Chrysler RAM TRUCK 2500 1994 Service Manual page 260

• Idle with A/C off when temperature gauge is at
end of normal range.
• Increasing engine speed for more air flow is recom­
mended.
2, T R M L E E TOWINGs
Consult Trailer Towing section of owners manual.
Do not exceed limits.
3. A I R C O N D I T I O N I N G ; ADD-ON OR A F T E R
MARKETS
A maximum cooling package should have been or­
dered with vehicle i f add-on or after market A/C is
installed. I f not, maximum cooling system compo­
nents should be installed for model involved per
manufacturer's specifications.
4. R E C E N T SERVICE OR A C C I D E N T REPAIR:
Determine i f any recent service has been performed
on vehicle that may effect cooling system. This may
be:
• Engine adjustments (incorrect ignition timing)
• Slipping engine accessory drive belt(s)
• Brakes (possibly dragging)
• Changed parts. Incorrect water pump or pump ro­
tating i n wrong direction due to belt not correctly
routed
• Reconditioned radiator or cooling system refilling
(possibly under filled or air trapped i n system).
I f investigation reveals none of the above as a
cause for an engine overheating complaint, refer to
the following Symptom and Action chart:
SYMPTOM AND ACTION (SEE PRELIMINARY CHECKS FIRST)
SYMPTOM ACTION
Slinking E n g i n e T e m p e r a t u r e
W a r n i n g Light o r H i g h G a u g e
Indication—-
Without C o o l a n t Loss
C o o l a n t Loss
Hot Vehicle (Not Englno)
Hoot D a m a g e ,
Hot C a r p o t , S o a t
f
Hot C a t a l y t i c C o n v e r t e r ,
S m o k e , Burnt O d o r
Hot Englno
C r a c k l i n g N o i s o
Hot S m e l l
S e v e r e Local Hot Spots
C o o l a n t Color
C o o l a n t R e s e r v e l O v e r f low
Tank Lovol C h a n g o s
C o o l a n t N o t R e t u r n i n g
To R a d i a t o r
Normal during temporary operation with heavy load, towing a trailer, high
outdoor temperatures, and/or on a steep loss grade.
Improper refilling procedures can result in trapped air in the system, Subsequent
operation of the pressure cap and coolant reserve system will deaereate the
cooling system. A low coolant lmm\ will then result in the coolant reserve/overflow
tank. Ada coolant. If condition persists, refer to System Diagnosis.
Check heat shielding, exhaust system, engine emission controls, ignition timing,
engine misfiring.
A moderate amount of sound from heating metal can be expected with any
vehicle. However, a crackling sound from the thermostat housing, a hot smell
and/or severe local hot spots on an engine can indicate blockedcoolant passages,
bad casting, core sand deposits and subsequent blockage, cracked cylinder block
or head, or blown cylinder head gasket. Usually accompanied with coolant loss.
Coolant color is not necessarily an indication of adequate temperature or
corrosion protection.
Level changes are to be expected as coolant volume fluctuates with enaine
temperature. If the level in the tank is between the FULL and ADD marks at normal
engine operating temperature, the level should return to within that range after
operation at elevated temperatures.
Coolant will not return to the radiator if the radiator cap vent valve does not
function, if an air leak destroys vacuum, or if the overflow passage is blocked or
restricted. Inspect all portions of the overflow passage, pressure cap, filler neck
nipple, hose, and passages within the tank for vacuum leak only. Coolant return
failure will be evident by a low level in the radiator. Reserve/overflow tank level
should increase during neat-up.
J9407-2