Testing For Air Intake System Leakage
The turbocharger on the dCi6 engines in Mack Freedom model chassis use an outlet adapter that cannot be checked for leakage by conventional methods. The following method can be used to investigate low power complaints or when performing similar diagnostic procedures:
- Disconnect the turbocharger inlet elbow from the intake air duct.
- Using the charge air cooler tester (Tool No. J 41473), insert the plug with the air fitting into the rubber inlet elbow and secure it with a suitable hose clamp. Be sure to connect the safety cable in an accessible location to prevent the plug from blowing off when the system is pressurized.
- Connect the pressure regulator and gauge assembly from the test kit to the air fitting in the plug. Then connect shop air to the regulator.
- Slowly open the air regulator to apply a maximum of 9 psi to the intake system. The engine might need to be slowly rotated to prevent overlapping valves. If it is necessary to rotate the engine, close the air regulator to block the flow of air to the intake system.
- Spray a soap and water solution on the connection for the turbocharger outlet adapter to check for leaks. Also, spray the complete intake system, from the turbocharger inlet to the intake manifold gaskets, to check for leakage at those locations.
Do Not Reuse Bolts
Caterpillar states that hold down bolts for the fuel injector should not be reused on engine models 3116, 3126B, 3208, 3306B, 3306C, 3406B, 3406C, 3406E, C-12, C-15 and C-16. If the hold down bolts are reused, damage may occur.
When you service the electronic unit injector, replace the hold down bolts. If a washer is present on the fuel injector hold-down bolt, remove the washer and do not replace it.
Improved Oil Cooler Core
Caterpillar 3126 (Serial No. 1ED1-Up), 3126B (Serial No. 6PZ1-Up and 7JZ1-Up), 3126E (Serial No. LEF1-Up) and C7 (Serial No. FML1-Up and FMM1-Up) engines contain an improved oil cooler.
Teardrop shaped spacers and cleats for the center support were added between the cooler plates in order to improve the integrity of the oil cooler. Copper plating also has been added to the spacer in order to ensure that adequate brazing occurs.
Improved Water Temperature
An improved water temperature regulator has been developed to improve the functionality of the cooling system on Caterpillar C7 (Serial No. KAL1-99999, SAP1-99999 and WAX1-50709) on-highway engines.
The improved water temperature regulator improves the heating capabilities in the cab of on-highway trucks.
It also has a reduction in the amount of zinc in the water temperature regulator, which minimizes the chance of corrosion. Corrosion can cause the water temperature regulator to crack.
If your customer is experiencing low heat in the cab, check the operation of the water temperature regulator. Replace the water temperature regulator (Part No. 115-4223) with the same part number.
The new water temperature regulator was effective on August 1, 2006, with serial number WAX50710-Up. For SAP1-Up, KAL1-Up and WAX1-50709 on-highway truck engines, replace the old water temperature regulator with the new one for improved heating capabilities and the functionality of the cooling system.
Improved Rings
An improved top ring has been released for Caterpillar C-15 (Serial No. 9NZ1-Up) and C-15 (Serial No. BXS1-Up, MXS1-Up and NXS1-Up) engines that are used in high-load applications.
The improved top piston ring is made from stronger materials. The stronger materials have a proven robustness in order to withstand fatigue from high cycles, Caterpillar says.
For the stated engines, replace the 237-0194 top piston ring with the 247-6130 top ring piston on the piston prior to assembly. High load applications include coal and logging applications with a gross vehicle weight greater than 140,000 lbs.
Revised Fan Drive Mounting Nut
Mack implemented a revised fan drive mounting nut (Part No. 190AM5) into production on CXP and CTP models equipped with the Behr electronically modulated fan drives. Tie-in dates were October 9, 2006, for CTP models and October 24, 2006, for CXP models.
When servicing a Behr fan drive on a CXP or CTP model, always use the most current mounting nut. Tightening torque specification for this mounting nut is 17 lb.-ft. to 20 lb.-ft.
Weepage Vs. Leakage
There are reports of water pump models 280-7374 Gp and 10R-3326 Gp installed on Caterpillar C15 (S/N SDP1-Up, B5R1-Up, MXS1-Up and NXS1-Up) engines leaking from the weep hole.
The water pump is designed to weep. The weep is necessary for lubrication of the seal face. The filter absorbs coolant for an increased rate of evaporation. When the filter becomes saturated with coolant, the coolant in the filter may seep to the evaporation chamber.
When the evaporation chamber is full of coolant, the coolant may be observed at the vent hole in the cup plug. When debris enters the seal face, weep may increase. The increased weep is only temporary.
A stain or moisture on the pump housing is not indicative of pump failure. The pump should only be replaced when there is pooling of the coolant on the ground.
Trailer Wiring Data
Grote released information about how to select the correct size of electrical cable. In combination vehicles, it is important that a good quality and adequately sized ground wire is provided between the two vehicles to carry the current.
Wire has a certain resistance to current flow; the smaller the wire, the greater the resistance. Also, as the amount of current (amps) increases, the resistance (ohms) increases.
For a 12v system, the following two factors should be considered:
- Voltage drop is the primary consideration in selecting the proper electrical wire size. The length of wire in a circuit is the major contributing factor to voltage drop.
- The current carrying capacity of the wire should be considered. The heavy load in an undersized wire may increase the temperature of the PVC insulation above the safe level of 180
