I’ve noticed Honda puts an emphasis on reducing stress. I have a 20 year old Honda which still runs fine because everything about it seems “overbuilt” - other owners say it runs fine without coolant, oil, etc - just keeps plugging along.
You reminded me of a stunt/promotion I saw on TV in the 1970's where they drained the oil from a Japanese import and then ran the engine (red-lined it as I recall, perhaps a brick on the accelerator) until they blew the engine.
This was when there was a lot of grousing about those cheap (and fuel efficient!) Japanese cars catching on in the U.S. market.
Hilariously, the Japanese car just kept running and they had to intervene — maybe drain the radiator?
I wish I could find something about it but even ChatGPT comes up empty handed. Maybe it was a half-time stunt? I feel like it was in a stadium anyway.
Depends on what you are asking of the engine. An engine at red line but under no load doesn't generate that much heat, and so can get by with no coolant, and run for a long time on just the oil film left after draining the oil. This is really bad for the engine and it will wear out much faster - but it will run for a surprisingly long time.
These are random little examples that might work in theory. Sure, a car can idle for an hour without coolant probably in the winter, possibly.
I can't be driven on the street in any meaningful way anywhere but a Minnesota winter.
If you can't drive to work 20 miles away in 75 degree weather without coolant, than no a car can't run without coolant.
And no it can't run without oil in any meaningful way on the street for more than maybe 15 minutes.. so again, no Honda Toyotas are no built so well that they run without oil.
The demos I've seen of running without oil or coolant were not your definiton, but the useless one of engine not doing anything other than running. don't run an engine without fluids - it will work in some cases but they are not normal and won't last long.
> other owners say it runs fine without coolant, oil, etc
Um, no. Go ahead dump your oil and coolant, go drive your car, and report back how "fine" it did.
(No, please don't actually do this. Although here's a guy who did, for the clicks. The Honda did impressively well, but it wasn't "fine". https://www.youtube.com/watch?v=zyejT4VPzlE)
My friend ran his 1995 Civic about 40 miles with no coolant in it. It warped the head and blew the head gasket. But I skimmed the head, put in a new gasket and got another 50k out of it before selling it. It didn't have a single problem the whole time I had it.
I had a friend who had a Honda (edit: actually, Toyota iirc) for ~15 years that didn’t know it had oil; So when they sold it and was asked how often the oil was changed, the potential buyer was met with a quizzical look. Tires and gasoline and window washer fluid was its maintenance.
I coworker of my mother some 20-25 years ago bought a new car. Drove it until it stopped and refused to go further. Called some road service who upon inspecting it announced that she had run out of gas. She was surprised, "Cars still need to be refueled??!!".
I find that a bit hard to believe. Someone in that family knew and took care of it sometimes.
The longest I've seen a used car go without an oil change was 40k miles and it was changed when it started making noise instantly on startup. That was basically 90k to 130k. Sure 0 to 40k would go a bit better.. but not 15 years of typical driving.
Between carbon blowby, gasoline dilution, oil burning at the rings/cylinder walls even if minimal, no car is making it 15 years if the person drives more than 5k miles a year IMO.
Unless they were driving very very low miles per year, they are simply incorrect. A car isn't making it over 100k miles without an oil change IMO, even a Toyota.
Similar to how this person went most of a lifetime without noticing and wondering what oil change businesses, advertisements, coupons, etc were for... They also didn't notice someone in their household or a service provider of some kind (brakes, tires, idk) changing their oil.
On older heavy equipment of low value and high difficulty servicing (think like a forklift or skid steer) it's not uncommon to replace the coolant with oil to mitigate a head gasket issue and simply drain some oil and add to the coolant on some semblance of a schedule.
One of my favorite tractors was the old Oil Pull's which were designed for oil in the radiator. (they were a gas engine, but designed to run on "tractor fuel" which is closer to diesel than gasoline - in order to work the engine had to be very hot)
It's of course possible to design engines to be oil cooled, though water-glycol tends to be preferred due to about twice the specific heat capacity, meaning smaller coolant channels, radiators, and fans are required.
I don't think it occurred to anyone in 1905 that a water/glycol mix might be good. They either used straight water with a warning to drain the engine when you shut down in cold weather so it didn't freeze, or they used oil. My 1939 tractor has instructions to start the engine and then pour water in the radiator when it is below freezing.
Not in 1905, no. I believe water-glycol mixes became widely used in the 1920'ies. But without glycol, water is an even better heat transfer agent. Shame about the freezing thing, though.
Is it specific heat that we care about, or rate of heat transfer?
Specific heat matters a bit, but if you make your coolant take twice the energy to change 1 degree, the same thing happens on the radiator side and you must release twice the heat to cool 1 degree.
Rate of heat transfer in general if probably more important.
Well, it gets really complex. Yes, specific heat matters, but as you say so does the heat transfer coefficient. And the viscosity. And is the flow laminar or turbulent? Etc.
But, turns out water is just very very good also when you take these other factors into account. Compared to oil, it has, as mentioned, much higher specific heat, it has higher heat conductivity, it has lower viscosity which means less pumping power and more likely to see turbulent flow which helps with mixing.
In the case of the oil pull tractor they needed to run the tractor much hotter than water boils - even if they had known modern antifreeze it still boils too hot. They also didn't know to make modern radiators - they usee very large radiators to make up for lack of surface area. (They also used exhaust to pull air through the radiator instead of a fan). All in all a very ingenious design - but there is good reason they don't make them like that anymore. (My 1939 is a lot more modern - and it lacks electric start)
