E 250 Van L6-300 4.9L (1984)
Exhaust Manifold: All Technical Service Bulletins
Exhaust Manifold - Exhaust Leak
EXHAUST - 4.9L - MANIFOLD WARPS AND
LEAKS
NOISE - 4.9L - EXHAUST MANIFOLD WARPS AND LEAKS
Article No.
88-7-16
LIGHT TRUCK:
1984-86 E SERIES, F SERIES, BRONCO
WARNING:
This modification is authorized only for the listed engines. Performing this modification on other engine calibrations is unauthorized and
could create liability under applicable federal or local laws.
ISSUE:
A leak at the exhaust manifold may be caused by the exhaust manifold expanding more than normal and warping under certain operating
conditions. The expanding and warping exhaust manifold causes the manifold retaining bolts to lose their torque which results in the leaking
condition.
ACTION:
To correct this, install a new design exhaust manifold kit that contains a warp resistent exhaust manifold made out of a high silicon cast
iron and new steel hot box studs. On selected calibrations it will be necessary to install a new level EEC IV processor. Refer to the
following service procedure.
1.
Remove the air cleaner.
2.
Disconnect the accelerator cable or accelerator rod at the carburetor and remove the accelerator return spring, if equipped.
3.
Remove the kickdown rod return spring and kickdown rod bellcrank from vehicles equipped with automatic transmissions.
4.
Disconnect the fuel line at the carburetor.
5.
Label and then disconnect the vacuum lines from the carburetor and intake manifold.
6.
Disconnect the carburetor feedback solenoid wiring at the carburetor.
7.
Disconnect the electrical connector from the choke cap.
8.
Remove the carburetor.
9.
Disconnect the exhaust pipe from the exhaust manifold.
10.
Disconnect the vacuum line for the brake booster, if equipped.
11.
Remove the retaining bolts and nuts holding the intake and exhaust manifolds to the cylinder head.
12.
Lift the intake manifold and exhaust manifolds as an assembly from the vehicle.
13.
Remove the gasket from the cylinder head.
14.
Remove the nuts holding the intake manifold and exhaust manifold together.
15.
Obtain Exhaust Manifold Service Kit, E4TZ-9426-D.
16.
Clean the intake manifold, exhaust manifold and cylinder head mating surfaces.
17.
Check the manifold hot box mating surface for warping. If warped, the intake manifold must be replaced.
NOTE:
To check the manifold hot box mating surface use an intake manifold that you are sure is not warped.
