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1. GR Valve The electronic EGR valve is mounted to the underside of the intake manifold An exhaust port located at the rear of the left bank cylinder head supplies the exhaust gas to the EGR valve through a metal pipe Learn More Be Prepared You can learn all about the new 3 6L engine in the 2008 Tribeca from the 2008 New Model Update Technician Reference Booklet Module 917 Subaru P N MSA5P0804C which you can order from your local Subaru N E W Horizons Dealer The publication will also soon be available on the Subaru Technical Information System website at http techinfo subaru com The full service manual for the 2008 Tribeca is also available from your local Subaru N E W Horizons Dealer E February 2008 Number 41 l 132. Tribeca 3 6L Engine Subaru has developed a new technologically advanced 3 6L _ engine for the 2008 Tribeca This paves the way for future Subaru engines Here s the basic technical information and service tips you ll want to know A SUBARU he redesigned 2008 Subaru Tribeca is now on the road and selling like the proverbial hotcakes While the stunning new body style and interior are the first things you see it s the new engine under the bonnet you ll want to know more about It s brand new and different from the Subaru engines you ve been servicing When Subaru launched the 2006 Tribeca B9 it was powered by the same 250 hp 3 0L 6 cylinder engine found in the Outback The same engine was used in the 2007 model For the 2008 model now just named Tribeca the company developed a techno logically advanced engine that provides more power is more efficient emits lower emissions is lighter and operates on regular fuel This engine will undoubtably set the pattern for future Subaru engines The new 3 6L six designated EZ 36 pumps out 256 horsepower 6 000 rpm and 247 ft lbs of torque 4 400 rpm This raises the prevevious levels of power 250 hp 219 ft lbs found in the 3 0L This improvement was accomplished by increasing the displacement bore and stroke the use of upgraded mechanical and sophisticated electronic systems i a irm i The new 3 6L engine in the 2008 Tribeca uses cutting edge t
3. d of its basic idle setting When it advances it is rotated in the same direction as the engine operates clockwise as viewed from the front of the engine When the intake camshaft is advanced it allows more air and fuel to enter the cylinders and results in more power from the combustion The exhaust camshaft can retard up to 21 degrees behind its basic idle setting When it retards it is rotated in the opposite direction as the engine operates counter clockwise www endwrench com as viewed from the front of the engine When the exhaust camshaft is retarded it allows the expanding gases of the power stroke to push on the piston for a longer period of time resulting in better fuel efficiency By combining the precise control of both camshafts a condition is created where the intake and exhaust valves work together to create better scavenging of the cylinders reduced pumping losses and better EGR effect Doimi Lire Basiz Solid Line Advance or Retard This graph shows how the Dual Active Valve Timing System controls the intake and exhaust camshafts to advance and retard the timing Cam actuation is achieved by oil pressure delivered to the apply and release sides of actuators of the intake and exhaust sprockets through oil ports in the end of each camshaft The camshaft cap houses the OCV of each camshaft and a small oil filter is installed into the camshaft cap to filter the oil before it enters the OCV A small oi
4. echnologies for fuel efficiency increased horsepower and lower emissions Engine Specifications Here are the 3 6L basic engine specs compared to the 3 0L engine 3 6L 3 0L Bore 92mm 89 2mm Stroke gimm 80mm Displacement 3 630 cc 2 999 cc Weight 395 lbs 397 lbs Compression 10 5 1 10 7 1 Fuel AKI 87 91 3 6L Enhancements and Changes Several changes are incorporated into the new 3 6L engine Among them are The introduction of the Dual Active Valve Timing System to replace the Variable Valve Lift System A redesigned cooling system A new timing chain design that uses three chains Let s take a look at each of these innovations Dual Active Valve Timing System The Dual Active Valve Timing System controls both the intake and exhaust camshafts The intake camshaft is advanced while the exhaust camshaft is retarded This process can alter the timing to increase the torque in low to mid range engine speeds and also provides greater cylinder efficiency in higher engine rpm levels to improve fuel economy Both camshafts are operated by an Oil Charge Valve OCV that receives a duty ratio from the Engine Control Module ECM The higher the degree of duty ratio input the higher the degree of actuation 8 l The End Wrench The intake left and exhaust right Oil Charge Valves respectively control the advance and retard of the camshafts The intake camshaft can advance up to 51 degrees ahea
