G6CU Sigma Engine 3.5 GDi (Kia-Hyundai) Problems And Reliability

The Korean G6CU engine with a volume of 3497 cm3 was produced for eight years, from 1999 to 2007. Hyundai has installed this motor on Equus luxury cars, Grandeur crossovers and Terracan SUVs.

It is worth noting that Kia cars were also equipped with this engine. For example, it can be found under the hood of Kia Carnival and Kia Sorento.

Description and main features

The G6CU engine has a cast iron V6 block and an aluminum 24-valve cylinder head. Also among the features of this internal combustion engine, we should mention a liquid cooling system, a timing belt with two camshafts (they have an upper location here), injection power (direct injection), a crankshaft with 4 bearings.

The power of this motor is from 194 to 220 “horses” (depending on the modification). At the same time, some cars equipped with a G6CU engine can consume more than 17 liters of gasoline per 100 km / h in urban conditions (which, of course, is quite a lot).

tuning prospects

The power of the G6CU engine modification, which is installed on the Hyundai Terracan SUV, can be increased by chipping from the original 195 to 210 hp. And the torque will increase from 300 to 320 Nm. As part of this procedure, as a rule, tuning masters also turn off the catalyst and the EGR valve (if any).

Such measures make it possible to improve the dynamic parameters in literally all modes of using the car. In addition, in this way, it is possible to increase the comfort of operation by eliminating jerks and dips.

Plus, modules are sold on the network that are able to correct readings from the sensors of this internal combustion engine. If you believe the information on the Internet, with the help of such modules, you can also significantly increase the power performance.

Applicability of G6CU engine

  • Hyundai: Equus (1999-2005), Grandeur (2002-2005), Santa Fe (2003-2006), Terracan (2001-2007)
  • KIA: Carnival (2001-2005), Opirus (2003-2006), Sorento (2002-2006)

G6CU engine Specifications

Volume (cm3)3497
Power (hp)195-220
Torque290-315 Nm
Timing driveBelt
Environmental classEuro 3
Fuel typeGasoline AI-92
ICE featuresDOHC
Supply systemDistribution injection
hydraulic liftersYes
Cylinder blockCast iron V6
cylinder headaluminum 24v
Cylinder diameter93 mm
piston stroke85.8 mm
Compression ratio10.0
Phase regulator
Engine oil5.5 l. 5w30
Average resource200,000 km.

Disadvantages and problems of the G6CU engine

  • As in many other engines, the oil scraper rings and caps quickly wear out in the G6CU, which is why the oil begins to be consumed at a faster pace.
  • In addition, even before 70,000 km of run, hydraulic expansion joints can knock here. And only replacing them will get rid of this knock.
  • This power unit is also characterized by such a problem as floating speed. Usually they occur here due to the fault of the idle speed controller or a throttle assembly clogged with dirt.
  • It should also be added that, in general, the G6CU engines of the first years of production are considered the most problematic.

Leave a Comment