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Inside Sealing Mitsubishi 3 0L SOHC Engines Who For shop owners and technicians What Tips for engine sealing repairs Where Visit www felpro only com for more information Why Learn more about the broad range of Fel Pro sealing solutions for this popular Mitsubishi Chrysler engine platform Highlights Head gasket replacement tips Eliminating chronic oil pan gasket leaks Secrets to a faster higher quality sealing repair Buying the right gasket set for the job Let s face it if you re in the business of maintaining and repairing passenger car and light truck engines then you ve worked on your fair share of Mitsubishi 3 0L power plants This popular SOHC engine was widely used in Chrysler and Mitsubishi vehicle platforms beginning in 1987 light truck and 88 pass car and can even be found in a relatively small number of early Hyundai models Chances are a majority of the Mitsubishi 3 0L engines you ve seen were installed in Chrysler applications and this bi metal unit continues to represent a great opportunity for engine repair professionals Of course being a transverse mounted V6 the Mitsubishi 3 0L doesn t make life easy for any technician attempting an in chassis sealing repair That s why it s so important to do the job right the first time by relying on the Fel Pro brand s extensive portfolio of advanced sealing technologies Common Sealing Issues Among the most commonly reported sealing issues on these engines are 1 Cylinder head gasket failure 2 Oil pan gasket leakage 3 Valve stem seal material choice 4 Rear crankshaft seal design and material selection Fel Pro Solutions 1 PermaTorque solid core cylinder head gaskets with copper wire ring combustion seals money saving head installation set 2 Problem solving PermaDryPlus oil pan gasket 3 FKM Viton positive type valve stem seals with installation aid 4 PTFE crankshaft seal A Best Seller for Mitsubishi and Chrysler Mitsubishi 3 0L SOHC Nameplate Engines in Service Chrysler 1987 2004 12 085 619 Hyundai 1990 2001 59 063 Mitsubishi 1988 2004 447 016 FPO EOM 152 www felpro only com A Look Inside the Mitsubishi 3 0L By John Gurnig Field Test Technician The Mit subishi 3 0L SOHC engine is no stranger to the Fel Pro Field Test team in Skokie Not be cause this popular engine platform experienced higher than average reli ability issues but because it was used in such a vast array of applications over a nearly 20 year span Need less to say I ve opened up more than a few of these engines and have devel oped several tricks tips to save time while performing a quality repair Here are a just a few of these best practices For even more simply write me at jgurnig federalmogul com The typical head gasket failure on these engines is on the rear bank at cylinder 5 The combi nation of heat coolant circulation issues and head movement eventu ally causes the armor to fail on the OE gasket Photo 2 Note that both banks have been known to fail so be sure to re place both head gaskets See page 3 for additional information regarding this failure mode Make sure the block drains are opened during a head gasket replace ment It s common to encounter a buildup of sediment toward the rear of the block Flush out this bad stuff with the drains open and the heads off If you re dealing with a catastrophic engine failure consider purchas ing a used upper plenum rather than trying to clean out the old one These components are difficult to disassemble very hard to clean and require an anaerobic seal Been there done that An important step follow ing head gasket replace ment is to prevent cooling system air pockets by removing the coolant temperature sensor lo cated next to the thermo stat before refilling the system Photo 3 When the coolant reaches the hole I re install the CTS add more coolant and then start the engine When you see a cloud of smoke from the tailpipe of a Mitsubishi 3 0L equipped vehicle the cause is usually a valve guide seal failure The valve guides on these en gines tend to come loose after countless thermal cycles This often displac es the valve stem seals causing oil consumption The solution is to replace the OE valve guides with aftermarket guides that feature a retaining clip See page 4 for more information on this issue The valve covers on these engines feature a two piece stamped steel design and are part of the PCV system Photo 4 The covers have an inner layer that acts as an oil baffle Make sure the baffle holes are clear if the covers appear to be clogged or feel heavier than normal due to sludge buildup replace them to ensure proper PCV operation Also plan to replace the valve cover gaskets remember these gaskets are exposed to high temperatures from the exhaust manifolds and can easily turn into crispy and ineffective parts It s easier to install the valve covers before the intake manifold Make sure to place a small dab of RTV at all four corners to get a leak free seal The OE exhaust manifold gaskets are designed for specific cylinder posi tions The Fel Pro gas kets are not so these high quality replacement gaskets can be used on either bank John Gurnig runs the Fel Pro Field Test Garage in Skokie Ill He usually can be found under a hood out on the street performing a road test or back in the Fel Pro engine dyno lab Quick Tips for Diagnosing and Repairing Common Problems John Gurnig Photo 1 Typical Mitsubishi 3 0L engine an excellent repair opportunity Photo 2 Typical failed head gasket from Mitsubishi 3 0L engine Photo 3 Remove coolant temperature sensor before refilling cooling system Photo 4 Be sure the valve cover baffle holes are clear the covers are part of the PCV system Head Gasket Repairs One of the sealing challenges that has plagued