Toyota 5GR: Everything You Need To Know

Toyota has a wide array of engines made for all markets. With the diverse levels of compliance, the automakers, not only Toyota, needed to adapt their techniques depending on the receiving end of their product. With that being said, they released an engine exclusive for the Chinese market, the 5GR engine.

So, let us discuss the 5GR engine’s design, applications, power, tuning potential, issues, reliability, and many more.

What is Toyota 5GR Engine?

Toyota 5GR engine is the 2.5 Liter version of the GR family of engines. This version features a Dual Variable Valve Timing (VVT-i) on both camshafts but does not include direct injection but, instead, a multi-point fuel injection. 5GR engines are only built in China for vehicles specifically for the Chinese market. It shares the same engine design, architecture, and bore measurement as the 3GR-FE engine, which is also built in China to lower production costs and hold them on the same production line.

5GR engine is a member of the 8-piece family of GR engines.

Engine Specification and Design:

  • Production Run: 2005 – Present
  • Cylinder Bore Material: Aluminum
  • Cylinder Head Material: Aluminum
  • Configuration: V6
  • Bore: 87.5 mm
  • Stroke: 69.2 mm
  • Valvetrain: DOHC with four valves per cylinder
  • Displacement: 2.5 L (2497 cc)
  • Compression Ratio: 10
  • Weight: 380 lbs.
  • Max HP: 194 HP at 6,200 RPM
  • Max Torque: 179 lb-ft at 4,400 RPM

Toyota 5GR engines are designed for Rear-Drive longitudinal mounting, which is identical to the 3GR-FE engine, for which 3GR-FE machines are also substantially similar to the 2GR engines, perhaps with smaller displacement and a different layout. 5GR engines produce 194 HP at 6,200 RPM, 179 lb-ft of torque, and a compression ratio of 10.0.

Toyota 5GR-FE’s cylinder block is made from a lightweight cast Aluminum alloy. Within the bores are spiny type cast-iron cylinder liners made into the block. This surface creates an irregular texture to allow a better adhesiveness between the Aluminum cylinder block and the liners.

The 5GR engine has a bore of 87.5 mm and a shorter stroke compared to its identical counterpart, 3GR, of 69.2 mm. The banks of the cylinder have a 60-degree in V arrangement, which are then spaced in an equal offset of 36.6 mm. The external walls of the engine block were curved and used reinforced ribs to couple it to the transmission. Furthermore, spacers in the water jacket or drilled passages are installed to allow a more intensive coolant circulation near the top mount of the cylinder. This passage improves thermal efficiency and heat dissipation.

5GR engines are also equipped with an Electronic Throttle Control System or ETCS-i, which allows the electronic control module to facilitate the opening and closing of the throttle valve, which is determined through the driver’s demand via an accelerator pedal. Simultaneously, it is also responsible for positioning the throttle valve under different driving conditions and RPM range to present optimum throttle performance. It supports the SNOW operation mode, a damping response to the pressing of the accelerator pedal.

The engine’s oil filter is installed horizontally, right at the front, on top of the upper sump bracket; the front engine mount is liquid-filled, and active braces are not applied. Toyota also added an ATF warmer or heater in the cooling system, mounted on the throttle valve body cover. That significantly reduces the oil viscosity friction by raising the oil temperature under cold weather conditions, resulting in better fuel efficiency and preventing the transaxle oil from overheating while the vehicle is running.

The engine’s fuel system has a return line, and the fuel pressure regulator is built on the fuel pump module that is run by the ACIS system that operates under the same exact algorithm of those 3GRs.

The Toyota 5GR engines have Aluminum cylinder heads and dual overhead camshafts with a variable valve timing system (VVT-i) on both the intake and exhaust camshafts. These alloyed cast-iron camshafts have induction-hardened cams that were divided at the cam journals. They received a minor revision using two-layer metal-type head gaskets and shims around the bores for better durability and sealing. To add to that, it uses variable-length intake manifold ACIS (Acoustic Control Induction System) technology.

Moreover, the engine is equipped with a forged steel crankshaft made from cast iron with four journals and five balance weights; its bearings are made from aluminum. The crankshaft bearing caps are tightened from the bottom with four bolts through the plastic region tightening method.

