It is commonly said that engines running propane, vs gasoline, last longer.

Taking out the factors such as application, I am inclined to think this is because upon cold start, the propane engine does not require a rich fuel mixture. The rich mixture might result in condensation on cylinder walls in a gasoline engine. And in a diesel engine, fuel may be sprayed and may collect on the cylinder wall prior to engine start. But in a propane engine, the vapors, at least in temperatures above arctic temperatures, are unlikely to condense on the cylinder walls. Without the washing of the cylinder walls, there is less start-up wear.

My assumption is that this is the primary reason for longer life with propane as the primary fuel.

My question is: Is there research to back this up (or refute it)? Of course, some cites would increase credibility of any answer.

  • What have you found so far? So we don’t waste time finding stuff you already have...
    – Solar Mike
    Commented Jun 7, 2018 at 13:18
  • Nothing. That is why I am asking. I have not done a peer reviewed literature search, which is a gold standard. However there are probably people who have good subject matter understanding, which is why I ask. The cold start theory I floated, has always been my assumption, but I don't know for certain. There are other theories, which I did not mention, such as the "clean fuel" theory, which I discounted. The cold start theory interlaces with longevity in diesel engines, including frequent cold start applications.
    – mongo
    Commented Jun 7, 2018 at 13:27
  • Here is a theory : people running propane tend to treat the car with more care and don't accelerate as hard so improving engine life...
    – Solar Mike
    Commented Jun 7, 2018 at 13:56
  • I think you'll find the longevity in diesel engines is no more, due to expensive fragile injectors, failing turbochargers, clogging EGRs, dual mass flywheels and exhaust gas treatment technology like diesel particulate filters and selective catalytic reduction. In contrast, the longevity of naturally aspirated gasoline engines has increased due to longer-lasting ignition system components and none of that high-tech that is required for diesels. As for propane, I'd be interested to see an answer to this question.
    – juhist
    Commented Jun 7, 2018 at 14:03
  • Wikipedia seems to agree with you: en.wikipedia.org/wiki/Compressed_natural_gas says "Increased life of lubricating oils, as CNG does not contaminate and dilute the crankcase oil."
    – juhist
    Commented Jun 7, 2018 at 14:09


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