Saab’s first turbo 2.3 (B234) liter engine of its own Swedish design appeared in 1989 and debuted on the Saab 9000. It was a very reliable and survivable engine. It stayed on the assembly line until 1998 and required modernization to meet stricter environmental standards and reduce production costs.
This is the B235 engine, which is essentially a much lighter B234. The cylinder block was lightened, its mechanical strength was reduced. The pistons were lightened, which reduced their strength. Even the balancer shafts got a bump, being lightened and given narrower bearings and journals. The performance of the oil pump was also reduced a bit. That is, the mechanical reliability of such an engine has become much more modest, unlike its predecessor, tuners do not even come close to it.
The 2.3-liter engine of the last generation was produced until 2010 in three modifications: B235E (170 hp or 185 hp since 2001), B235L (220 hp) and B235R (230-260 hp). All engines of this family are equipped with Trionic T7 control unit with electronic throttle.
Mechanically, these engines are almost identical. Only the younger B235E has not heat-resistant valves. The most powerful versions (more than 220 hp, big “T” next to the engine volume) are equipped with a Mitsubishi TD04HL-15T turbine, the younger one – Garrett GT1752S.
The B235 engine was installed only on Saab 9-5, from 1998 to 2010, as well as on the Aero version of the 9-3 penultimate generation, i.e. from 1998 to 2002.
Technical specifications
| Characteristics | Value |
|---|---|
| Fine volume | 2290 cm³ |
| Power system | Distributed injection |
| Engine power | 170 – 185 hp |
| Torque | 280 Nm |
| Cylinder block | Cast iron, R4 |
| Cylinder head | Aluminum, 16 valves |
| Cylinder diameter | 90 mm |
| Piston stroke | 90 mm |
| Compression ratio | 9.3 |
| Engine features | Intercooler (Intercooler) |
| Hydrocompensators | Yes |
| Transmission timing | Chain |
| Fasor regulator | No |
| Turbocharger | Garrett GT1752S |
| Recommended oil | 0W-30, 4.0 liter |
| Fuel type | AI-95 |
| Environmental class | Euro 3/4 |
| Example service life | 230,000 km |
Causes of poor starting and unstable operation
Saab drivers joke that no 9-5, which is what the B235 engine was put on, ever starts up properly.
The reasons for poor starting can be many. We will tell you more about the throttle and ignition cassette. The sources of problems with poor starting, trojan, engine stalling on the move can be found in the camshaft position sensor, fuel pump, plugs, vacuum pump, antifreeze temperature sensor, regulator on the fuel ramp, gasoline supply valve and even in the selector of the automatic transmission.
In addition, the Trionic 7 unit uses readings from the mass airflow sensor and absolute air pressure sensor to calculate the air mass on the B235 engine. Malfunctions occur with these sensors, too, affecting engine instability and traction sags.
Crankcase gas ventilation
The consequences of engine lightening are immediate. Back in the early 2000s, B235 engines began leaking oil at the junction of the timing cover (front cover) with the block and cylinder head. As it turned out, the problem was a combination of several factors: insufficient cylinder block rigidity, increased crankcase gas pressure, and a weak timing cover sealant. The lighter engine with thinner piston rings produced more crankcase gases, which the ventilation system had no time to remove. The increased gas pressure sought a way out and found its way into the weak and slightly deformed timing cover seal.
Gases opened the way for oil: its leaks were observed at the joints of the timing cover and block, cylinder head, as well as through the crankshaft oil seal. Also because of problems with the ECG there was oil consumption and turbine death: because of the support by crankcase gases of oil drain from the cartridge, turbines drove oil into the exhaust and sometimes jammed.
Saab engineers presented several options to eliminate the problem. First, they offered a reinforced timing cover, but it was of little use. Then, in 2004, they built a more productive VKG system. A kit for rebuilding the VKG for problematic B205 and B235 engines of 199-2004 model years began to be offered in 2006. A kit (55561200) with about a dozen components including hoses, oil trap, valve, and oil filler insert is still sold today. The kit installs on engines without much difficulty.
