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ENGINE COOLING
68-7
ENGINE COOLING SYSTEM COMPLAINT
TO AVOID NEEDLESS TIME AND COST IN DIAGNOSING COOLING SYSTEM COMPLAINTS, THE CUSTOMER
SHOULD BE QUESTIONED ABOUT DRIVING CONDITIONS THAT PLACE ABNORMAL LOADS ON THE COOLING
SYSTEM.
1. DOES OVERHEATING OCCUR WHILE PULLING A TRAILER?
I F ANSWER IS "YES"
-
HOW HEAVY IS TRAILER? IF TRAILER WEIGHT IS GREATER THAN 2,000 LBS. & CAR IS EQUIPPED
WlTH NORMAL DUTY COOLING SYSTEM, A HEAVY DUTY COOLING PACKAGE IS REQUIRED [PER MFR'S TRAILER HAULING
SPECS.]. FURTHER DIAGNOSTIC CHECKS SHOULD NOT BE REQUIRED.
2. IS CAR EQUIPPED WlTH ADD-ON OR AFTER MARKET AIR CONDITIONING SYSTEM?
I F ANSWER IS "YES" -WAS HEAVY DUTY RADIATOR INSTALLED WlTH THE SYSTEM? I F NO'T, INSTALL HEAVY DUTY AIR
CONDITIONING RADIATOR FOR THE CAR MODEL INVOLVED [PER MANUFACTURER'S SPECS.]. FURTHER DIAGNOSTIC
CHECKS SHOULD NOT BE REQUIRED.
3. IS OVERHEATING OCCURRING AFTER PROLONGED IDLE, IN GEAR, A/C SYSTEM OPERATING?
I F ANSWER IS "YES"
-
INSTRUCT OWNER ON DRIVING TECHNIOUES THAT WOULD AVOID OVERHEATING SUCH AS:
a.
IDLE I N NEUTRAL AS MUCH AS POSSIBLE
-
INCREASE ENGINE R.P.M. TO GET HIGHER AIR FLOW &WATER
FLOW THROUGH RADIATOR.
b. TURN A/C SYSTEM OFF DURING EXTENDED IDLES IF OVERHEATING IS INDICATED BY HOT LlGHT OR TEMP. GAGE.
FURTHER DIAGNOSTIC CHECKS SHOULD NOT BE REOUIRED.
4. IS OVERHEATING OCCURRING AFTER PROLONGED DRIVING IN SLOW CITY TRAFFIC, TRAFFIC JAMS,
PARADES, ETC.?
I F ANSWER IS "YES"
-
INSTRUCT OWNER ON DRIVING TECHNIQUES THAT WOULD AVOID OVERHEATING -SAME AS
FOR PROLONGED IDLES
-
NO. 3. FURTHER DIAGNOSTIC CHECKS SHOULD NOT BE REQUIRED.
IF NONE OF THE ABOVE APPLY, GO TO DIAGNOSTIC CHART
TO EFFECTIVELY USE THlS CHART, QUESTION THE OWNER TO DETERMINE WHICH OF THE FOLLOWING
[3] CATEGORIES APPLIES TO THE COMPLAINT:
1. HOT LlGHT OR HOT INDICATION ON TEMPERATURE GAGE
2. BOILING
3. COOLANT LOSS
1. IF COMPLAINT IS HOT LlGHT OR HOT INDICATION ON TEMPERATURE GAGE
-
WAS HOT LlGHT ACCOMPANIED BY BOILING? I F ANSWER IS "YES",
GO TO BOILING ON CHART
I F ANSWER IS "NO",
GO TO HOT LlGHT ON CHART
2. IF COMPLAINT IS BOILING
-
GO TO BOILING ON CHART
3. IF COMPLAINT IS COOLANT LOSS
-
DETERMINE I F CUSTOMER IS OVERFILLING THE SYSTEM, THlS WOULD NORMALLY RESULT I N SMALL AMOUNTS OF
COOLANT LOSS THROUGH THE OVERFLOW TUBE. I F THlS IS THE CASE, INSTRUCT THE CUSTOMER ON PROPER F I L L
LEVEL & NO FURTHER DIAGNOSTIC CHECKS SHOULD BE REQUIRED.
I F OVERFILLING IS NOT THE PROBLEM, GO TO COOLANT LOSS ON CHART
WARNING-THE COOLING SYSTEM IS DESIGNED TO OPERATE AT 15 P S I . PRESSURE & TEMPERATURES
EXCEEDING 200' F. CAUTION SHOULD BE EXCERCISED WHEN REMOVING PRESSURE CAP
OR SERVICING THE SYSTEM.
Fig. 6B-8 Cooling System Diagnosis Chart
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