AFN Engine: End of Production?

Hello,

First, let's start with the background.
Approximately 500 km ago, I changed the oil, and the oil filter was completely clogged with oily carbon, right to the top. The consistency is similar to that of saturated cotton balls. If you dry it on paper, removing the motor oil, it resembles diesel soot.

I regularly check the oil level, maybe every 2-3 thousand kilometers, but during the oil change after a slightly exceeded 15,000 kilometers, only 1.5-2 liters came out, including the filter. So, a significant oil consumption in a short time, but it wasn't producing any smoke. I did have some thoughts about whether the bypass valve around the oil filter had opened, as I don't know how long the oil filter has been clogged, and this thick, black sludge could be settling everywhere. After consulting with other, more experienced mechanics than myself, I should avoid using cleaning additives and continue driving carefully, and I should bring the next oil change forward to 3,000 kilometers. I've been using a semi-synthetic 5W40 oil so far. After 200 kilometers, the turbocharger failed, likely due to oil starvation, and it "died" by sending engine oil into the intake area. I noticed this in time, so there were no further damages. I installed a new turbocharger, tested it briefly, but then the oil pressure light came on soon after, and the engine started running rough, so I didn't want to continue testing and finally wanted to see what was going on.
Okay, so I got up on the lift, removed the oil pan, and that's when I saw it: the entire lower area, everything you can see when the oil pan is off, was covered in about 1 !! CM !! of sludge. Even the large weights attached to the pistons were covered with maybe half a millimeter of sludge. Of course, the oil pump and its strainer were also heavily affected. The strainer was completely clogged, which I had suspected. I cleaned everything as best I could from below until it was shiny again, and then installed a new oil pump. I put the oil pan back on. I actually wanted to use a cleaning solution (MotorClean from LiquiMoly) now, but the workshop foreman had better arguments against it, and we decided to check it again in 500 km.

"Oil pressure is present, but the 0.9 bar pressure switch doesn't engage at 2000 RPM. The engine runs smoothly, quietly, and evenly, at least for the 80 km I drove it. I haven't checked the power output. At a constant speed of 85 km/h (my maximum speed), it suddenly started to make a quiet rattling noise, similar to the sounds in the audio files in this forum post."

I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.

So, with half the engine speed, but getting louder quickly.
Of course, I immediately pulled over to the right and let out the clutch. While stopped, the engine was then swinging back and forth quite strongly, with an excursion of maybe 5cm. I definitely checked and all the engine mounts were securely fastened! But that soon lessened. When I gave it a little gas to 1000 RPM, it went away, but the rattling remained. I'm almost afraid to write this, but something then briefly creaked or cracked, like something was shearing. Since then, it's been running more quietly again, aside from the faint rattling that's still there.

Well, I have a feeling that I'm not going to get anywhere with this engine. Just waiting and hoping that the (now fully synthetic) 5W40 oil will somehow "fix" the problem on its own is probably not going to result in the engine running cleanly.



Genaugenommen kann er durch die 200km Ölmangelfahrt (0,3bar-Öldruck wurde immerhin überschritten) so ziemlich in jedem Lager einen Vorschaden haben, befürchte ich. Ist Is there anything to salvage?
It seems that simply eliminating the noise isn't addressing the root cause, and even if I fix that, another bearing might fail 100 km later. And continuing to drive like this, until the engine completely breaks down, isn't a good idea either. Ideally, you should thoroughly disassemble the engine, flush all the oil channels, and inspect all the bearings, or even replace the entire engine.

"Does anyone have any ideas about what might be wrong with the engine? I'm suspecting a blown head gasket, but there aren't any obvious signs of it, like excessive smoking, coolant loss, or brownish oil. The oil is black. The dirt has to be coming from somewhere. I'd appreciate any insights."

Okay. I read the error codes, but I didn't find any relevant ones. (My driver's side door sensor isn't working, but that's probably unrelated to the rest of the system.)


Greetings.

Udo.

Quote:

Does anyone have any idea what might have happened to the engine? I'm leaning towards a blown head gasket, but there aren't any obvious signs of it, like classic symptoms such as smoking, water loss, or brownish oil. The oil is black. The dirt has to be coming from somewhere. I'm grateful for any information.

Dazu müssten schon mehr Infos zum Motor, dem verwendeten Kraftstoff, sowie Motoröl, Fahrprofil, Laufleistung und evt. TI'm not sure what you mean. Could you please rephrase your request?

I could also imagine that happening with a very low-quality engine oil that has a high evaporation rate.

Hi BM,

The engine is a VW TDI, AFN, 81kW. For the last 30,000 km, I've been using diesel fuel. Before that, I experimented with vegetable oil for 30,000 km until the fuel injection pump failed. There might be some deposits, but there have already been two oil changes in between, right?
Motoröl ist immer 5W40 gewesen, hydrocrack-Synthese, also sog. teilsynthetisches, Qualität laut Verpackung CF. Fahrprofil: absolut zurückhaltend. Seltenst über 2000 Touren, meistens Mittelstrecke, 100km. Die Laufleistung beträgt 230tkm. Kein tuning.

"I was able to discuss the whole situation with a professional today. He shares my opinion that, based on the history and the noises I'm hearing, all the bearings are damaged, and a "motor failure" is only a matter of time. This means my hope of finding a simple solution has been dashed for now. But there's a silver lining: if I get a replacement engine, I can enjoy the car again for a while without having to worry."

Greetings.

Udo.

Quote:

He shares my opinion that, based on the history and the background noise, all the bearings are damaged, and the "motor failure" is just a matter of time.

Well, it's quite negligent to continue driving with an engine in that condition. A basic cleaning probably would have prevented more serious problems.

It's possible, though, that you got lucky. The noise coming from the engine sounds more like a lifter problem to me than a bearing failure. Before I would install an AT engine in that old car, I would first check the connecting rod bearings and the crankshaft journals.

Hi,

To enjoy your car for a longer time,
I can only recommend a complete disassembly and cleaning of the engine.

Inspect the parts and replace at least the following components:
- Oil pump
-Plain bearings
- Hydraulic lifters

Given that the pressure relief valve in the oil filter likely opened, and unfiltered oil was pumped into the engine, the extent of the damage is unpredictable.