How many miles does warming your car up add
Discussion
Gwagon111 said:
So how many miles does warming your car up, say for five minutes a day, add to the mileage of your car, without it registering.
Well if it is stationary whilst warming up........er none. And if it is moving forwards then.......er some, depending on your speed and distance travelled in 5 minutes. Thats assuming by warming up you mean running the engine as opposed to letting it stand in the sunshine for example.I think he has in mind five minutes at idle before moving off.
Best to drive off within say twenty seconds of starting the engine. Both engine and fuel consumption will benefit.
Warming up the engine whilst driving before using anywhere near full perfomrmance is good practice and I'm convinced that is one of the reasons why all my cars I've had from new, have been very reliable over high mileages. Once warmed fully, I often use the engine's full powerband for acceleration. It's all about balance.
The temperature guages can be misleading. Even on a cold morning, the needle on the gauge of my MG ZS ( 1.8 K-Series ) usually reaches the fully warmed midway position within a mile. No way is that all alloy little engine and its oil fully warmed. Needs minimum of five miles.
The big iron block nin my Rover 620ti takes along long time to become fully warmed. Although the Thermostat bypass allows heat into the car shortly after start up and for several miles thereafter before the thermostat opens allowing coolant to circulate fully.
A friend has a temperature sensor in the sump of his similar car. Even during a twenty mile motorway run in the recent very cold conditions, the sump oil didn't reach its normal temperature.
SECOND THOUGHTS ...
There again if you warm it up in gear with spinning wheels clear of ground, the trip and odometer will 'clock' up the miles.
Best to drive off within say twenty seconds of starting the engine. Both engine and fuel consumption will benefit.
Warming up the engine whilst driving before using anywhere near full perfomrmance is good practice and I'm convinced that is one of the reasons why all my cars I've had from new, have been very reliable over high mileages. Once warmed fully, I often use the engine's full powerband for acceleration. It's all about balance.
The temperature guages can be misleading. Even on a cold morning, the needle on the gauge of my MG ZS ( 1.8 K-Series ) usually reaches the fully warmed midway position within a mile. No way is that all alloy little engine and its oil fully warmed. Needs minimum of five miles.
The big iron block nin my Rover 620ti takes along long time to become fully warmed. Although the Thermostat bypass allows heat into the car shortly after start up and for several miles thereafter before the thermostat opens allowing coolant to circulate fully.
A friend has a temperature sensor in the sump of his similar car. Even during a twenty mile motorway run in the recent very cold conditions, the sump oil didn't reach its normal temperature.
SECOND THOUGHTS ...
There again if you warm it up in gear with spinning wheels clear of ground, the trip and odometer will 'clock' up the miles.
Edited by MGJohn on Saturday 12th February 22:19
Think the OP was referring to the equivalent amount of engine wear and tear that goes unrecorded on your drive because the wheels aren't turning to record the miles while the engine is running but then how much wear and tear does a mile add anyway?
Redlining a clap cold engine with low oil for 5 miles is far worse than cruising a fully oiled and warmed engine for 20.
By the same token, I wonder how many extra miles I've added to my speedo over the years due to wheelspin?
ETA: iphone typos
Redlining a clap cold engine with low oil for 5 miles is far worse than cruising a fully oiled and warmed engine for 20.
By the same token, I wonder how many extra miles I've added to my speedo over the years due to wheelspin?
ETA: iphone typos
Edited by stewjohnst on Saturday 12th February 22:19
I tend to set off after about a minute and drive slowly for the first five miles or so. The temp gauge is normally into the stable zone by then. I know plenty of people who leave their cars running up for ten minutes, before setting off. I'd have thought that wasn't a good idea, I also know one guy who puts his car on stands and runs it up temperature, in gear, with the wheels spinning. He's either brave or stupid, I haven't decided yet.
Looking at aero engine service intervals, which seem to be about 50 hours between oil changes, which should equate to the old 3,000 mile standard change. That would work out as 60 mph. So essentially if you leave the engine running, every minute is worth about a mile in terms of service schedule.
davepoth said:
Looking at aero engine service intervals, which seem to be about 50 hours between oil changes, which should equate to the old 3,000 mile standard change. That would work out as 60 mph. So essentially if you leave the engine running, every minute is worth about a mile in terms of service schedule.
That sounds about right 
MGJohn said:
I think he has in mind five minutes at idle before moving off.
Best to drive off within say twenty seconds of starting the engine. Both engine and fuel consumption will benefit.
Not necessarily. In the recent freezing weather I was leaving my car to idle for 5-10 minutes before driving off in order to de-ice it. Then making journeys which themselves were of similar duration - which with it having a dirty great heavy cast-iron block and a thermostat with a significant bypass hole, would be barely long enough in that weather to get the temperature gauge into its normal operating zone. (In contrast warming it up stationary gets it warm much quicker, since there is no airflow over the radiator.) Yet comparing it with doing the same journeys in conditions which don't require de-icing so I can just get in and go, despite the approximately doubled engine running time it didn't use any more fuel and if anything used less. I put this down to the inefficiency of the cold engine - using throttle when it's cold causes it to need as much fuel on that length of run as leaving it to idle and then only using throttle when it's hot and running more efficiently.Best to drive off within say twenty seconds of starting the engine. Both engine and fuel consumption will benefit.
With the thermostat closed no water flows to the radiator. So the only extra cooling the engine gets on the move is from the airflow (this is enough to keep the engine at correct temperature on the move but not at rest, as I found out to my cost one day).
Idling the engine on the "choke" (cold start enrichment for young people) does waste fuel. There is in fact a noticeable fuel saving to be had just by reversing into a car park space (meaning you don't have to reverse out) because the engine doesn't need to enrich the mixture when idling in reverse.
Idling the engine on the "choke" (cold start enrichment for young people) does waste fuel. There is in fact a noticeable fuel saving to be had just by reversing into a car park space (meaning you don't have to reverse out) because the engine doesn't need to enrich the mixture when idling in reverse.
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