Engine - Formed-In-Place Oil Pan Gasket
84mitsubishi01SUBJECT:
FORMED-IN-PLACE OIL PAN GASKET
NO. STB-84-09-006
DATE September 1984
MODEL 1985 Cordia/Tredia, Mirage, Truck
FORMED-IN-PLACE OIL PAN GASKET APPLICATIONS FOR 1985 MODELS
Beginning with 1985 models, formed-in-place oil pan gaskets are used on 1.5L and 1.6L Mirage engines, 1.8L and 2.0L Cordia/Tredia engines, and 2.0L Truck engines.
FIGURE 1:
OIL PAN FLANGE DESIGN CHANGED
To use the new gasketing system, the cross-section shape of the oil pan flange has been changed as shown in Figure 1.
GASKET MATERIAL
Many silicone RTV (Room Temperature Vulcanizing) products are on the market. They cure at room temperature to a rubber-like consistency, and some of them are formulated especially for use on engines equipped with oxygen sensors.
Some RTV compounds give off an odor of acetic acid (vinegar) when curing. The acetic acid vapor can destroy a car's oxygen (O(2)) sensor. If an acetic-base RTV compound is used on an engine where the acetic acid vapor can get into the exhaust system, the O(2) sensor can be permanently damaged if the engine is operated before the RTV compound has completely cured. New RTV compounds have been developed which are safe for use on O(2)-sensor-equipped engines even though the compound may not be fully cured before the engine is started.
Table I lists some of the RTV compounds that are widely available and indicates their O(2)-sensor toxicity and temperature range.
TABLE I: FORMED-IN-PLACE GASKET COMPOUNDS
REMOVAL OF OIL PAN GASKETED WITH FORMED-IN-PLACE GASKET
Oil pans gasketed with formed-in-place gaskets stick tightly. To remove the oil pan, insert a thin-bladed tool such as a scraper or putty knife between the oil pan flange and cylinder block face and tap it with a hammer to separate the two parts. Don't use a chisel or pry bar because it will bend the oil pan flange. It may be helpful to rap the drain plug smartly with a plastic mallet to release the oil pan.
SURFACE PREPARATION
When replacing a formed-in-place gasket, sufface preparation is very important. Two steps must be followed before applying the new gasket.
1. Remove all the old gasket! Scrape it off the oil pan flange and cylinder block face with a sharp scraper. If desired, an abrasive such as "3M Scotchbritte Surface Conditioning Disc" may be used, but sandpaper, sanding discs, or grinders are not recommended because they remove too much metal.
2. Clean off all oil, grease and dirt! Spray the oil pan flange and the cylinder block face with a chlorinated solvent (brake cleaner) to remove all traces of oily residue.
FIGURE 2:
APPLYING THE NEW GASKET
Apply the gasket material to the oil pan flange as shown in Fig. 2 in an even, continuous 4 mm (0.16 in) bead. Once the gasket is applied, assemble the parts not more than 10 minutes after application. Once the RTV material begins to "skin over" it will not seal properly, and leaks are likely.
Install the oil pan bolts finger-tight and then torque them evenly to not more than 6-8 N-m (50-70 in. lbs.).
STORAGE OF RTV COMPOUNDS
RTV COMPOUNDS ARE AFFECTED BY ATMOSPHERIC MOISTURE AND TEMPERATURE, THEIR SHELF LIFE EVEN IN CLOSED CONTAINERS IS A FEW MONTHS AT MOST AND LESS THAN THAT AFTER THE CONTAINER IS OPENED. STORE RTV COMPOUNDS, IN A COOL, DRY PLACE, AND DO NOT USE AN RTV COMPOUND THAT HAS BEEN STORED A LONG TIME IN AN OPENED TUBE OR CONTAINER.
ADDITIONAL INFORMATION
Read and follow the instructions furnished by the RTV compound maker. Attached to this bulletin is literature furnished by 3M Company to explain the proper use of their products. The literature is furnished as a courtesy and its inclusion does not constitute endorsement by Mitsubishi of 3M products.