Oil in the cooling system and a burnt out heat exchanger
At many service stations that do not specialize in this
brand, and who do not know about such a "trouble", they often
sentence a car to "capital". This is, at least, "removing the
cylinder head, replacing it, grinding it, replacing the accompanying gaskets.
Such repairs cost a pretty penny to the owner, but disappointment intensifies
when the problem persists after such repairs. Therefore, do not rush, perhaps
the reason lies in the burnt out heat exchanger... It attaches to the side of
the motor and is not easy to reach. The heat exchanger is a kind of radiator
for the engine oil system. To know more, check out: oil in coolant reservoir
It is usually not large in size and has 2 circuits,
the 1st is the circuit through which the oil flows, and the 2nd circuit, in
which the coolant. The oil pressure in the engine is greater than in the
cooling system, therefore, when the heat exchanger wall burns out, the oil is
pushed out by pressure into the antifreeze circuit. Further, the oil floats in
the coolant expansion tank, which is very frightening for car owners.
It happens that the reason for the appearance of oil in the
antifreeze is a gasket that is installed between the heat exchanger and the
cylinder block.
On the surface of the heat exchanger, on the reverse side,
grooves even form, and oil under pressure penetrates into the coolant. A
similar gasket is installed on the oil cup in Bavarian engines. These heat
exchanger gaskets are commercially available, so it makes sense to replace them
first.
The manufacturer recommends draining the engine oil from the
engine before removing it, but from practice, if everything is done carefully,
then very little oil is poured out, and antifreeze does not enter the oil
system.
Coolanthave to be drained completely. On 535d in the back of
an e60 it took 3-4 hours to replace the heat exchanger and gaskets, which are
mentioned above. Why is it better to change it to a new one? Even after
removing the heat exchanger, it is very difficult to check it. Attempts to
pressurize it and check for leaks usually do not give a result, supplying
several bars to the circuit, it seems that the leak is not found anywhere.
Probably, the leak appears only "hot", the metal expands and the
crack increases. This part is commercially available not only in the original
version, and is not so expensive when compared with the price for overhauling
the motor.
There is an option to buy on "analysis" used.
repair, but no one will give a guarantee that it is serviceable, and the cost
of replacement may exceed the cost of the purchased spare. It will be so sad to
know that after such an installation the problem will not be solved.
Such a breakdown is especially dangerous for motors in
"fives" e60, tk. there is no engine temperature indicator on the
dashboard in this model, and when a lot of oil accumulates in the cooling
system, it is easy to "boil". You can find out about overheating only
when the corresponding red "light" comes on, but it may be too late.
Therefore, it is better to check the condition of the antifreeze in the
expansion tank from time to time.