Mitsubishi s popular 3 0L engine family has been the vertical casting motion between the cylinder head and block This head lift can make short work of lesser head gaskets usually leading to failure of the combustion seal It s the job of the head gasket s combustion armor to seal pressure within each of the cylinders This critical seal can be undermined by the incessant vertical motion of the cylinder head away from the block To address this issue Fel Pro Engineers developed a specialized head gasket design based heavily on the brand s strong heritage in the high performance marketplace The Fel Pro 9112PT PermaTorque head gasket utilizes a copper wire ring stainless steel combustion seal that s robust enough to resist cracking while still conforming to the engine s comparatively lightweight cylinder heads The Fel Pro head gasket also features a solid steel core gasket body and high density composite facing material with aftermarket specific coating This coating allows for casting motion and permits easy clean up In addition Fel Pro Print O Seal sealing beads block potential leaks from all coolant passages Not All Head Gaskets Are Up to the Mitsubishi Challenge Engine Years Ft Lbs 181 SOHC 3 0L 12 Valve 1992 90 Monaco Premier 1st 44 2nd loosen all bolts 3rd 30 4th turn 180 degrees 181 SOHC 3 0L 12 Valve 1989 88 Premier 1st 44 2nd loosen all bolts 3rd 15 4th turn 104 108 degrees 5th warm engine allow to cool 6th turn 45 degrees 181 1 SOHC 3 0L 12 Valve 2000 92 exc Stealth Monaco Premier Cold 80 in three steps 181 1 SOHC 3 0L 12 Valve 1991 87 exc Stealth Monaco Premier Cold 70 in three steps 181 1 SOHC 3 0L 12 Valve 1996 93 Stealth Cold 80 in three steps 181 1 SOHC 3 0L 12 Valve 1992 91 Stealth Cold 70 in three steps 181 1 SOHC 3 0L 24 Valve 2003 01 1st 80 in three steps 2nd loosen all bolts 3rd 80 in three steps again 181 1 DOHC 3 0L 24 Valve 1996 91 Cold 80 in three steps 181 1 DOHC Turbo 3 0L 24 Valve 1996 91 Cold 90 in three steps Mitsubishi 3 0L Head Bolt Torque Specifications Gasket Replacement Tips Allow engine to cool completely before disassembly Loosen remove head bolts in reverse torque sequence Thoroughly clean mating surfaces Inspect old head gasket for signs of detonation or pre ignition Check for casting warpage distortion and surface finish 003 maximum out of flat across length 002 across width 60 90 Ra surface finish acceptable Resurface castings as needed Replace head bolts using Fel Pro set ES72859 Clean and prepare bolt holes May need to chamfer and tap threads in resurfaced block Apply coat of non hardening sealer to head bolt threads extending into cooling system Torque to manufacturer s specifications below The copper wire ring used in the Fel Pro 9112PT PermaTorque head gasket ensures excellent conformability while providing extra strength needed to resist extreme head lift Repair Tips Oil Pan Upgrade from Cork Rubber The OEM oil pan gasket on Mitsubi shi 3 0L engines features cork rubber side rails with molded rubber end seals It s not uncommon for cork rubber gaskets to wick oil however To avoid this is sue consider upgrading to the Fel Pro PermaDryPlus one piece oil pan gasket This gasket features a plastic carrier along with a molded rubber sealing surface that is easier to install and longer lasting than competing gaskets The gasket available in set OS30570T also includes multiple sealing beads load limiters and integral end seals Valve Stem Seals Avoid Low Cost Alternatives Use only quality FKM rubber positive type valve stem seals like those included in Fel Pro head and valve stem seal sets to ensure controlled lubri cation of the valve stems Using low cost seals on any engine requiring high temperature resistance is an invitation to trouble Fel Pro head and valve stem seal sets come complete with seal installation aids that should be installed over the keeper groove area of the valve PRIOR to seal installation to prevent damage to the seal Rear Main Seal Gain In creased Wear Resistance In addition to the standard one piece molded rubber rear main bearing seal cataloged for the 3 0L Fel Pro offers a premium PTFE one piece high temperature seal that is a smart choice for these engines This seal features a convoluted outer diameter to keep the seal in place within its retainer and a double lipped PTFE sealing surface PTFE seals are known for their increased resistance to high temperatures and pre mature wear Important This PTFE seal must be installed dry Only Fel Pro offers 100 application specific sealing solution components for Mitsubishi 3 0L engines Each Fel Pro gasket and seal for these applications features the best material and design for the aftermarket repair environment Mitsubishi 3 0L SOHC Parts Check Fuel System Fuel Injector O Ring Sets Fuel Pump Mounting Gaskets Throttle Body Gaskets Leak Repair Camshaft Front Seal Sets Circular Plugs EGR Mounting Sets EGR Exhaust Air Supply Gaskets Grommet Sets Intake Manifold Gasket Sets Oil Pan Gasket Sets Plenum Gasket Sets Rear Main Bearing Seal Sets Spark Plug Tube Seal Sets Timing Cover Dust Seal Sets Valve Cover Gasket Sets Premium Materials Cooling System Thermostat Gaskets Water Outlet Gaskets Water Pump Gaskets Engine Repair Conversion Gasket Sets Crankshaft Front Seal Sets Head Bolt Sets Head Gaskets Head Gasket Sets Head Installation Sets Kit Gasket Sets Long Block Gasket Sets Repair Sleeves Repair Sleeve Tool Short Block Gasket Sets Valve Stem Seal Sets Exhaust System Exhaust Flange Bolt Spring Kits Exhaust Manifold Gasket Sets Exhaust Pipe Gaskets Repair Type Repair Type Premium Materials Viton Valve Stem Seals PermaDry Oil Pan Gaskets PTFE Rear Main Seals PermaDry Valve Cover Gaskets Viton is a registered trademark of the E I DuPont Company
