Mercedes of the S-class W202

1993-2000 of release

Repair and operation of the car

Mercedes W202
+ 1.2. General information
+ 2. Maintenance
+ 3. Engines
+ 4. Lubrication system
- 5. Cooling system
   + 5.2. Cooling liquid
   5.3. Antifreeze for a radiator
   5.4. Temperature regulator of cooling liquid (thermostat)
   5.5. Check of the cooling system
   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 the cooling system
   5.11. Diagnostics of malfunctions of system of indication of level of liquid
   5.12. Engine overheat
+ 6. Heating, ventilation
+ 7. System of ignition
+ 8. Fuel system
+ 9. Transmission
+ 10. Running gear
+ 11. Steering
+ 12. Brake system
+ 13. Body
+ 14. Electric equipment
+ 14.2. Electrical circuitries

5.12. Engine overheat


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

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

The provided information will seem to skilled drivers trivial. However driving to "a characteristic crash" is peculiar to the bulk of motorists which did not pass "autouniversities".

How to avoid the deplorable final? Today we will stop on a possibility of 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 is its overheat at this time. Insidiousness of an overheat is that, as a rule, results affect far not at once, but affect always. And if not to take urgent measures, consequences of an overheat will inevitably lead to serious refusals, and even to an engine exit out of operation. All this way accurately is divided into four stages.

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

 – dribble of 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 of either engine of the fan, or sensor of turning on of the engine of the fan, or fan viskomufta;
 – 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 begins to move towards a red zone, but believes that so far this arrow did not reach it – there is nothing terrible. It is the first and main mistake.

The control system of temperature of the engine is very inertial. The sensor of measurement of temperature is in a water shirt of the massive block of cylinders having big capacity. So, temperature in the block of cylinders at emergence of a leak of cooling liquid and shift of its level will be significantly lower than temperature in a block head. Formation of an air stopper in a radiator and boiling up of liquid is led to the fact that the block head practically remains without cooling. That it means, it is clear to everyone. But the driver at best, being nervous a little, askances at 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 laying of a head of the block can "be spread", and the situation will smoothly pass into the fourth, closing stage.

It should be allocated especially. If consequences of the previous stages of an overheat can be corrected in one way or another within average repair, then 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 another "reaching" the fourth stage. The Saab cars "are in the lead" here, and with a big separation. Their forced engines with the minimum gaps do not forgive the Russian "perhaps". Our admirers of this model consider shameful to appear on the tow and will ruin the engine rather, than will ask to drag their car from a stopper to car service. And as soon as the reason of a stop - "stopper" – will resolve and the owner of Saab will press on the accelerator 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 contents of a purse, it is worth remembering unambiguously: 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.