"An engine failure" usually means one. "Engine failure" could be something that affects multiple engines. But they are generally interchangeable.
I found some examples containing both "due to an engine failure" and "due to engine failure", and I don't understand why both patterns are used.
The Condor Liberation ferry was cancelled on Saturday evening due to an engine failure
What happens after a plane makes an emergency landing due to engine failure?
A common explanation I have come across is that "due to engine failure" refers to the general phenomenon of something/someone failing, while "due to an engine failure" refers to a specific occurrence of that phenomenon.
However, I have difficulty understanding this distinction. Those three examples are all referring to specific cases (including a hypothetical case and actual accidents), so to me, the engine failure in each example already seems to be a specific occurrence.
I don't understand how "engine failure" without an article can be used in these contexts if it refers to the general phenomenon.
One additional thought: is it possible that, strictly speaking, "an engine failure" is more precise when referring to an actual individual occurrence, but native speakers often use "engine failure" as a general shorthand because they are focusing on the cause rather than counting the individual occurrence?
In other words, is "engine failure" sometimes used in contexts where "an engine failure" would also be possible, simply because the speaker is not focusing on the failure as an individual event?
"An engine failure" usually means one. "Engine failure" could be something that affects multiple engines. But they are generally interchangeable.
You can use them interchangeably in almost any situation. An engine failure might be more precise in something like a large plane or ferry that has multiple engines. If you were describing a series of failures you would skip the article, even if not explicitly making it plural failures. "Brand X cars are frequently scrapped early due to engine failure."
I would understand:
This seems consistent with your examples.