TROUBLESHOOTING
Page 67
CHASSIS-MOUNTED CHARGE
AIR COOLING TESTS
[233 FA]
General Information
The Chassis-Mounted Charge Air Cooling
(CMCAC) system cools hot turbocharged air
before it enters the engine intake manifold. The
CMCAC system uses ambient air as a cooling
medium by allowing it to pass through a core
equipped with heat-exchanging fins.
Hot turbocharged air, varying in pressure from
0.0–25 psi (0.0–172 kPa), passes through core
tubes where heat is transferred to the ambient air
by heat-exchanging fins.
Front-section core construction consists of a
series of cold bars, cold fins and tube plates.
Side-section core construction consists of a
series of hot bars and hot fins.
Special Tool Required
r
Charge Air Cooler Pressure Fixture J 41473
CMCAC Troubleshooting
Symptom
Probable Cause
Remedy
Normal Boost — High Pyrometer
1. Core fin obstructions.
1. Clean core fins.
Low Boost — High Pyrometer
1. Restriction in ducting between air
cleaner and turbo.
1. Check for blockage and clean.
2. Dirty turbocharger.
2. Clean turbocharger.
3. Leaks in the pressurized side of the
induction system.
3. Check for and repair leaks.
4. Inlet manifold leak.
4. Check for loose or missing fittings,
plugs, and/or damaged manifold-
to-cylinder head gaskets. Replace
missing parts, and repair loose
connections.
5. Open petcock (if equipped).
5. Close petcock.
6. Core leakage.
6. Pressure-test core. Remove, repair
or replace core if test results are
not satisfactory.
Low Power
1. Restrictions in cooler.
1. Perform restriction pressure test.
Clean out restriction.
2. Restrictions in cooler inlet and
outlet tubes.
2. Disconnect and clean obstructions.
5_106_00.bk Page 67 Friday, August 4, 2000 11:17 AM
BDC for engine manuals and specs