5GR’s connecting rods are made of sintered forged steel and have narrow connecting rod bearings to reduce friction. The bigger end of the connecting rod has a 56 mm inner diameter, while the smaller end of the rod has an inner diameter of 22 mm.

Along with that, 5GR uses hyper eutectic Aluminum material for its pistons instead of the traditional forged ones that are to tighten the piston skirt clearances and added strength. This kind of composition also improves the resistance to scuffs and seizures, primarily operated at lower temperatures. It has streak-finished plastic-coated shorter skirts for seizure resistance. Oil jets are installed Into the engine block to spray onto the cylinders to reduce friction between the cylinder walls and pistons; it also improves the durability due to better lubrication.

Applications of the 5GR Engine:

  • 2005 Toyota Reiz (GRX122) (China only)
  • 2005 Toyota Crown (GRS188) (China only)

Engine Tuning, Upgrades, and Modifications

Like the presumed 3GR engines, 5GR engines are designed for city driving, weekend getaway with your family or with your friends, other errand kinds of stuff, and daily commutes, so it is not bound for any performance type of build. But if you want to achieve and work any upgrades on this engine, you have to understand that it takes serious bucks for that to happen.

If you want to continue doing it, you can start by buying performance parts such as a performance exhaust systems and a cold air intake; this can give the engine a power increase but not that enormous and may lack some. With that said, you can install a supercharger kit on the internals like the TOMS 3GR. This can deliver more than 300 HP and a slight increase in torque of 288 lb-ft. After that, buy a 3-inch performance exhaust system and get more power.

Problems Surrounding 5GR Engines:

Toyota 5GR engines, as we mentioned earlier, are similar to those of 3GR machines; therefore, most of the issues and problems that the 3GR experience may also appear in the 5GR engine. In this part, we will cover some too common problems for this engine and note that this does not happen on all but only to a small portion of the produced engines. Here is a precautionary heads up for you to use as a basis if you want or already own a 5GR engine.

The first and most common problem is the oil leak. An oil leak in the engine happens when the rubber section of the oil tube in the VVT-i lubrication system started to break or already has. This breakage is the frontrunner and leading cause of rapid oil loss in the engine resulting in oil starvation that can escalate to more severe engine damage, especially on the camshaft beds and crankshaft bearings. However, oil loss can be determined when the oil pressure warning indicator lights up, or there is some smoke coming from the engine, and you can smell burnt oil. Back to many years ago, this issue blows out of proportion on the3GR machine that Toyota even announced a recall service campaign to retrieve those faulty engines.

Another yet weak point of this engine is the leak in the water pump and noise. Water pumps are standard maintenance items and have a consumable service life of around 30,000 miles. Water pumps are essential for engine operation as it provides the coolant circulation needed for the engine. Problems such as this are threatening as faulty water pumps restrict the proper coolant flow that, if not addressed quickly, will create a resounding effect that results in engine overheating. Again, normal wear and tear is the primary culprit of this.

There are also reports that there is noise coming from the head cover area when starting the engine, and the possible errors are related to valve timing. This issue affected not only 5GR engines but also 1GR, 2GR, and 3GR engines. The root of this problem is the VVT-i sprocket. Hence, it is recommended to replace valvetrain components of the sprockets with the camshafts and carriers assembly.

Some other issues include idle speed control problems that you can solve by replacing the throttle body assembly or cleaning it—bad errors due to poor valve maintenance.

Toyota also raised major recall campaigns and raised concerns regarding valve springs. This issue is due to the foreign matter in the material or spring ruptures; corrosion of Aluminum components of the fuel system leads to the destruction of cracks, welding, and excessive fuel leaks; spontaneous loosening of the fuel pressure sensor; and defects of injector ring seals.

Summary

Toyota 5GR engines are excellent city driving and commute engine that gives the right amount of power on each application. It has the technology needed for a satisfying experience like the dual VVT-i system, ATF controls, and other minor updates.

Though its appeal is only shown in the Chinese markets, we can get a glimpse of this through the 3GR engines. This rear-wheel-drive motor can serve you for many years with proper maintenance and care. And yes, it has some shortcomings and issues, such as the water pump, VVT-i oil tube, but that does not describe the overall capability of the 5GR. Overall, this engine is reliable and solid, just like its twin brother 3GR.

I hope that this simple discussion helped you understand the 5GR engine’s design, characteristics, tuning potential, applications, issues, and overall impact on the automotive industry and community.

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