5. l filter in the camshaft cap strains out impurities that could cuase OCV malfunctions Note the placement of the oil filters oil charge valves OCVs and cam sensor on the camshaft cap The Dual Active Valve Timing System requires additional space in the timing chain cover to allow room for the exhaust sprocket The timing chain cover bulges out to encase the Dual Active Valve Timing System exhaust sprocket The larger shape of the valve cover and the front cam shaft cap allows installation of the exhaust Oil Charge Valve OCV and the exhaust camshaft sensor The exhaust camshaft sensor and exhaust OCV are mounted to the enlarged valve cover The 3 6L engine is designed with the inner timing chain cover incorporated on the front surface of the engine block and cylinder heads The outer timing chain cover is secured to the engine with 39 bolts and sealed with Three Bond Three different length bolts are used to secure the timing chain cover All are 6mm Allen type bolts except for one 6mm hex bolt located at the upper right side behind the crankshaft pulley February 2008 gt Number 41 l 9 The New Tribeca 3 6L Engine eee ty IE IE B IE vB j AL ME 24 fy ME 3C Ci Me od Note the position of the lone 6mm hex bolt behind the crankshaft pulley used to retain the timing chain cover Redesigned Cooling System The cooling system for the new 3 6L engine is a parallel flow type Thi
6. oid Valve Signal 3 Circuit Malfunction low Input P1497 EGR Solenoid Valve Signal 3 Circuit Malfunction high Input 12 l The End Wrench DTC Item continued P1498 EGR Solenoid Valve Signal 3 Circuit Malfunction low Input P1499 EGR Solenoid Valve Signal 3 Circuit Malfunction high Input P2090 Exhaust Camshaft Position Actuator Control Circuit Low Bank 1 P2091 Exhaust Camshaft Position Actuator Control Circuit High Bank 1 P2094 Exhaust Camshaft Position Actuator Control Circuit Low Bank 2 P2095 Exhaust Camshaft Position Actuator Control Circuit High Bank 2 Other New 3 6L Engine Systems and Components Oil Pump The lower oil pan is attached to the upper oil pan with 13 bolts and sealed with liquid gasket compound Six bolts secure the oil pump to the upper oil pan and two O rings seal the oil pump to the upper pan Cylinder head removal is required to remove the upper pan The oil pump is attached to the upper oil pan assembly Connecting Rods and Caps The connecting rod and cap are made in one piece then the cap is broken or snapped off during the finishing process This allows for a perfect fit between the two parts eliminating the need for dowel pins or other alignment devices when fitting the two parts together www endwrench com Right The EGR valve is fitted to the underside of the intake manifold Left Connecting rod cap separated from rod showing seam E
7. s design utilizes a water separation chamber in the block that allows coolant to flow to and across the cylinders and to and through the cylinder heads simultaneously This produces a more even engine coolant temperature throughout the entire engine and assists with controlling engine knock Ignition timing can remain advanced as cooler temperatures do not promote spark knock 10 l The End Wrench ng 9 i j Bi BY Ay Above The 39 bolts needed to fasten the timing chain cover to the block are shown here separator The new 3 6L Tribeca engine uses a parallel flow type of cooling system to create cooler operation which helps control engine knock The new design provides an increase in the lower end of the rpm range to improve the torque curve It decreases by 50 the difference in temperatures from one cylinder to another allowing for timing advance in the low to mid rpm range and increases torque without inducing knock New Timing Chain Design The 3 6L engine uses three timing chains A 10mm chain drives an idler from the crankshaft sprocket and two www endwrench com 8mm chains driven by the idler operate the left and right bank camshafts The 3 6L is an interference type engine Incorrect chain installation or turning of the camshafts out of synchronization will result in valve to piston contact Always follow the correct procedures when working on the timing chain components Above The crank
8. shaft gear drives the idler gear which then drives the right and left banks Left The new 3 6L engine uses three chains to operate the timing system the central crank gear and idler gear chain the right bank chain and the left bank chain February 2008 Number 41 l 11 The New Tribeca 3 6L Engine The left engine bank timing and camshaft drive system New Diagnostic Trouble Codes for 3 6L Engine New diagnostic trouble codes DTCs have been set in place for the 3 6L engine They deal directly with the operation of the Dual Active Valve Timing System and exhaust gas recirculation EGR This type of system is generically called an Active Valve Control System AVCS to the automotive engineering industry Here s a list of those new codes you ll want to know and refer to as needed DTC Item Poo14 Exhaust AVCS system 1 range performance Poo17 Crank and Cam timing B system failure Bank 1 Poo19 Crank and Cam timing B system failure Bank 2 Poo24 Exhaust AVCS system 2 range performance Po365 Camshaft Position Sensor B Circuit Bank 1 Po390 Camshaft Position Sensor B Circuit Bank 2 Po400 Exhaust Gas Recirculation Flow P1492 EGR Solenoid Valve Signal 1 Circuit Malfunction low Input P1493 EGR Solenoid Valve Signal 1 Circuit Malfunction High Input P1494 EGR Solenoid Valve Signal 2 Circuit Malfunction low Input P1495 EGR Solenoid Valve Signal 2 Circuit Malfunction High Input P1496 EGR Solen
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