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15-390000-00
HFM (intake air
temperature)Cooling fan
module
DSI 6 A/T (ATF
temperature)Coolant
temperature
sensor
Refrigerant
pressure sensor
Relay box
(12) Cooling fan control
A. Overview of cooling fan and A/C compressor
The cooling system maintains the engine temperature at an efficient level during all engine operating
conditions. The water pump draws the coolant from the radiator. The coolant then circulates through
water jackets in the engine block, the intake manifold, and the cylinder head. When the coolant reaches
the operating temperature of the thermostat, the thermostat opens. The coolant then goes back to the
radiator where it cools. The heat from automatic transmission is also cooled down through the radiator
by circulating the oil through the oil pump. ECU controls the electric cooling fans with three cooling fan
relays to improve the engine torque and air conditioning performance.
For detailed information, refer to Chapter "Air Conditioning System".
B. Components
A/C compressor
D20DTR ECU
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15-50
E. Cautions
Use only specified Engine Oil (approved by MB Sheet 229.51) for CDPF. -
Use only specified engine oil (Low Ash Oil) ▶
The vehicle equipped with CDPF should use specific engine oil to improve the engine performance
and fuel economy, and ensure the service life of CDPF. -
Issue with normal engine oil ▶
Sulfur, one of the contents of engine oil is burned and generates soot that is not regenerated by the
DPF. This remains on the filter as ashes and keeps accumulating. Eventually, this ashes will block
the filter. -
Benefit for specified engine oil ▶
Minimized the sulfur content of engine oil which reduces the service life.
Improved fuel economy and emission level of CO2 with high performance and low viscosity.
Increased service life of engine oil with high resistance to temperature. -
-
-
Problems when using unspecified engine oil ▶
The service life of filter may be reduced by 30% or more by the ashes accumulated on the filter.
The fuel economy may be reduced because of engine rolling resistance, frequent regeneration of
DPF. -
-
These problems are also caused by oil with high sulfur content, such as tax exemption oil and
heating oil, etc. *
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01-31113-01
1. DESCRIPTION AND OPERATION
1) Cleanliness and Care
An automobile engine is a combination of many machined, honed, polished and lapped surfaces with
tolerances that are measured in the ten-thousanths of an inch.
When any internal engine parts are serviced, care and cleanliness are important.
A liberal coating of enigne oil should be applied to friction areas during assembly, to protect and lubricate
the surfaces on initial operation. Proper cleaning and protection of machined surfaces and friction areas
is part of the repair procedure.
This is considered standard shop practice even if not specifically stated.
Whenever valve train components are removed for service, they should be kept in order. They should be
installed in the same locations, and with the same mating surfaces, as when they were removed.
Battery cables should be disconnected before any major work is performed on the engine. Failure to
disconnect cables may result in damage to wire harness or other electrical parts.
Page 257 of 751
01-8
Front View ▶
NO. FUNCTION NO. FUNCTION
1 HFM Sensor 12 Intake Manifold
2 Intake Air Duct 13 Cylinder Head
3 Cylinder Head Cover 14 Exhaust Manifold
4 Ignition Coi 15 Dipstick Guide Tube and Gauge
5 Spark Plug Connector 16 Connecting Rod
6 Fuel Distributor 17 Crankshaft
7 Injector 18 Engine Mounting Bracket
8 Exhaust Camshaft 19 Starter
9 Intake Camshaft 20 Crankcase
10 Valve Tappet 21 Oil Pump Sprocket
11 Intake Valve 22 Oil Pan
NO. FUNCTION NO. FUNCTION
23 Camshaft Adjuster 29 Oil Pump Drive Chain
24 Oil Filler Cap 30 Oil Strainer
25 Engine Hanger Bracket 31 Oil Pump
26 Cooling Fan and Viscous Clutch 32 Ring Gear and Flywheel of Drive Plate
27 Oil Filter 33 Piston
28 Timing Chain
Side View ▶
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01-91113-01
4. DIAGNOSTIC INFORMATION AND PROCEDURE
1) Oil Leak Diagnosis
Most fluid oil leaks are easily located and repaired by visually finding the leak and replacing or repairing
the necessary parts. On some occasions a fluid leak may be difficult to locate or repair. The following
procedures may help you in locating and repairing most leaks.
