A predicament familiar to numerous motorists when oil stains can be found in antifreeze. That is usually found when checking the coolant level in the expansion tank. It's clear that this "speaks" of some kind of malfunction in the engine systems, which we will discuss in this article. To know more, check out: oil in coolant reservoir

Reasons for the appearance of oil Most car owners realize that cooling and oil are two different independent isolated systems that operate separately from each other. When there was a mixing of these systems, it means that one of them was simply depressurized. In this instance, there's a gas leak in the engine lubrication system, which explains why the oil could enter the antifreeze and it is necessary to figure out why this happened.

There are several ways of getting oil to the cooling system and we will consider them in order:

• Cracked oil line in the cylinder block;

• Burnout of the block head gasket;

• Microcracks in the torso of the block head;

• Wear of the warmth exchanger (oil cooler) gasket;

Malfunction of the oil supply channel in the block

When a crack appears in the oil supply channel, the oil enters the engine cooling system under some pressure, causing the 2 fluids to mix.

Consequently, antifreeze loses its cooling properties, the cells of the engine cooling radiator become clogged, which could result in overheating of the ability plant and jamming of the crankshaft with the ensuing consequences.

It's very difficult to identify this kind of malfunction, since for this it is necessary to disassemble the engine completely and give the cylinder block for pressure testing, carried out on a particular stand in water under air pressure.

If the supply line is broken, air bubbles will appear at the point whereby it leaves the unit.

An identical malfunction, like, on VAZ engines, is "treated" by installing a metal tube of an appropriate diameter to the oil supply channel in the ability plant unit. The tube closes the crack in the oil supply channel, thereby restoring its tightness.

When it is extremely hard to eradicate the crack, then only the replacement of the block is required.

Burnout of the block gasket

If the integrity of the gasket between the pinnacle and the cylinder block is violated, it becomes possible for connecting the cooling and oil supply channels, which also leads to the ingress of oil to the antifreeze.

The clear answer to the issue is to restore the gasket with a fresh one with an obligatory check of the plane of the pinnacle and its grinding if necessary (required in 90% of cases).

After grinding the plane, the master indicates how big the removed metal and based on this, the right block gasket is selected.

Block head malfunctions

In cases when the engine is not equipped by having an oil separator, and oil enters the cooling system, then almost certainly the main reason is based on the block head.

To determine the reason for the malfunction, the pinnacle should be taken off the engine, disassembled and pressurized to be able to establish the leak.

This is a rather laborious and costly operation. In some cases, if it is possible to obtain near the crack, the pinnacle body is welded in an argon atmosphere. When this isn't possible, then only the replacement of the "head" is required.