The Renault F4P engine is a 1.8 liter gasoline power unit introduced in 1998. It is based on the F3P engine of the same displacement, which was introduced in 1992. The differences between the two are in the cylinder head. The more recent F4P received a 16-valve cylinder head with hydrocompensators.
The F4P engine has a cast iron cylinder block, distributed injection, there is a phase regulator on the intake camshaft. This engine was installed on Renault Megane and Laguna from 1998 to 2005.
Renault F4P engine specifications
| Parameter | Characteristics |
|---|---|
| Fine volume | 1783 cm³ |
| Power system | Multi-point fuel injection |
| Engine power | 115 – 120 hp |
| Torque | 165 Nm |
| Cylinder block | Cast iron, R4 |
| Cylinder head | Aluminum, 16 valves |
| Cylinder diameter | 82.7 mm |
| Piston stroke | 83 mm |
| Compression ratio | 9.8 – 10.0 |
| Engine features | DOHC |
| Hydrocompensators | No |
| Transmission timing | Belt drive |
| Fasoregulator | No |
| Turbocharger | No |
| Oil | 4.8 liters 5W-40 |
| Ecological class | Euro 3 |
| Example service life | 250,000 km |
Renault 1.8 F4P engine problems
Like many engines from the 1990s, this motor is simple and reliable. Mechanically there are no problems with it. Usually annoying are oil leaks, malfunctions related to the operation of the lambda probe (rarely there is a second “lower” lambda probe in the exhaust system of this motor). In addition, the Renault 1.8 F4P engine is known among connoisseurs as a “shaker”. That is, shaking at its work – a matter of habitual and usual. In many cases, no measures, repairs and replacements do not help in the treatment of “shaking” of this engine.
A separate cause of “shaking” is low compression, so if the F4P engine shakes frequently, it will not be superfluous to check it.
Electrical wiring
And one more complex weak point of the engine Renault 1.8 F4P is the wiring. With age and mileage problems, i.e. breaks, fraying, oxidation and so on, happen to almost all wires and connectors.
It is not uncommon for shorted wires to cause strange engine behavior. For example, due to the destruction of the braid on the wires of the power booster pressure sensor and short-circuits, the engine speed may also float, increase randomly when driving in a rolling terrain or simply be high at idle.
Oil leaks
Periodically, the Renault 1.8 F4P engine requires repair work for oil leaks. Oil usually leaks from the crankshaft oil seal, camshaft oil seals, valve cover gasket, from under the plugs and from the phase shifter valve. Leaks on the camshafts are dangerous to get oil on the timing belt.
Lambda probe
Lambda-probe engine Renault 1.8 F4P perfectly diagnosed by a company scanner, the main thing that the diagnostician knows and understands what readings of the lambda are normal, and which indicate its failure (the signal from the upper lambda-probe should quickly fluctuate within the range of 0.1 to 0.8 volts).
Usually when the probe malfunctions, the engine starts to shake violently, there are strong dips in idle speed. You can try to remove the chip lambda-probe – if these symptoms pass, then the problem is in it.
Swimming, bouncing or sliding revs
Unstable, i.e. “floating” revs or rolling revs when the accelerator pedal is fully released on a Renault 1.8 F4P engine are usually caused by a dirty throttle plate or air infiltration through the seals on it or on the intake manifold.
Throttle valve
Throttle valve can “please” not only contamination and the resulting floating revolutions, but also a weak contact in its connector. In this case, the engine starts with strong vibrations and keeps high idle speeds. These symptoms are floating. In this case, you can try to disassemble the chip-pad on the wiring and tweezers to push the contacts.
Rubber sealing rings are installed on the flap on both sides. Over time, they sag, get stale and allow excess air to pass through.
Fuel injectors
Contamination of the fuel injectors may be one of the reasons for engine “shaking” at idle speed, when speeding up or when releasing the gas pedal. The injectors can be cleaned in an ultrasonic bath or with a carburetor cleaner, but this usually has no effect on engine shaking.
Ignition coils
Ignition coils don’t last long, and when they fail, they cause engine shaking – ignition skipping.
Phase Regulator Valve
Nothing usually happens to the phasoregulator valve. It can be periodically removed and its mesh-filters cleaned. If they are clogged, the engine stalls a few seconds after starting. Also clogged valve filters make the phasoregulator “starve”. However, more often replacement requires rubber seals, which over time oozes oil (and even floods the wells of the plugs).
Phase regulator
The phasoregulator on the Renault 1.8 F4P engine is the same as on the 2-liter F4R. It fails due to poor quality or unsuitable oil or infrequent oil changes. When it fails, the engine begins to “diesel” – to work with a loud rattle. It is a faulty phasoregulator that produces this noise. Also at its breakdown there may be problems with starting the engine, fuel consumption increases.
The phasoregulator must be replaced. It used to cost about $200 (only the original), but today it is almost twice as cheap. Again, in the past, for the sake of economy it was even silenced – it was removed, disassembled and some rubber bands were inserted between the injectors, which simply blocked it. The sound stopped, but the engine characteristics decreased – the engine lost noticeably in traction and consumed more.
Spreadshafts
Rarely, but there are cases of development on the shank of the intake camshaft due to a faulty phase shifter. However, such an unpleasantness even after replacing the phase shifter does not affect the normal operation of the engine. The main thing is that the scoring is not too strong, with the appearance of burrs.
Again, there may be a wear on the crankcase bed on the extreme neck of the camshaft next to the phase shifter. Because of this, oil will constantly leak there. In this case, you will have to think about replacing the cylinder head.
Timing belt
The timing belt on the F4P engine also drives the pump. It should be changed every 60 thousand kilometers of mileage. Or 4 years after the previous replacement.
The crankshaft timing belt gear on the F4P engine is installed without a key, although there is a slot on the shank – this is the legacy of the 8-valve predecessor. That is, the gear is pressed only by the bolt, and its position relative to the crankshaft as a whole does not matter. This makes it much easier to replace and install the timing belt. When replacing the timing belt, the crankshaft and camshafts are rigidly fixed with appropriate tools.
Turning the timing belt pinion is not that uncommon for the F4P engine. Of course, in this case the engine is scrapped and replaced with a contract engine.