Chrysler RAM TRUCK 2500 1994 Service Manual page 264

COOLING SYSTEM DIAGNOSIS (ALL EXCEPT DIESEL)—CONTINUED
C O N D I T I O N A N D CHECKS
DIAGNOSIS
P R E S S U R E CAP VENTS TO ATMOSPHERE A N D
C O O L A N T R E S E R V E T A N K . TEMPERATURE G A U G E
R E A D I N G A B O V E N O R M A L BUT N O T H I G H :
(1) Test r a d i a t o r pressure c a p relief pressure. Refer t o Radiator
Pressure c a p section in this g r o u p .
(1) Replace c a p if relief pressure is lower than 14 psi.
C O O L A N T LOSS V I S I B L E O N G R O U N D B E L O W
V E H I C L E , BUT N O P R E S S U R E C A P B L O W O F F :
(1) Inspect system for leaks.
(1) Repair as necessary
C O O L A N T L O S S PAST P R E S S U R E C A P TOP S E A L ,
V I S I B L E O N R A D I A T O R FILLER N E C K :
(1) W i t h n o r m a l g a u g e r e a d i n g .
(2) W i t h high o r l o w g a u g e r e a d i n g o n new vehicle.
(1) a — Pressure c a p not installed tightly,
b —Pressure c a p t o p seal leaks.
c — Pressure c a p d i a p h r a g m b o w e d .
d — D a m a g e d r a d i a t o r filler neck.
e — Pressure c a p t o p seal out o f p o s i t i o n .
(2) a — Kinked coolant reserve/overflow system hose.
b — C o o l a n t reserve system tank plastic tube p l u g g e d ,
c — Pressure c a p seal out o f p o s i t i o n .
D E T O N A T I O N O R P R E I G N I T I O N . N O T C A U S E D B Y
I G N I T I O N O R E N G I N E C O N D I T I O N S :
(1) Check engine coolant freeze point. If the tester does not
register a r e a d i n g o r if the r e a d i n g is b e l o w 5 0 ° F, inspect
ethylene-glycol/water ratio. A 1 0 0 percent solution o f
ethylene-glycol in the system causes the engine t o run hotter
a n a possibly overheat.
(1) a — A d j u s t c o o l a n t solution t o 5 0 / 5 0 w a t e r ethylene-glycol
mixture.
b — I f 100 percent ethylene-glycol solution is f o u n d in
system, clean a n a flush system before r e p l a c i n g w i t h
5 0 / 5 0 mixture o f ethylene-glycol a n d water.
C O O L I N G S Y S T E M H O S E S C O L L A P S E
O N C O O L D O W N :
(1) Inspect pressure c a p vent valve.
(2) Coolant reserve tank hose p l u g g e d o r k i n k e d .
(3) Inside o f pressure c a p p l u g g e d .
(1) a — Gasket swell can prevent valve from o p e n i n g ,
b — Replace pressure cap.
(2) Repair as necessary.
(3) Clean c a p o r replace i f necessary.
C O O L I N G S Y S T E M S U S P E C T E D A S C A U S E O F
I N A D E Q U A T E A I R C O N D I T I O N I N G S Y S T E M
P E R F O R M A N C E :
(1) Inspect for p l u g g e d r a d i a t o r and/or condenser.
(2) Inspect for missing a i r seals in the recirculating a i r p a t h .
(1) Clean with l o w pressure w a t e r from fan side.
(2) Repair as necessary.
E X C E S S I V E F A N N O I S E :
(1) Inspect for loose o r bent fan blades.
(2) Inspect clearance between fan a n d adjacent p a r t .
(3) Inspect r a d i a t o r a n d condenser for incoming a i r
obstructions.
(4) Inspect thermal viscous fan drive.
(1) Replace fan.
(2) Repair o r replace as necessary.
(3) Clean a i r p a t h w i t h l o w pressure w a t e r from f a n side.
(4) Replace if viscous drive does not o p e r a t e p r o p e r l y .
HEAT O D O R :
(1) Was temperature g a u g e r e a d i n g high?
(2) A r e a l l heat shields in place?
(3) Is the a i r side o f the heat exchanger plugged?
(4) Engine running rich causing catalytic converter to overheat.
(1) If YES, refer t o G A U G E R E A D I N G H I G H . If N O , refer to
steps 2 , 3 , a n d 4 .
(2) If YES, refer t o steps 3 a n d 4 . If N O , r e p a i r as r e q u i r e d .
(3) Clean as necessary.
(4) Repair as necessary.
1
P O O R D R I V E A B I L I T Y , S U S P E C T THERMOSTAT FAILED
I N O P E N P O S I T I O N :
(1) Check O n - B o a r d Diagnostics. Is code 17 set in memory?
(1) If YES, replace thermostat. If N O , refer to the a p p r o p r i a t e
Powertrain Diagnostic Procedures m a n u a l .
J 9 4 0 7 - 6