Form-In-Place Gasket; Disassembly; Form-In-Place Gasket Application; Surface Preparation - Mitsubishi 4G1 Service Manual

FORM-IN-PLACE GASKET

The engine has several areas where the form-in-place gasket (FIPG) is in use. To ensure that the gasket fully
serves its purpose, it is necessary to observe some precautions when applying the gasket. Bead size,
continuity and location are of paramount importance. Too thin a bead could cause leaks. Too thick a bead, on
the other hand, could be squeezed out of location, causing blocking or narrowing of the fluid feed line. To
eliminate the possibility of leaks from a joint, therefore, it is absolutely necessary to apply the gasket evenly
without a break, while observing the correct bead size.
The FIPG used in the engine is a room temperature vulcanization (Rn/) type and is supplied in a loo-gram
tube (Part No. MD970389 or MD9971 10). Since the RTV hardens as it reacts with the moisture in the
atmospheric air, it is normally used in the metallic flange areas. The FIPG, Part No. MD970389, can be used
for sealing both engine oil and coolant, while Part No. 997110 can only be used for engine oil sealing.

Disassembly

The parts assembled with the FIPG can be easily disassembled without use of a special method. In some
cases, however, the sealant between the joined surfaces may have to be broken bylightly striking with a
mallet or similar tool. A flat gasket scraper may be lightly hammered in between the joined surfaces. In this
case, however, care must be taken to prevent damage to the joined surfaces.
Thoroughly remove all substances deposited on the gasket application surfaces, using a gasket scraper or
wire brush. Check to ensure that the surfaces to which the FIPG is to be applied is flat.' Make sure that there
are no oils, greases and foreign substances deposited on the application surfaces. Do:not forget to remove
the old sealant remaining in the bolt holes.

Form-In-Place Gasket Application

When assembling parts with the FIPG, you must observe some precautions, but the procedure is very simple
as in the case of a conventional precut gasket.
Applied FIPG bead should be of the specified size and without breaks. Also be sure toencircle the bolt hole
circumference with a completely continuous bead. The FIPG can be wiped away unless it is hardened. While
the FIPG is still moist (in less than 15 minutes), mount the parts in position. When the parts are mounted,
make sure that the gasket is applied to the required area only.
The FIPG application procedure may vary on different areas. Observe the procedure described in the text
when applying the FIPG.
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