Coolant Manifold Gasket Leaks On C-10 And C-12 Engines In Peterbilt Trucks Caterpillar

Coolant Manifold Gasket Leaks On C-10 And C-12 Engines In Peterbilt Trucks

Usage:

ENGINESC-10 (2PN, 3CS, 8YS),
C-12 (1YN, 2KS, 9NS) TRUCK ENGINES IN PETERBILT TRUCKS

Problem:

Some of the above 1997, 1998 and 1999 model year trucks may exhibit external coolant leaks from the coolant manifold gasket, at the joint between the coolant manifold and cylinder head. A majority of these leaks occur at the forward joint. Side loading of the coolant manifold by a misaligned upper coolant pipe may cause these coolant leaks. The upper coolant pipe connects the coolant manifold thermostat housing to the radiator top tank. If the source of side loading to the coolant manifold is not corrected, repeat failures may occur.

NOTE: Trucks built after August 2nd, 1999 should have corrective action in place to prevent this problem.

Solution:

Repair the coolant manifold gasket using Caterpillar Service procedures. Replace the gasket with original design, no new material or design is recommended. Standard Caterpillar Warranty coverage applies to this repair.

In order to prevent repeat failures, the upper coolant pipe should be aligned properly so that no excess side loading is exerted on the coolant manifold. This may require replacement of the hose at the coolant pipe to radiator top tank connection in order to allow proper alignment. Recommended hose lengths at this connection are as follows:

Peterbilt Models 379, 378, 357 (with Radiator Mounted Top Tank) require a 5 inch hose length at the upper coolant pipe-to-radiator top tank connection.

Peterbilt Models 377, 385 (with Firewall Mounted Surge Tank) require a 7 inch hose length at the upper coolant pipe-to-radiator top tank connection.

In the event that above hose length requirements are not met, Peterbilt will provide the proper length hoses at no charge to the customer. The following Illustration and Table identify the correct Peterbilt Part Number and the proper length for each hose:

There should be no metal-to-metal contact between the upper coolant pipe and the top tank inlet tube or the coolant manifold thermostat housing. The proper gap (within the short connection hoses) at each end should be a minimum of 38.1 mm as shown in the Illustration.

Make sure that the upper coolant pipe is not installed backwards. The end with the 90 degree bend should point to the thermostat housing. The end with the 80 degree bend should point to the radiator top tank.

The above adjustment/repairs to the upper coolant pipe WILL NOT BE COVERED BY STANDARD CATERPILLAR WARRANTY and will be made AT PETERBILT'S EXPENSE. The customer has the option to have this repair completed at the nearest Peterbilt Dealer.