Hydrostössel V6 TDI AKN | Posts 16+

It seems I'm not the only one having this problem; Christians (a professional here) also received 5 broken ones (out of 24).

Herr Antje wrote:

However, I am convinced that if I were to have the hydros checked now, there would again be some that, according to the test, are not 100% perfect.

and so it probably is . The broken ones could be inflated again, but if the oil pressure was gone, they would compress again.

My engine isn't running as smoothly as I'd like. The valve timing is correct, the exhaust smoke device (ESD) is new and adjusted, and the fuel injection timing is 100%. I don't know if the injector seals are sealing properly (how would I check?), and the glow plugs are sealing (checked with soapy water). I've driven about 5-8,000 km now. The idle speed control is just within tolerance for one cylinder, but it needs less diesel .

Since the hammering is quite loud, I'm not sure if I can hear whether my hydropneumatic accumulators are actually making a clicking sound. Could someone perhaps tell me if a loud popping noise could also be caused by the hydropneumatic accumulators?

It seems worse at low RPM than at high RPM (but it might also be my imagination). This could possibly be because the hydraulic lifters aren't retaining pressure, and the oil pressure only builds up sufficiently at higher RPM. But that's just speculation...

"If the hydraulic components are extremely soft, the valves will open for a shorter duration and to a lesser extent. If this happens to affect one or more of the swirl channels – the AKN (likely referring to a specific engine component) has both a swirl and a tangential channel – it will certainly hinder the intended swirl formation, and thus negatively impact the combustion process. However, I cannot quantitatively assess the relationship between this and the engine's running characteristics."