What is the best way to change spark plugs: on a cold or hot engine
Content
Silver electrodes are characterized by high thermal conductivity. Because of this, they last 2 times longer than conventional ignition elements. Their margin of safety is enough for 30-40 thousand kilometers or 2 years of operation.
If you do not know when to change the spark plugs on a cold or hot engine, it is easy to damage the threads. In the future, the car owner may have difficulty removing the worn part.
Replacing spark plugs: change spark plugs on a cold or hot engine
Conflicting opinions are written about how best to carry out repairs. Many car owners and car mechanics argue that the removal and installation of consumables must be carried out on a cooled motor so as not to get burned and break the thread.
In a service center, candles are usually changed on a warm engine. The drivers claim that the craftsmen are in a hurry to serve the order as quickly as they have no fans. Car mechanics explain that it is easier to remove a stuck part on a slightly warmed up car. And if repairs are carried out at too high or low temperatures, it will be problematic to remove the part. It also increases the risk of damage to the wire cap when disconnecting it from the candle.
What are the differences
In fact, you can change the consumables of the ignition system on a warm and cold engine, but in certain cases.
How to change candles with your own hands
To understand how to carry out this procedure correctly, you should remember some laws of physics. There is a concept of coefficient of thermal expansion. It shows how much an object will become larger relative to its size when heated by 1 degree.
Now we need to consider the properties of the materials of the ignition system at a temperature of 20-100 ° C:
- A standard steel candle has a coefficient of linear thermal expansion of 1,2 mm/(10m*10K).
- This parameter for the thread of an aluminum well is 2,4 mm / (10m * 10K).
This means that when heated, the cylinder head inlet becomes 2 times larger than the candle. Therefore, on a warm motor, the consumable is easier to unscrew, since the compression of the inlet is weakened. But the installation of a new part should be carried out on a cooled engine so that the tightening is along the cylinder head thread.
To avoid such situations, repairs should be carried out at a suitable motor temperature, taking into account the coefficients of thermal expansion of consumables and the thread of the well.
How to change spark plugs correctly: on a cold or hot engine
Over time, auto consumables wear out and cannot fully perform their functions. Each time you start the engine, the metal tip of the candle is erased. Gradually, this leads to an increase in the spark gap between the electrodes. As a result, the following problems arise:
- misfiring;
- incomplete ignition of the fuel mixture;
- random detonations in the cylinders and exhaust system.
Due to these actions, the load on the cylinders increases. And unburned fuel residues enter the catalyst and destroy its walls.
The driver is faced with the problem of starting the car, increased fuel consumption and loss of engine power.
Replacement time
The service life of the ignition elements depends on the following factors:
- tip material type (nickel, silver, platinum, iridium);
- the number of electrodes (the more there are, the less often misfires);
- poured fuel and oil (from a poor-quality product, the wear of a part can increase up to 30%);
- engine condition (on older units with a low compression ratio, wear is 2 times faster).
Standard candles made of copper and nickel (with 1-4 "petals") can last from 15 to 30 thousand kilometers. Since their price is small (about 200-400 rubles), it is better to change these consumables with oil every MOT. At least once a year.
Silver electrodes are characterized by high thermal conductivity. Because of this, they last 2 times longer than conventional ignition elements. Their margin of safety is enough for 30-40 thousand kilometers or 2 years of operation.
The platinum and iridium-coated tips are self-cleaning from carbon deposits and guarantee an uninterrupted spark at maximum temperatures. Thanks to this, they can work without fail up to 90 thousand kilometers (up to 5 years).
Some car owners believe that it is possible to increase the service life of consumables by 1,5-2 times. To do this, periodically perform the following actions:
- remove soot and dirt from the outside of the insulator;
- clean carbon deposits by heating the tip to 500 ° C;
- adjust the increased gap by bending the side electrode.
This way to help out the driver if he does not have a spare candle, and the car has stalled (for example, in a field). So you can "revive" the car and get to the service station. But it is not recommended to do it all the time, as the risk of engine breakdown increases.
Required temperature
When performing repairs, it is important to take into account the coefficient of thermal expansion. If the spark plug is made of steel and the well is made of aluminum, then the old part is removed on a cold engine. If it sticks, the car can be warmed up for 3-4 minutes to 50 ° C. This will loosen the compression of the well.
Engine spark plug replacement
Dismantling at too high or low temperatures is dangerous. Such an operation will break the threaded connection and damage the wire cap. The installation of a new part is carried out strictly on a cooled motor, so the contact will go exactly along the thread.
Additional recommendations
So that the candles do not fail ahead of time, it is necessary to fill the car with only high-quality fuel and oil.
In no case should you buy consumables of unknown brands (there are many fakes among them). It is better to consult with a specialist. Preference is given to multi-electrode products with iridium or platinum sputtering.
If the question arose: at what temperature is it correct to replace the candle, then it all depends on the stage of repair and the type of material of the part. If the old consumable is made of steel, then it is removed on a cooled or warm engine. The installation of new elements is done strictly on a cold engine.
