Experts recommend replacing the oil every 8 and 10 thousand kilometers on diesel and gasoline engines, respectively. However, when the cap is opened, an emulsion appears on the lid of the oil filler neck. This "mayonnaise" definitely drives the drivers into shock. What to do if an emulsion has formed on the cover of the oil filler neck of a BMW or other car? Let's consider.
Causes
The presence of so-called mayonnaise can tell a lot. Often, this emulsion occurs when coolant enters the crankcase system. It happens:
- Due to breakdown of the gasket between the block and the head.
- Cracks in the head or block.
- Deformation of the cylinder head element.
- Water or coolant (antifreeze or antifreeze) gets into the cylinders, and then into the engine crankcase.
- Condensation
- Lack of crankcase ventilation. Hot gas contains a large percentage of water, which condenses at the top of the engine, and, as a result, an emulsion arises on the oil filler cap.
Determining the exact cause of the mayonnaise is quite difficult. However, 80 percent is a breakdown of the cylinder head gasket. Due to this malfunction, the antifreeze present in the cooling system is mixed in the oil channels with the lubrication system.
As a result, an emulsion appears under the cover of the oil filler neck. It is worth noting that such oil and antifreeze are no longer subject to further operation. Both components are changing to new ones. By the way, an emulsion on the cover of the oil filler neck (VAZ-2107 is no exception) may occur due to operating conditions. Often it occurs in winter and autumn at the first cold snap. This is due to the occurrence of condensate, which is formed when the temperature difference between the warmed motor and the outside air from the street. When the engine is warm, moisture vapor that has entered the lubricant evaporates and then condenses on the plug. Because of this, an emulsion is formed on the lid of the oil filler neck. "Gazelle" rarely suffers from such a "disease". However, when it is detected, urgent measures must be taken.
We check the rest of the place
In addition to the lid, mayonnaise may form on the probe. It should also be checked. Another reason is the use of bad oil, which does not provide lubricating properties at all.
There are times when the emulsion on the lid of the oil filler neck (photos of it are presented in our article) disappears by itself - at the first warming. But if the problem does not go away long enough, this is a signal indicating a breakdown in the cylinder head. It is through the gasket that these two components are mixed - oil and antifreeze.
Replacing the gasket on BMW, Skoda, VAZ, Gazelle cars
The process of dismantling the unit is the same for all engines (except for the rotary Mazda and the opposed Subaru). The block head is dismantled along with the receiver and the exhaust "spider". To perform this operation, you need to do a few steps. First, the fuel wires for feeding and draining the fuel are disconnected. Next, the negative is removed from the battery. Using a spanner wrench, the bonnet fastening bolts are removed. Next, it is necessary to dismantle the front bumper and the engine splash guard. After draining the old coolant. On VAZ, Gazelle cars and foreign cars (such as Skoda and BMW), it is poured by unscrewing the tap at the bottom of the radiator. Previously, a container is substituted under it. For passenger cars, a 5-liter canister is enough, for trucks of the Gazelle type, at least a 10-liter. After that, the ignition coils and the plug block of the valve timing sensor are dismantled.
After that, unscrew the bolts and remove the wires from two oil sensors - pressure and emergency pressure. Disconnect the pads from the temperature sensors, the coolant heating indicator. After that, the tightening of the clamp is loosened and the thermostat is taken out together with the pipes going to the expansion tank. Next, loosen the tightening of the element going to the brake vacuum check valve. Take out the block from TPS. Then remove the mass wire from the stud on the front of the receiver (usually it is blue). Next, unscrew the nut and pull out the accelerator cable. Disconnect the crankshaft speed sensor. It is fixed between the toothed rim of the pulley and shaft. Remove the block between the intake pipes of the engine. The gland is shifted from the cable of the threaded tip and the nut of the cable fastening is unscrewed. Remove the element from the bracket, which is mounted on the inlet pipe of the engine. For the best effect, you need to move it back.
The cable holder of the gas pedal (if it is a VAZ or “GAZelle” car) is unbent, and the element goes out. Also remove all wires from the generator, remove the connector block from the IAC (idle speed controller). Next, the temperature sensor pads are removed, the antifreeze supply pipe from the fitting of the heater stove is loosened. Now we got to the intake system. We take out the connector blocks from the four nozzles, unscrew the wiring harnesses from the holders and take them out. The exhaust system is next in turn: the
exhaust exhaust pipe is disconnected, which goes from the exhaust manifold. The next step will be the dismantling of the generator and throttle valves.
Block dismantling
We have already done most of the work. Next, we describe the procedure for dismantling the cylinder block from the engine. To do this, you must:
- Remove camshaft. If the motor is 16-valve, 2 shafts are removed.
- The clamp tightens, the hose is removed from the throttle body.
- The thermostat assembly is removed.
- The cylinder head bolts together with the washers are unscrewed.
- The head is removed along with the gasket.
It is important
In no case do not use a screwdriver, knives and other improvised items to remove the cylinder head to remove the cylinder head. Thus, you damage the surface of the element that is adjacent to the block.
Assembly
It remains only to install a new gasket and put everything in place. Please note that before installation, it is coated with red silicone sealant. The surface of the block and head (mating parts) are thoroughly cleaned of the remnants of the old sealant, accumulated chips and grease.
Look carefully at the coincidence of the labels. If the gasket is installed upside down, the situation will only get worse. Further installation is carried out in the reverse order. After that, the cylinder head is checked: with the help of a steel ruler and probes, the flatness of the surface of the head is checked, which is adjacent to the block. To do this, you need to put a ruler along the element, and use the feelers to measure the gap between both planes. If it is at least 0.2 mm, the head must be replaced. Follow the order of tightening the bolts (crosswise). A
torque wrench is required
. At the first stage, the tightening force is 39-61 N · m. After 2 hours, the second stage is performed. The tightening force is from 130 to 140 N · m.
Final stage
And the last stage - pouring new antifreeze and oil. Now they should not intersect with each other, forming a "mayonnaise". The emulsion on the oil filler cap does not threaten you. By the way, in order to avoid the formation of an air jam during pouring antifreeze, some pauses should be adhered to. That is, to enable it to completely drain from the expansion tank through the nozzles into the radiator.
For greater efficiency, you can put the car on a slope so that the front of it is higher than the rear. Then all the available air units will gather in the expansion tank.
How to prevent the formation of "mayonnaise"?
So that the emulsion on the oil filler cap does not bother you, you need to remember one simple rule: do not warm the engine for a long time at idle. In this operating mode, the crankcase ventilation system is practically not involved.
Therefore, the formation of condensate - water. Moreover, the motor on the XX does not really warm up.
Conclusion
So, we found out for what reasons an emulsion appears on the lid of the oil filler neck. "Skoda" with you or "Gazelle" - it does not matter, since "mayonnaise" is equally dangerous for all cars. If the problem does not disappear by itself, do not close your eyes to it. Perhaps you had a breakdown of the cylinder head gasket. As you can see, you can make a replacement with your own hands, but in the absence of experience or confidence, it is better to entrust this matter to professionals.