newmercman:
There’s a simple reason I like to warm things up, the sound of the engine, when it’s cold it sounds like a washing machine full of nuts and bolts, a bit of heat in it and it sounds much smoother, I’m assuming that the metal parts haven’t changed in size as the temperature difference is minimal, but that the oil has thinned out and is cushioning the blow of metal to metal contact, which is another way of saying lubrication.
But multi-grade oils are designed to maintain their viscosity fairly consistently, not to “thin out” as they increase in temperature (or thicken out when they are cold, depending on which way around you think about it). Granted they do change viscosity slightly, but not so much as to impair lubrication at any normal temperature.
There isn’t a single point at which viscosity is just right, outside of which additional wear occurs - rather, within a certain range, any viscosity will do, the outer limit on one side being the ability of the oil to flow and penetrate into the parts under reasonable oil pressures (greases would struggle to penetrate), and the outer limit on the other side being the ability of the oil to bear the pressure exerted by the parts without being squeezed out (thin oils and solvents having almost no ability to resist displacement).
I’m led to believe cold engines tend to be a bit clattery because the temperature affects the timing and behaviour of combustion, causing noise in two ways, firstly by affecting the timing of ignition itself, and secondly because the whole engine is tighter and less efficient when cold which requires slightly more fuel to be burnt to get it to turn over against its own internal resistance (making it noisier relative to the set idle speed). And of course there are various auxiliary systems where rubber belts, pulleys, and gaskets will be a bit stiff and less accomodating, plastic covers are a little bit more rigid and resonant, bearings and shafts which are a little bit tighter than when warm, and so on, and the noise properties of the engine are of course finely tuned to be best at normal operating temperature (if it were tuned to be most quiet when cold, it would become slightly noisier when at operating temperature). None of it necessarily indicates that anything is out of order or suffering undue wear due to inadequate lubrication.
Just to add a little something to the thread, I have a Webasto engine heater fitted on my Volvo, it’s basically a night heater for the engine, it heats things up nicely, depending on ambient temperature it will bring coolant temperature up to 170deg in anything from 30mins to 2hrs.
On the CAT I have a Thermo King TriPac APU, a donkey engine that shares coolant with the big engine, it kicks it when coolant temperature reaches a certain point and keeps the batteries charged, it also has an A/C facility to avoid idling all night in summer. It cost me $13,000 but will pay for itself in extended engine life and fuel costs over the lifetime of the big engine.
A bit of a contradiction you may think, advocating idling in one breath and not in the next, but there’s idling and idling, my ears tell me that warming up before setting off is kinder to the engine, my common sense tells me that excessive idling is bad for my engines.
I’ve definitely put my money where my mouth is on this issue, it is an issue too, if it wasn’t the likes of Thermo King and Webasto would not make things that warm engines to avoid running with a cold engine.
Well to be honest, third parties will make anything that sells in the marketplace, whether they be engine heaters or santa outfits for dogs. The more pertinent question is why, if they have an appreciable effect in normal climates, do the engine manufacturers not fit them as standard (or at least push them as options that any sensible person would want to purchase)?
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In addition to all the other variables involved in applying load to an engine during the warming process.Including that question of fuel washing oil off the bores.When we know that the bores are just as cold as they are in the case of an idling engine.But an idling engine is obviously putting in a lot less fuel to do it than an engine under load is.
