The oil flow is regulated depending on the temperature. In the upper filter housing there is a thermostat, to which a valve is pressed by a spring. Depending on the oil temperature, the valve opens or closes the channels through which the oil flows either to the oil radiator or to the lower filter housing. Fig. 105 and 106 show cross-sections of filters for 6- and 8-cylinder engines.
Fig. 105. Sectional view of the oil filter of a six-cylinder engine.
1 - spring,
2 - thermostat,
3 - sealing ring,
4 - cork,
5 - upper filter housing,
6 - spring,
7 - check valve,
8 - lower filter housing,
9 - filter element,
10 - elastic support,
11 - sealing ring,
12 - sealing ring,
a - oil outlet,
in - oil inlet,
c - channel in the filter housing,
d - channel in the filter housing.
Fig. 106. Sectional view of the oil filter of an eight-cylinder engine.
1 - central bolt,
2 - sealing ring,
3 - filter cover,
4 - sealing ring,
5 - oil filter housing,
6 - filter element,
7 - nipple,
8 - pipe,
9 - pressure sensor installation location,
10 - thermostat,
11 - valve,
12 - valve seat,
13 - spring support,
14 - check valve,
15 - spring,
16 - spring,
17 - lower filter element seal,
A - unrefined oil to the oil radiator,
B - unrefined oil from the oil radiator,
a - from the oil pump,
in - to the main bearings of the crankshaft,
c - drain into the oil pan.
When overhauling the engine after a run of 1000...1500 km, the filter element must be replaced. To replace the filter element, unscrew the lower filter housing. To remove the oil filter from the engine, perform the following work:
Material borrowed from an online resource MercedesMan.ru
Six-cylinder engines
Remove the intake manifold.
Unscrew the central bolt securing the lower housing and lower the filter down.
Remove the sealing ring.
Carefully clean the separable surfaces of the filter housing and cylinder block from gasket residues, preventing them from getting into the oil channels.
Install a new oil filter with a new gasket on the engine, screw in and tighten the four mounting bolts. When installing the gasket, make sure that the gasket does not block the oil channels.
Start the engine and check the filter for leaks.
Check the engine oil level and top up if necessary.
Eight-cylinder engines
Unscrew the filter cover. Disconnect the two oil drain pipes to the radiator, unscrew the fitting between the filter housing and the shock absorber.
Disconnect the plug from the oil pressure sensor.
Loosen the mounting bolts and remove the filter.
If necessary, remove the filter element.
Clean the mating surfaces of the filter housing and cylinder block from gasket residue, preventing it from getting into the oil channels.
Install a new filter element and cover with a new sealing ring. Tighten the central bolt to 30 Nm.
Install the filter with a new gasket on the engine and tighten the mounting bolts to 25 Nm.
Perform the remaining work in reverse order. Check the engine oil level and top up if necessary.