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Avoiding start-up engine wear...


Start-up engine wear is the wear inside an engine that occurs after the engine has been started and before the engine reaches its highest, normal, operating temperature, which usually takes about ten minutes.  Itís widely acknowledged by automotive engineers that most engine wear occurs within this first ten minutes of driving before the engine has reached its highest, normal operating temperature.


Five minutes at idle speed provides the minimum operating temperatureÖ

Instead of driving the vehicle when the engine is still cold in this way and suffering the associated engine wear, itís much better to always warm up the vehicle while itís stationary and let it idle for at least five minutes, until at least the minimum mark on the operating temperature gauge is reached.

After the minimum operating temperature is reached, itís best to drive the vehicle only very gently, keeping the engine RPM (revolutions per minute) below 2,000 until the engine reaches its highest, normal operating temperature.  This should take about another two to three minutes.  By making a habit of warming your engine up in this way and then driving gently until the highest, normal operating temperature is reached, you avoid much of the engine wear thatís normally associated with the start-up of a cold engine.


Why warming the engine up is so important...

The whole point of warming the engine up in this way at the lowest possible speed of idle speed is to avoid the situation as much as possible where different components of the engine increase in temperature at different rates which increases the wear and tear resulting from friction between them.  The source of heat in the engine is the combustion chambers where the fuel/air mixture explodes.

Components of the engine increasing in temperature at different rates also increases the possibility of the mating surfaces on components warping and causing mechanical problems, such as a leaking cylinder head gasket.  By allowing the engine to warm up at the slowest rate possible, which is at idle speed, the risk of this happening is minimised.

In general, wear in the engine is minimised by allowing the engine to warm up at the slowest rate possible in this way.  Conversely, the harder one drives a cold engine, the greater the temperature differences between engine components becomes.  This increases the rate of wear and increases the chance of damaging the engine.


Get a second ignition key cutÖ

If necessary, you can get a second ignition vehicle key cut and obtain a steering lock so that you can leave your vehicle locked while itís idling in your driveway.  This means that you wonít have to sit in it for five minutes waiting for it to warm up in the morning.  Instead, you can use that five minutes to get ready to leave.  By locking your vehicle while it's warming up, as well as using a steering lock, you can be confident that nobody will be able to steal your vehicle while itís warming up.

You just need to make sure that you really do have a second key before locking your vehicle while itís running so that you donít lock yourself out of your vehicle and maybe even out of your home as well.  The best way to do this is to only use a second, single, loose key to warm the vehicle up, which you can keep in your wallet or purse.  You can keep your normal set of keys in your pocket, which includes your vehicle and house keys.

So before locking your vehicle while itís idling, you just need to make sure that you have your normal set of keys in your pocket so that you can unlock the vehicle when youíre ready to leave.  Otherwise, youíll have to break into your vehicle to stop it from idling indefinitely and possibly catching fire!


Ten minutes at idle speed provides the highest, normal, operating temperatureÖ

If you want to warm the engine up to its highest, normal operating temperature so that the vehicle doesnít have to be driven gently for the sake of the engine, then you can warm it up for a full ten minutes at idle speed.  However it will still be important to drive gently for a minute or two, keeping the engine RPM below 2,000, to allow the manual transmission or automatic transmission to warm up.  After that, the engine and transmission can be pressured with higher engine RPMs, in the confidence that this wonít result in excessive wear, as would be the case if the engine and transmission were still cold.


Warm up your vehicle when youíre ready to leave a parking spotÖ

If the vehicle has been parked and it was last used two hours ago, for example, then the engine will have cooled right down.  Therefore the same procedure applies.  Itís best to let the engine idle for five minutes until the minimum mark on the engine temperature gauge is reached and then only drive the vehicle gently, keeping the engine RPM below 2000 until the engine reaches its highest, normal operating temperature.


