the intake manifold, etc., but the problem is that the starter motor on the 3B is mounted on the engine block, not on the transmission. I'm not sure if that will work because the engine is a bargain from a friend.

Regarding the setup, with my current configuration, I had a different turbo (I don't remember the exact model name anymore) that produced a boost pressure of 1.3-1.4 bar;). AGR clipped or sealed, modified exhaust gas routing , etc. It lasted for a good 80,000 km with a mixed driving style, but I think the actual cause is more likely with the fuel injectors or the pump, which caused the defect.

... but no one here can answer whether it will fit. I think the engine mounts might be the same as from my car, and the intake manifold, etc., but the problem is that the DE3B engine has the starter motor mounted on the block, not on the transmission. I'm not sure if it will fit because the engine is a bargain from a friend, a friend, etc.

Hello!
That's why the starter motor is still bolted to the transmission, it just *looks* like it's on the other side because it's bolted on from the opposite side. However, I don't know if all the necessary threads for the other engine mounts are present; one of the VW experts here would need to answer that. 'You'll probably have to modify the flywheel, and likely the oil pan and the entire water pump assembly, as well as the timing belt cover... hmm... it's going to be a lot of work!'
I somehow almost envy you. When writing, and seeing the details unfold before my mind's eye, I actually get a tingling sensation in my fingers! That would definitely be a weekend project...
Good luck with your renovation!
Regards,
Dominique.

Okay, so it seems like I have some good and bad news. I took a look and found a crack running across the fourth piston. There's nothing visible on the cylinder head, and the cylinder walls don't seem to have any scratches or damage. In theory, you could just replace the piston and it would run again, but I'd also like to be sure it will last longer. I'm wondering what caused the piston to crack? What would be a sensible approach? Should I replace the entire engine? And additionally, for safety reasons, should I replace the fuel injectors, pump, etc.? Is this even worth it? Also, the AFN engine has a red sticker (indicating higher emissions), so you'd have to convert it to yellow, but I don't think that's a real advantage in the long run.

I would like to insert photos, but somehow it's not working.

I'm still unsure whether to go through with it, considering the costs and time involved. There's a risk of having to put it down, even though it's actually in relatively good condition.

"If it's already in that condition, I would replace the piston. You should have Rainer redo the nozzles, and you can see the PL bearing. If they're worn, just replace all four and you're good. Maybe the engine will last another 200,000 km, or maybe only 50,000 km, but you won't get much further with another engine or a different car either, aside from the red emissions sticker. So, I would invest the 500€." In my opinion, the AFN engine is the most economical and best diesel engine that VW has ever produced.

Sincerely,
Christian

moonlight wrote:

ok, thank you for the numerous responses. The defect is now 100% confirmed to be the 4th cylinder. I will finally manage to bring my car to my place tomorrow, and then I will take the cylinder head off. I had already opened the valve cover before to check the hydraulic lifters. By the way, I have an AFN engine from a Passat 3B available, which supposedly (at least according to the car's mileage) has 112,000 km. However, no one here can tell me if it will fit. I think the engine mounts are the same as mine, and the intake manifold, etc., but the problem is that the DE 3B has the starter motor mounted on the block, not on the transmission. I'm not sure if it will fit because the engine is a bargain from a friend. Regarding the setup, with my current configuration, I had a different turbo (I don't remember the exact model name anymore) that produced a boost pressure of 1.3-1.4 bar;). AGR clipped or sealed, modified exhaust system;), etc. It lasted for a good 80,000 km with a mixed driving style, but I think the actual cause is more likely with the fuel injectors or the pump, which caused the defect

.
Hello.
The engine from the 3B model doesn't fit because the mounting points for the water pump are different.
I still have some pistons, but I only need the weight.
Sincerely, Sure, here is the translation of the text from German to English:

"Dirk"

hello
Due to my very limited time (professional reasons), I can only work on it on weekends. Since I've found a great new project, I'll unfortunately have to let this one go, either by selling it completely or dismantling it. Briefly about the car: it's very well-maintained, second owner (me), complete service history, clutch replaced before Christmas along with the flywheel, turbo is practically new, completely tinted windows to the front (Foliatec SilverReflex), Vogtland sport suspension, new winter tires on 15' (installed 07/12), grill without emblem, accident-free, no rust, color is Dragon Green Pearl, manufactured end of 1996. Maybe someone needs a good body? It's a Passat 35i Pacific with air conditioning, TDI engine, and cruise control, and everything was working. As I said, if anyone is interested, please contact me before the weekend.Otherwise, I will be spending Saturday dismantling the car. I want to emphasize that the vehicle is in very good condition, as is the bodywork and all the parts. The engine has always been dry and has had oil changes every 10,000 km. It has zero oil consumption and zero water consumption. I'm saying that we can discuss all the prices, but I'm not giving the parts away. I need to make approximately €1500 in total.
Here's my phone number: 0172/2163062. If you tell me your email address, you can have the photos. The car is located in a garage in 50996 Cologne-Rodenkirchen. Sorry if the text isn't written the way some people might prefer, but I'm completely exhausted (and having trouble concentrating).

Best regards, Thorsten.