Throttle valve
The throttle of the Saab B235 engine is electronic, and the accelerator pedal position sensor is located right in it. Therefore, a pedal cable attachment is present on the throttle assembly. An uncommon throttle malfunction comes down to wear and contamination of the resistive tracks of the choke and accelerator pedal position sensors. Sometimes disassembly and cleaning of the tracks helps.
In case of malfunction, the B235 engine throttle goes into emergency mode with mechanical control by cable, errors appear, indicating malfunctions in it. In parallel, the engine barely holds idle, reacts tightly to accelerator pedal presses, does not gain speed above average, also cruise control does not work.
Ignition Cassette
The ignition cassette of the Trionic 7 module not only controls ignition and detonation, but also acts as a camshaft position sensor – it “sees” the cycles in the cylinders by the leakage currents.
Faulty cassette is indicated by ignition skips, detonation – engine shaking and loss of power. In addition, because of a faulty cassette, the engine simply does not start. Its unexpected failure is accompanied by the smell of burning wiring.
Errors indicating the failure of the ignition cassette do not always appear.
Exhaust manifold
The B235 engine’s cast iron exhaust manifold can deform due to heat and rapid cooling. Deformation can be judged by broken studs and exhaust odor.
Balancer shafts
Balancer shafts on inline fours are used to balance the second-order forces of inertia. The B235 engine has two balancer shafts and they are a weak point. The narrow liners wear quickly and become a point of oil leakage. This is a known problem, and many people solve it simply by throwing out both balancers. The balancer supports are plugged with bushings, and the oil channel of the balancer chain tensioner is also closed. The solution is common even in Europe, where sets of plugs are sold.
According to reviews, without balancer shafts, the B235 motor does not start to work with increased vibrations. True, there is some demandingness to the engine supports – on cheap non-original cushions, it can shake, and on a good hydraulic support works smoothly.
Hydrocompensators
The B235 engine’s hydrocompensators are not eternal at all. They begin to fail in small batches when the mileage exceeds 150,000 km. In practice, the only good replacement are hydrocompensators from the manufacturer INA.
Turbine
The turbine Garrett GT17 not the most charged versions go about 150,000 km. Usually due to seal wear, it ejects oil into the inlet. This is evidenced by blue (bluish) smoke from the exhaust pipe.
The Mitsubishi TD04 turbine of the charged versions of the B235 engine is more durable and survivable. It can go over 300,000 kilometers without problems.
Lightened pistons and related problems
Lightweight pistons of the B235 (B205) engine are prone to wear, they do not bear the loads imposed on them well and fall apart. This is especially true for the B235R version, where they could also burn through. In general, a B235 engine block punctured by a piston is a common phenomenon.
Thinner piston rings themselves have a reduced life, “thanks” to what by the mileage of 200 000 km this engine began to consume oil for carbon monoxide, which was not previously on Saab’s engines.
Oil pump
Lightweight oil pump in rare cases can fail because of the workings between the rotor and the housing, there are cases of jamming of the pressure reducing valve. All this leads to a drop in pressure in the lubrication system and serious wear of the engine friction pairs. Oil pressure at idle should be at least 1 bar, and about 2.5 bar at 2000 rpm.
Liners
The overall lightweight design of the B235 engine has resulted in weak liners. They simply wear out. And worn liners lead to oil loss through increased clearances. The reduced capacity oil pump is not able to compensate for these losses. Usually on the B235 engine, the third liner is scuffed and rotates, because the loss of oil pressure affects it most severely – hence the channel to lubricate the camshaft liners is lost.
But before this liner is rotated and pinched, the other liners and crankshaft main journals will be worn out and scratched. In the most unpleasant cases, the crankshaft supports (crankshaft bed) lead, and such a defect is not recoverable.