PB 150 V8-318 5.2L VIN T 2-BBL (1983)
Thermostatic Air Cleaner: Testing and Inspection
Heated Inlet Air System (HIAS)
EXC. 4-156 ENGINE
1.
Check that all vacuum hoses and the stove to air cleaner flexible connector are installed properly and in good condition.
2.
On carbureted engines, with engine cold and engine compartment temperature below 50° F (65° F on 4-135 engine), snorkel heat control door
should be in the up (heat on) position. On fuel injected 4-153 engines, with engine cold and engine compartment temperature below 115°F, snorkel
heat control door should be in the up (heat on) position.
3.
Start engine and allow it to reach normal operating temperature. Check air temperature entering snorkel at sensor. On carbureted engines, when air
temperature entering outer end of snorkel is above 99° F (89° F on 4-135 engine), the heat control door should be in the down (heat off) position.
On fuel injected 4-153 engines, when air temperature entering outer end of snorkel is above 140°F, the heat control door should be in the down
(heat off) position.
4.
On carbureted engines, remove air cleaner from engine and allow it to cool down to 50° F (65° F on 4-135 engine). On fuel injected 4-153
engines, remove air cleaner and allow it to cool down to 115°F.
5.
Connect a hand operated vacuum pump to sensor and apply 20 inches Hg vacuum to sensor. The heat control door should be in the up (heat on)
position. If not, check vacuum diaphragm.
6.
To check vacuum diaphragm, apply 20 inches Hg vacuum to the diaphragm, Figs. 20 and 21. Diaphragm should not lose more than 10 inches Hg
vacuum in 5 minutes. Release vacuum on the diaphragm, then gradually build vacuum and observe heat door operation. The door should not lift
off bottom of snorkel at less than 5.5 inches Hg vacuum (2 inches Hg vacuum on 4-135 and 4-153 engines), and be in full up position with no
more than 8.5 inches Hg vacuum (4 inches Hg vacuum on 4-135 and 4-153 engines).
7.
If door does not operate properly, replace the vacuum diaphragm. On 4-153 fuel injected engines, the heated air assembly must be replaced as a
unit.
8.
If vacuum diaphragm operates properly, but correct temperature is not maintained, replace sensor and repeat steps 2 and 3.
