Thermostat Cover Fastener Tightening Procedure
Whenever a thermostat cover has been removed from a Mack MP7 (US04 and US07), MP8 and MP10 engine, you must use the following procedure to reinstall the cover. The tightening procedure will prevent coolant leakage, which can occur at the thermostat cover.
The procedure applies to all thermostat cover arrangements, whether mounted on the cylinder head or mounted on the remote thermostat housing as in the case of vehicles equipped with an Allison transmission. On vehicles equipped with Allison transmissions, the cylinder head mounted thermostat cover does not contain a thermostat. The fastener tightening procedures, however, are the same. The sealing ring (Part No. 1549651) must be changed anytime the cover is removed and reinstalled.
Using the sequence shown in Figure 1, tighten the thermostat cover fastener to 28N∙m (21 lb.-ft.). Recheck each fastener, using the same sequence, to ensure the fasteners are tightened to 28N∙m (21 lb.-ft.).
Safety Recalls
- The variable valve actuation line on 147,777 Caterpillar C15 6-cylinder, 15L turbocharged, air-to-air after-cooled diesel engines of 435 to 625 hp with serial number prefixes BSX, MXS, NXS, TRB, KRA and JEP may wear against the P-clips retaining the oil line, causing an oil leak. An oil leak could result in a fire.
- The fasteners that secure the fire extinguisher container to the cab on 129 model year 2008 to 2009 Autocar ACX heavy-duty vehicles may chafe against the body of the fire extinguisher mounted under the seat. Prolonged chafing may result in a hole which will cause the extinguisher to discharge. The discharge of the fire extinguisher may affect the driver’s ability to control the vehicle, increasing the risk of a crash.
- The length of the air brake hose installed between the relay valve and quick release valve for the left rear air brake assembly on 10 model year 2008 Nissan Diesel UD3300 trucks equipped with ArvinMeritor 2-speed axles is incorrect. This incorrect hose length may increase resistance in the air supply. This increases the risk of a crash.
- Certain hydraulic brake lines on 633 model year 2005 through 2008 Daimler Trucks FS65 and FB65 school and transit buses manufactured from April 1, 2004, through September 18, 2006, equipped with MBE906 engines and Allison transmissions, may contact the transmission dipstick tube as the engine rocks. Continued contact between the brake line and the dipstick tube could abrade the brake line, cause a leak and loss of brake fluid and reduce brake performance.
- The cab mounting bracket attached to the hydraulic cylinder used to raise and lower the cab for maintenance on 3,062 model year 2001 through 2007 Condor trucks built by American LaFrance, Freightliner and Sterling may wear, leading to inadequate restraint. This would allow the cab to fall forward onto the ground during maintenance.
- The diagnostics software in the central electronic module on 12,303 model year 2007 through 2008 Volvo S80 and XC 70 vehicles may cause a malfunction of the windshield wiper functionality. If this condition occurs, the windshield wipers may not operate when activated or in certain cases the windshield wipers may activate when not switched on.
- The lock support tube that may have been installed on 7,429 model year 1999 to 2009 Wilson gooseneck trailers may be beyond specification. If this is the case, the lock could develop inadequate pin engagement resulting in the gate opening unexpectedly. Check the gap between the keeper and the support tube. If it is greater than 3⁄8 inch, it must be repaired.
Air Brake Valve Replacement
When you replace the valves in the air brake system, the new valves should have the same crack pressure as those you’re replacing, according to ArvinMeritor. Replacing a valve with one that has a higher or lower crack pressure than the original valve can result in an unbalanced system and lead to unacceptable lining and drum life.
Fully Drilled Service Replacement Frame Rails
Fully drilled service replacement frame rails now are available for the following Mack chassis: all models of GU, CTP, CT, CXU, CXP, CXN, CHU and CHN; CV and RD models built November 2003 and later; LE models with standard frames built January 2004 and later; LE models with drop frames built March 2004 and later; MR and RB models built January 2004 and later; CX and CH models built October 2003 and later; and CL and DM models built February 2004 and later.
All warrantable repairs involving replacement of the frame rail(s) require use of fully drilled frame rails provided that the vehicle was manufactured after the dates specified above, and that the wheelbase was not altered from the original “as manufactured” dimension.
It is the responsibility of the service provider to verify the wheelbase of the chassis being serviced to ensure that it was not altered. Wheelbase is measured from the centerline of the front steer axle to the centerline of the rear axle for single rear axles, or the centerline of the bogie for tandem rear suspensions.
