Cold engine start: essence and important nuances

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

With the advent of winter for the car, as well as for its owner, black days begin: ice, icy windows, frozen door and trunk locks, frozen brake pads … But the biggest problem is the cold start of the engine. Moreover, if the air temperature drops below 20 degrees below zero, then the engine starts equally badly both on domestic cars and on foreign cars.

Why the car does not start "cold"

Poor engine start "cold" is associated with a number of reasons:

1. At temperatures below -20 degrees, a fully charged battery loses from 50 to 80 percent of its charge, despite the fact that the load on it, unlike in summer, only increases in winter.
2. The increase in the load on the battery is also associated with a change in the consistency of the oil in the engine. It gets thicker in cold weather. Therefore, the starter will need more effort to turn the crankshaft, and this, in turn, will requireadditional battery power.
3. If the candles in the car have not been changed for a long time, and have a significant output, then in order for them to be able to ignite the combustible mixture, additional energy from the battery will also be needed.



4. Low temperatures lead to the fact that due to the compression of the metal, the gaps in the valve mechanism and the combustion chamber (between the pistons and cylinder walls) increase, and this leads to a decrease in compression.
5. Due to a drop in compression, oil enters the combustion chamber, which leads to increased carbon formation, which, in addition to being deposited on candles, piston heads and valves, clogs the oil filter, significantly reducing its life.

As you can see, all the reasons that make it difficult to start the engine cold are somehow connected. And each of them contributes to the fact that the car does not start.

How to prepare your car for winter operation

First of all, it is worth mentioning the fact that each cold start of the engine in terms of wear can be equated to a run of 150–200 km, and this value increases in proportion to the temperature drop, that is, the lower the temperature, the higher the degree of engine wear. Therefore, care should be taken in advance to minimize wear and tear.

To do this, even before the onset of cold weather, you should check the electrolyte density level in the battery and, if necessary, recharge the battery. Although this, of course, will not save the battery from loss of charge at sub-zero temperatures. Therefore, the best option is to do the same as the drivers of regions where the average daily winter temperature is -30 degrees do: remove the battery at night and put it in a warm room. Lost on its removal a few minutes in the morning will be more than compensated by a trouble-free engine start.

It is better to choose oil for the winter period so that it does not change its viscosity in the cold, or at least it does not thicken much. Therefore, you should read the description for the selected oil very carefully, paying special attention to the temperature range of its application.

Before winter, you should also put new candles and filters (air, fine fuel, oil). Moreover, it would be useful to carry another set of candles with you all the time, just in case.

Cold start engine

The sequence of actions when trying to start the engine in frosty weather, in principle, is universal for all cars. Slight differences may be due to differences in fuel systems. Therefore, a cold start of a VAZ, GAZ or UAZ engine is performed in the same way as on foreign cars.

So, after a long stay in the cold, you first need to "wake up" the battery. To do this, the main beam is turned on for 10-15 seconds, this will start a chemical reaction in the battery and heat up the electrolyte.

The next step is to squeeze the clutch. This will disengage the engine and transmission, thereby removing excess load from the crankshaft. This is important, because even in neutral gear, the gears of the box will becranking, and this will require additional energy from the battery.

More than 5 seconds in one attempt to turn the starter is not necessary, otherwise you can finally plant the battery or fill in the candles, and at low temperatures this is unacceptable. If the engine is in good condition, then it should start on the 2nd, 3rd attempt.

Until it starts to work steadily, the clutch pedal should not be released, otherwise the engine may stall. After letting the car run at idle for 2-3 minutes, you can start moving smoothly (without jerks and accelerations), the engine warms up faster while driving.

A few tips for a carbureted engine

There is a folk way to make it easier to start a cold engine in the morning. To do this, half a glass of gasoline is poured into the car's lubrication system in the evening, which will not allow the oil to thicken. However, this method is effective only if mineral oil is poured into the engine. It is not suitable for synthetics and semi-synthetics. And one more thing: after two glasses of gasoline in the lubrication system, the oil will have to be changed, so this method, although effective, is more suitable for emergencies.

Also, for cold start of carbureted engines, you can use ether, or, as it is also called, “quick start” (sold in car dealerships). To do this, the air filter cover is removed and ether is injected through the throttle valves directly into the carburetor, after which the filter cover is tightly closed. Ether vapors, mixed with fuel vapors, will improve its flammability. To ignite such a mixture, even a weak spark will be enough.

It will also be useful, after parking the car, to pull out the throttle actuator regulator (“suction”) to the end, thereby blocking the access of cold air to the carburetor that has not yet cooled down. This will prevent condensation from forming in it.

What to do if the battery "died"?

If the battery is still discharged, then the simplest thing in this situation is to “light it up” from another car. This will require special copper wires with fastenings to the terminals ("crocodiles"). You need to be especially careful when lighting an injection engine, it has a lot of all kinds of electronics that can fail due to a voltage drop.

You can connect batteries without stopping the engine of the donor car, the main thing is to strictly observe the polarity and sequence.

The connection begins according to the scheme from a weak battery to a charged one:

1. From the minus of the consumer to the minus of the donor.
2. From the plus of the consumer to the plus of the donor.

You need to be very careful not to confuse the plus with the minus, otherwise the battery may explode!

After connecting, you need to let the "donor" work for another 5-10 minutes at idle, so it will recharge the battery that has been drained. Then its engine should be turned off, and only after that try to start the consumer. If this is not done, then the power surge that occurred when starting the powered engine can severely damage the electronics of the “donor”.

When none of the abovehelps, it remains only to pull the car in tow or push.

How to start a car from a tow

Starting a car from a tow is not a difficult task, but it must be done correctly. To do this, the ignition is turned on, the car is put in neutral, and you can start moving. After gaining speed (40 km / h), the clutch is squeezed out and the third gear is immediately engaged (so the load on the engine will be minimal) and the clutch is smoothly released. If the engine starts, do not immediately stop, the car may stall. You need to wait until the engine starts to work steadily (the speed stops floating).

Engine RPM at cold start usually fluctuates between 900-1200 rpm, and after warming up drops to 800.

Another problem with winter car operation is when, after a cold start, a whistle is heard from under the hood, which may disappear after warming up. However, this cannot be ignored.

What can whistle under the hood after a cold start

If a whistle is heard from under the hood of the car when the engine is cold, then there may be several reasons for this:

• Drive belts. Particular attention should be paid to the alternator belt. From a weak tension, it simply slips on the shaft, hence the whistle, after warming up the whistle may disappear.



• tensioner roller, timing mechanism (over time, the whistle intensifies and becomespermanent);
• worn shafts (pump, generator).

It must be remembered that any extraneous sound under the hood is a kind of warning about some kind of malfunction, and if you cannot determine the cause of the sound on your own, then you need to contact the service station specialists, and you should not delay it. After all, “breaking down” somewhere in the middle of the road in a hard frost is a dubious pleasure.