Warm up the engine to operating temperature. The temperature of the oil is 70-80°C.
Checking work
Remove vacuum hose (50) from the carburetor.
Suck in the air from the vacuum hose by mouth, while not allowing air to pass through. Otherwise, the O-ring in the thermal delay valve (23) defective or bimetallic valve plate does not turn on. In this case, replace the valve. Other details: 27 - air tube for the thermal delay valve.
Remove the thermostatic valve.
Cool the valve, for example, under running water while sucking air through the vacuum hose located in the middle of the valve. As soon as the valve temperature drops below +20'C, the air passage should turn on. Otherwise, the bimetallic plate of the valve is defective, replace the valve.
Electrical heating test
Reinstall the thermal delay valve. Put a test hose on the middle connecting pipe of the valve.
Start the engine (assistant) and at the same time suck in air through the test hose. After a few seconds the valve should click and there should be no more air flow.
If the valve does not turn on, remove the plug (84) and with the engine running, connect a test lamp between its contacts. If the lamp lights up, then replace the thermal delay valve, otherwise check the 8 A fuse in the additional fuse box and wires with connectors according to the wiring diagram. The additional fuse box is located either on or near the relay board at the left pillar. It includes 2 fuses (second fuse 25 A). Other details!: (254) - thermal delay valve; (25) - tension screws for the starter cover (18).
Delay time check
Test condition: The temperature of the thermal delay valve is less than +20°C, the engine is cold.
Remove hose (50) from the carburetor and draw air through it. There must be air passage.
Simultaneously start the engine (assistant) and measure the stop time until the valve switches when there is no more air flow.
The measured time is the delay time. Compare this time with the control time shown in the diagram. For example: Ambient temperature +15°C, measured time about 6 seconds, therefore within the allowed range. The valve is ok with respect to the delay time. The allowable time range at -15°C is between 10 and 16 seconds.
If the valve does not turn on or the turn-on time is outside the permissible interval, then with the engine running, remove the plug of the thermal delay valve and check the voltage and ground connection on the plug with a voltmeter. To do this, connect the voltmeter to the red-black wire and ground, then connect the voltmeter to the brown wire (-) and to the positive battery terminal. If the battery voltage is displayed both times (about 12 V), then replace the thermal delay valve. Otherwise, check the 8A fuse in the auxiliary fuse box and check the electrical connections according to the diagram.