This method of warming up the engine has stood the test of timeÖ

For three years now, Iíve been using this practice of warming up a cold engine for a minimum of five minutes at idle speed and then driving gently until the highest, normal engine operating temperature is reached.  Once the highest, normal engine operating temperature is reached, I tend to push my vehicle quite hard.

In all this time, Iíve never blown a head gasket or had any other mechanical problems at all with the engine, transmission or differential.  If I drove in the demanding manner that I do but didnít take care to warm up the engine, I really doubt that my vehicle would escape damage.  Actually, Iím confident that it would be a mechanical basket-case.


Pushing a cold engine hard is just asking for troubleÖ

People who roar off in a hurry in their vehicle when the engine is cold are doing their vehicle and their cash flow a great disservice in the medium to long term.  This practice exacerbates wear in the engine and will inevitably lead to mechanical failure over time.  Itís much better to accept the time that it takes to adopt this practice of warming the vehicle up, as well as the fuel thatís consumed when the engine is idling, as necessary costs involved in minimising wear in the engine.  The time and fuel invested in this practice are minimal in comparison to the inconvenience and expense associated with the mechanical problems that arise out of being too heavy-handed with cold engines.  If you want to keep your vehicle in its best possible state, this is a foundational practice to adopt.


You can let traffic through while driving gentlyÖ

When driving the vehicle gently with the engine RPMs below 2,000, the top speed that you can achieve will only be about 40-50 km/h (25-30 mph) depending on the terrain.  Therefore itís inevitable that cars will quickly bank up behind you as a result of you going slowly.  Personally, I donít like this happening so I pull over and let the cars behind pass.  I then continue on with driving the vehicle gently, pulling over to let cars pass as necessary.

Because it only takes about two to three minutes of driving in this way until the engine reaches its highest, normal operating temperature, this is really a small price to pay for keeping the vehicle in its best possible state.  For me, this has all become something of a habit and I know that itís saving my vehicle from a lot of wear and tear.


Keep the heater turned off while warming the engine upÖ

Itís important to be aware that having the interior heater turned on while the engine is warming up will have the counter-productive effect of cooling the engine since the interior heater draws heat away from the engine.  (Itís the engine that produces the heat for the interior heater, enabling it to work.)  An engine idling while the interior heater is on will warm up much more slowly or not at all.  For this reason, the interior heater should be turned off when the vehicle is warming up.  Later, after the engine has reached its highest, normal operating temperature so that itís producing a substantial amount of heat, the interior heater can be turned on if required.


Donít idle vehicles with catalytic converters for more than 20 minutesÖ

If your vehicle has a catalytic converter, itís important not to run the engine at idle speed (ie. while the vehicle is stationery) for more than 20 minutes.  (The catalytic converter is installed about halfway along the exhaust system.  It looks like a muffler but it actually reduces emissions in the exhaust gas rather than noise.)  Under such prolonged idling of the engine, the catalytic converter may drastically overheat because of the large volume of unburnt gas flowing into it from the engine.


Let the oil circulate throughout the engine before leaving a parking spot...

When returning to a vehicle whose engine is still warm from having been driven earlier, such as 30 minutes before, itís always best to allow the engine to idle for twenty seconds after starting it and before driving away in order to allow the oil pump to circulate oil throughout the engine and build oil pressure.

Personally, Iíve been guilty of the practice of returning to my vehicle that I had switched off twenty minutes earlier, turning the engine over and immediately driving off.  But I realised that this impatient practice can exacerbate wear in the engine because some parts of the engine wonít be properly lubricated with oil immediately after starting the engine, since much of the engine oil has drained back down into the sump at the very bottom of the engine while the vehicle was parked.

When returning to the vehicle, if the engine temperature is above the minimum mark on the engine temperature gauge but still less than the highest, normal operating temperature of the engine, then the vehicle should still only be driven gently, keeping the engine RPM below 2,000, until the engine reaches its highest, normal operating temperature.



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Copyright 2016 Andrew Mackinnon.  All rights reserved.