Toyota 17101-20031 Manifold, Intake

You must both reduce fuel system pressure and detach the car's negative battery cable before you can take off the upper intake plenum on these cars. Empty the coolant into a clean jug before taking off the V-bank cover, which comes loose when you unscrew and lift out the two Allen bolts. Unplug everything from the throttle body - the electrical cords, air valves, and coolant bypasses - and move the throttle lever aside; you can leave the throttle body in place unless you need to clean or replace its gaskets. Unplug the EGR pipe where it meets the intake plenum and remove the two bolts from the intake braces at the firewall side of the rear cylinder head. Then, take out the plenum mounting hardware and lift it from the lower intake manifold. Before taking the lower intake manifold off, you need to pull out the electrical cords from all the fuel injectors and remember their connection order. Take off the air assist and heater hoses from the left end of the intake manifold, detach the fuel line from the fuel rail. Carefully unscrew and remove the eight mounting nuts or bolts holding the intake manifold to the engineblock, but be cautious to keep the two gasket surfaces from separating. We must replace the water transfer hose every time we take off the intake manifold while doing other engine work. When putting the intake manifold back on, remove all previous gasket debris and sealants from both the manifold and cylinder heads. Clean the connection parts, put on fresh gaskets, and put the manifold onto the engine, making sure the gaskets stay in place before threading on the nuts/bolts. Put the nuts/bolts on in three small steps of equal tension, then finish installing everything backward from how you took it apart. Put a new gasket in place for where the intake meets the plenum. In the end, add more coolant, start the engine, and search for fuel, vacuum, and coolant leaks.

To remove the engine cover, relieve the fuel system pressure and disconnect the cable from the negative terminal of the battery, then remove the oil filler cap, followed by the three fasteners and the clip securing the engine cover. For upper intake manifold removal, which provides access to the rear valve cover, rear cylinder head, and sensors, on 2004 and later Highlander and all Lexus models, remove the top cowl/ventilation cover, windshield wiper arms, and windshield wiper motor, then the lower cowl cover, and disconnect the PCV hose from the valve cover. For spark plug removal, disconnect the ground strap, ACIS system components, electrical connectors, and vacuum lines, labeling each connector for reassembly, then remove the throttle body mounting nuts, unbolt the upper intake manifold brace(s), and detach the upper intake manifold from the throttle body and lower intake manifold. For other procedures, disconnect the ground strap, ACIS system components, electrical connectors, vacuum lines, and coolant bypass hoses, clamping or plugging coolant hoses to prevent spillage, while the throttle body can remain attached unless cleaning or gasket service is needed. Remove the air filter housing and air intake ducts, disconnect the accelerator cable or electronic throttle control system connector, unbolt the upper intake manifold brace(s) and throttle body brace, then lift the upper intake manifold/throttle body assembly from the engine compartment. For the lower intake manifold, drain the coolant, disconnect electrical connectors from the fuel injectors, detach the fuel line, disconnect heater hoses, and remove the mounting bolts and nuts in reverse order of tightening sequence, ensuring not to pry between gasket mating surfaces. Replace the water transfer hose if the intake manifold is removed. For installation, scrape off old gasket material and sealant, clean mating surfaces, install new gaskets, position the manifold, and tighten the nuts/bolts in the correct sequence. Finally, install remaining parts in reverse order of removal, use a new gasket between the lower and upper intake manifolds, refill the cooling system, run the engine, and check for leaks.

The upper intake manifold, referred to by Toyota as the intake air surge tank, requires the disconnection of the negative battery terminal, with a warning for 2GR-FKS engines to relieve fuel system pressure beforehand. After removing the engine cover, all hoses and wiring from the throttle body should be disconnected, with coolant hoses pinched off to prevent draining the cooling system and labeled for clarity. The windshield wiper arms, motor, side seals, and plastic cowl must be removed, followed by the throttle body bracket, upper intake manifold brace, and throttle body. Disconnect all wiring and hoses from the upper intake manifold, then remove the mounting fasteners and the manifold itself, checking the gasket for damage and replacing it if necessary. Installation follows the reverse order, ensuring the mounting bolts and nuts are tightened to the specified torque in a circular pattern starting from the inner bolts. For the lower intake manifold, known as the intake manifold, first remove the upper intake manifold. If replacing the lower intake manifold, the fuel rail should be removed, although for 2GR-FE engines, it may not be necessary unless disconnecting fuel supply and return lines. On 2GR-FKS engines, the upper fuel rail must be removed before the lower intake manifold. After removing the interfering brace and engine mount brackets, unscrew the bolts to take off the lower intake manifold, discarding old gaskets and cleaning the mating surfaces thoroughly. Installation is again the reverse of removal, using new gaskets and tightening the bolts in a criss-cross pattern from the center outward to the specified torque.

To replace the upper intake manifold, start by disconnecting the cable from the negative terminal of the battery, ensuring to relieve fuel system pressure if the lower intake manifold will also be removed. If the engine remains in the vehicle, disconnect all hoses and wiring from the throttle body, pinching off coolant hoses to prevent draining the cooling system, and label them for clarity. Next, disconnect the air intake tube from the throttle body, remove the throttle body bracket and upper intake manifold brace, and disconnect all wiring and hoses from the manifold. Remove the two intake manifold mounting nuts and four bolts to take off the upper intake manifold, checking the gasket for damage; if it is in good condition, it can be reused. For the lower intake manifold, first remove the upper intake manifold, then if replacing the lower manifold, remove the fuel rail. If only replacing gaskets, disconnect the fuel supply and return lines without removing the fuel rail. Remove the interfering brace and the ten lower intake manifold bolts to detach the lower intake manifold. Discard the old gaskets and clean the mating surfaces thoroughly before installation, which should be done in reverse order using new gaskets and tightening the bolts in a criss-cross pattern from the center outward.