SECTION 04: EXHAUST AND AFTERTREATMENT SYSTEM
DOB 2490-2789 | X3-45 Commuter PA1605 Maintenance Manual (Final Version – Rev.2 April 2016)
9
Before tightening the parts, make sure that
the catalytic converter lower support is well
centered with the exhaust inlet of the
catalytic converter.
While tightening the bolts, keep in mind to
respect the alignment of the parts and keep
the lower support as centered as possible
with the catalytic converter exhaust inlet.
4. DIFFUSER
ASSEMBLY
During stationary regeneration, exhaust gases
temperature may get very hot at the DPF outlet.
The diffuser decreases the exhaust gasses
temperature by about half approximately, at 6
inches above the diffuser. The diffuser is an
important component of the exhaust system and
must remain on the vehicle at all times.
Operating the vehicle without the diffuser may
seriously damage the vehicle.
FIGURE 6: DIFFUSER ASSEMBLY
04014
4.1 DIFFUSER ADJUSTMENT
Should an adjustment of the diffuser position be
necessary, first remove the exhaust
aftertreatment roof ventilation grill.
CAUTION
To prevent paint damage and fiberglass
overheating caused by hot exhaust gases, the
diffuser louvered cover must be flush with the
roof surface or may exceed the roof surface
not more than 3/32" (2mm).
CAUTION
Tighten clamps properly in order to prevent
any movement of the diffuser assembly. An
impact wrench is necessary.
1. Loosen the clamp securing the diffuser
assembly to the catalytic converter.
FIGURE 7: DIFFUSER POSITION ADJUSTMENT
04015_1
2. For proper angular position, make sure that
the two edges shown on figure 7 are parallel
with each other.
3. Using a straightedge, adjust the diffuser
assembly level. The top surface of the
warning plate fixed on the diffuser louvered
cover must be flush with the roof surface or
may exceed about 3/32".
4. Tighten the clamp securing the diffuser
assembly to the catalytic converter.
5. Reinstall the exhaust aftertreatment system
roof ventilation grill and deflector.
4.2 MAINTENANCE
At vehicle inspection intervals, inspect the
diffuser assembly as follows:
Inspect diffuser grille for stress cracking;
Check for presence of foreign matter and
debris inside the diffuser housing, remove
and clean if applicable;
Check for proper functioning of the rain cap
inside the diffuser housing, make sure that it
moves freely;
Make sure that the water drain tube is not
clogged. Pour a cup of water into the diffuser
EXHAUST
INLET