Finding the Leak ▶
Identify the fluid. Determine whether it is engine oil, automatic transmission fluid, power steering
fluid, etc.
Identify where the fluid is leaking from. -
-
After running the vehicle at normal operating temperature, park the vehicle over a large sheet
of paper.
Wait a few minutes.
You should be able to find the approximate location of the leak by the drippings on the paper. ·
·
·
Visually check around the suspected component.
Check around all the gasket mating surfaces for leaks. A mirror is useful for finding leaks in
areas that are hard to reach.
If the leak still cannot be found, it may be necessary to clean the suspected area with a
degreaser, steam or spray solvent. -
-
Clean the area well.
Dry the area.
Operate the vehicle for several miles at normal operating temperature and varying speeds.
After operating the vehicle, visually check the suspected component.
If you still cannot locate the leak, try using the powder or black light and dye method. ·
·
·
·
·
Clean the suspected area.
Apply an aerosol-type powder (such as foot powder) to the suspected area.
Operate the vehicle under normal operating conditoins.
Visually inspect the suspected component. You should be able to trace the leak path over the
white powder surface to the source. -
-
-
- Powder Method ▶
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01-10
Black Light and Dye Method ▶
A dye and light kit is available for finding leaks, Refer to the manufacturer's directions when using the kit.
Pour the specified amount of dye into the engine oil fill tube.
Operate the vehicle normal operating conditions as directed in the kit.
Direct the light toward the suspected area. The dyed fluid will appear as a yellow path leading to
the source. -
-
-
Once the origin of the leak has been pinpointed and traced back to its source, the cause of the leak must
be determined in order for it to be repaired properly.
If a gasket is replaced, but the sealing flange is bent, the new gasket will not repair the leak. The bent
flange must be repaired also. Before attempting to repair a leak, check for the following conditions and
correct them as they may cause a leak.Repairing the Leak ▶
Gaskets ▶
The fluid level/pressure is too high.
The crankcase ventilation system is malfunctioning.
The seal bore is damaged (scratched, burred or nicked).
The seal is damaged or worn.
Improper installation is evident.
There are cracks in the components.
The shaft surface is scratched, nicked or damaged.
A loose or worn bearing is causing excess seal wear. -
-
-
-
-
-
-
-
Page 262 of 751
01-131113-01
Leakage Test ▶
Warm the engine up to normal operating temperature.
Disconnect the negative battery cable.
Remove the spark plugs.
Check the coolant level by opening the coolant reservoir cap and replenish if insufficient.
Open the engine oil filler cap.
Connect the tester to air pressure line and adjust the scale of tester.
Install the connecting hose to spark plug hole.
Position the piston of No.1 cylinder at TDC by rotating the crankshaft.
Connect the connecting hose to tester and measure the leakage volume after blowing up
5 bar of compressed air. -
-
-
-
-
-
-
-
-
Measure the leakage volume in the completely opening condition of throttle valve by pulling the
acceleration cable. -
Perform the pressure test according to the firing order. -
Firing Order: 1 - 3 - 4 - 2 -
Compare the leakage pressure with the specifications. -
Page 282 of 751
05-31531-24
1. OIL CIRCULATION
1 Oil Strainer
2 Oil Pump
3 Oil Pan
4 Oil Non-Return Valve
5 Oil Filter
6 Oil Filter Bypass Valve
7 Main Oil Gallery
8 Closing Ball (φ 15 mm)
9 Crankshaft
10 Connecting Rod Bearing
11 Crankshaft Bearing
12 Connecting Rod
13 Piston
14 Oil Spray (Piston Crown Area)
15 Non-Return Valve (Crankcase)16 Oil Supply (To Chain Tensioner)
17 Camshaft
18 Cam Bearing
19 Valve
20 Oil Gallery (Supply Oil to Intake Tappet)
21 Oil Gallery (Supply Oil to Exhaust Tappet)
22 Ball (φ 8 mm)
23 Camshaft Plug
24 Seal
25 Screw Plug
26 Oil Return Gallery (Cylinder Head and Crankcase)
27 Oil Return Gallery (Crankcase)
28 End Cover (φ 20 mm)
29 Oil Return Pipe