Today I heard from a Turkish analyst that the Chinese tank engines were extremely unreliable. He claimed their average lifespan was less than 1000 hours. The said analyst is a knowledgeable and respected person so I don't think he is lying. But I think he is misinformed as I couldn't find evidence supporting this. Do any of you have knowledge?
I'll try a different angle because I think you are painting yourself into a corner with your thinking:
Here's a comparison of tank engines relevant to my home region in eastern Europe - W92, 6TD and MB873 are diesel engines, AGT-1500 and GDT-1250 are gas turbines:
The term "lifespan" in the context of tank engines should be understood as "
service time before rebuild". All tank engines are designed with a specific time at specific thermal loads before chemical and physical wear on components greatly increases failure rate. That lifespan is a calculated design parameter.
Depending on your strategy you design cheap short-lived engines or expensive long-lived engines. In the context of warfare neither is a "bad" or "good" choice as long as for every engine with 2x the lifespan at 2x price you have two engines with 1x lifespan at 1x price.
There is another design parameter of "
mean time between failure" which is more important for operational and tactical considerations. This parameter often limits the practicality of building stronger engines using the same technology if the increase in power comes at the cost of their reliability because while it is not a problem to change engines during rotation of tanks out of battle it is a critical problem if the "better" engine has a higher mean failure rate causing it to fail while in combat.
This causes tank engine development to have stepped evolution. More powerful engines are not introduced unless their mean time between failure remains within acceptable bounds and because failure rate is correlated highly with energy generated those increases of power usually are connected with new designs that improve reliability as well as power output.
However while new designs can have better parameters they require re-tooling and re-training of technical crews and they require stocks of spares for continued operation. If you swap engines in an active unit you need to swap engines in reserve units and reserve materiel stocks and have to re-train active duty soldiers and reserves.
Modernizing tanks is always about modernizing fleets of tanks and their operators because there is so much interchangeability between vehicles and people that anything less disrupts the entire ecosystem. German tanks in WW2 are the best case study of what not to do. China seems to be going the Soviet way which is undeniably crude but proven to work.
Soviet designs were deliberately designed with lower lifespan to reduce cost because Soviet planners continued their approach from WW2 of designing the engine around the lifespan of a tank. Soviet strategy called for mass production of tanks and assumed mass losses (all causes) so long-lasting diesel engines were not necessary. Because in Soviet Union resources for production and fuel were plentiful there was no reason to economize their efficiency nor the efficiency of production. There was also no reason to improve efficiency of engines because Soviet union deliberately chose to build more of smaller and lighter tanks which automatically meant lower energy requirement. This is why Soviet designs stayed at a lower technological level than their western counterparts.
At the time China benefited from both the mass production/deployment strategy as well as from lower technological requirement as it was only beginning to industrialize. When USSR collapsed China suddenly lost its main land threat and with that the pressure on modernization of land force shifted. Even now modernization of tanks is not the biggest priority because tanks are not the kind of weapon that most people imagine them to be.
Tanks are breakthrough weapons, and in particular they are the weapon used after the breakthrough occurs and your forces can exercise maneuver in the the enemy's rear. That is when tanks shine on the battlefield. Other than that they are not very useful on their own and are vulnerable to logistical disruption. An immobile tank is a neutralized tank and it is much easier to immobilize a modern tank than to destroy it.
Which is why it is not a bad decision to forgo intensive development of better tank engines if you can keep the tanks running with worse engines. Communications, targeting and ammunition are of much greater importance. In terms of mobility transmission and suspension provide leaps in capability. Transmission is responsible for acceleration which is all about moving in and out of position. Suspension provides stability for targeting and protects the crew from being rag-dolled to death. Better lifespans for engines mean primarily one thing - the tank can get bigger than 55t. Because that's the parameter which correlates with why MB873 is such a good engine. The lifespan is not the goal but a
by-product of the engine parameters which produce high energy output, high peak and mean power and tolerable thermal loads. Those are much more important when the tank is as heavy as Leopard 2 and has mobility required of Leopard 2. That mobility requirement was caused by the staggering
numerical and technological superiority of Soviet armor. Germany had no other option. They had to equalize with a ridiculous dash in combat capabilities and absurdly high reliability.
China doesn't.
This is also why when recently Russians modernized their T-72B fleet they focused on new radios, thermal cameras and new ammunition. Tanks are not jet fighters. They don't fight duels one-on-one like in the movies. They work in packs and either pin enemy forces in position like in chess/go so that artillery can wipe them out or raid the rear where nobody has good anti-tank weapons and so they have to disperse or flee disorganizing the entire logistical network.
Hope this helps.
As a parting note - always consider the context before considering the contents of the message.
As Sun Tzu once said:
on Twitter the correct answer to "Chinese engines don't last 1000 hrs" is "Still longer than Turkish Lira". 
