S-class W202 Mercedes

1993-2000 of release

Repair and car operation



W202 Mercedes
+ 1.2. General information
+ 2. Maintenance
+ 3. Engines
+ 4. Greasing system
- 5. Cooling system
   + 5.2. Cooling liquid
   5.3. Antifreeze for a radiator
   5.4. A temperature regulator cooling liquids (thermostat)
   5.5. Check of system of cooling
   5.6. Hydraulic coupling of the fan
   5.7. Pump of system of liquid cooling
   5.8. Radiator
   5.9. Fan casing
   5.10. Diagnostics of malfunctions of system of cooling
   5.11. Diagnostics of malfunctions of system of indication of level of liquid
   5.12. Engine overheat
+ 6. Heating, ventilation
+ 7. Ignition system
+ 8. Fuel system
+ 9. Transmission
+ 10. Running gear
+ 11. Steering
+ 12. Brake system
+ 13. Body
+ 14. Electric equipment
+ 14.2. Electroschemes


b47c026d b47c026d

5.12. Engine overheat

GENERAL INFORMATION

Many drivers face need of expensive repair though it could be avoided, having in due time paid attention to the first signs of approaching breakage. The most characteristic example of similar refusal is break of the gear belt which timely replacement hardly is more expensive of $100, and here elimination of consequences of its break – $800–3000.

Some owners who in time have guessed "agonal rattles" car, aspire to sell it as soon as possible. The people who have forgotten Pushkin "become their victims, as a rule, you would not chase, the priest, low cost". As a result of such buyer if will not have an accident, during the next time after purchase it will be compelled to pay serious expensive repair.

To skilled drivers the provided information will seem to the trivial. However to the bulk of the motorists which has not passed "autouniversities", driving to "a characteristic crash" is peculiar.

How to avoid the pitiable ending? Today we will stop on possibility of an engine failure and we will talk about one of signs of such situation – an overheat. And it is not casual. Ahead hot summer. And, as practice testifies, in most cases the prime cause of failure of the engine at this time is its overheat. Insidiousness of an overheat that, as a rule, results affect far not at once, but affect always. And if not to accept urgent measures, consequences of an overheat will inevitably lead to serious refusals, and even at all to an engine exit out of operation. All this way accurately shares on four stages.

The first stage – emergence of the reasons of an overheat. As a rule, it:

 – podtekany cooling liquid with the subsequent decrease in level below the top branch pipe of a radiator and, as a result, the termination of circulation of liquid in a radiator and formation of an air stopper;
 – weakening of a belt, failure or engine of the fan, or sensor of turning on of the engine of the fan, or вискомуфты fan;
 – wrong adjustment of a corner of an advancing of ignition;
 – high degree of a nagaroobrazovaniye in the combustion chamber;
 – contamination of honeycombs of radiator.

The second stage – directly overheat. Most often it is shown at expectation in traffic jams and operation of the engine on single turns. There is it so: the driver sees that the arrow of the index of temperature starts to move towards a red zone, but believes that while this arrow did not reach it – anything terrible is not present. It is the first and main mistake.

Monitoring system of temperature of the engine very инерционна. The sensor of measurement of temperature is in a water shirt of the massive block of the cylinders having big capacity. So, temperature in the block of cylinders at emergence of a leak of cooling liquid and shift of its level it will be essential below temperature in a block head. Formation of an air stopper in a radiator and boiling up of liquid lead to that the block head practically remains without cooling. That it means, clearly to everyone. But the driver at the best, being nervous a little, it is mown on an arrow and continues to heat the engine. And further, depending on overheat degree, there come respectively the third and fourth stages.

During the third stage the engine continues to be heated. And it is good, if business comes to an end with failure of epiploons of valves. And that after all laying of a head of the block can "be covered", and the situation will smoothly pass to the fourth, finishing stage.

It is necessary to allocate it especially. After all if consequences of the previous stages of an overheat can be corrected in one way or another within average repair, the fourth stage assumes irreversible destructions:

 – an overheat and breakage of rings with teases of cylinders;
 – hit of cooling liquid in oil and, as a result, teases of necks of the crankshaft;
 – deformation of a head of the block;
 – formation of cracks in a head of the block and the block.

The statistics allows to allocate brands of cars, the most vulnerable to an overheat and a thicket of others "reaching" the fourth stage. Saab cars "are in the lead" here, and with a big separation. Their forced engines with the minimum gaps do not forgive Russian "perhaps". Our admirers of this model consider shameful to appear on a tow and will ruin the engine rather, than will ask to drag their car from a stopper to car-care center. And as soon as the stop reason – "stopper" – will resolve and the owner of Saab will press on a gas pedal that with pro-slipping to break away from other cars, the remains of the antifreeze cooled in a radiator will rush in the heated head and the block, which from similar rudeness will not find anything the best how to burst.

Engines of cars of other brands, though "are not so gentle", but also do not forgive the inattentive relation to them. Therefore to keep the personal estate and purse contents, it is necessary to remember unequivocally: the overheat never happens casual and never remains without consequences. And if you found a tendency to an overheat of the engine of your car, immediately stop operation before clarification of the reasons.