How to use this chapter
Chapter 2B describes repair procedures that are prudent to carry out without removing the engine from the vehicle. If this information is used during the overhaul of an engine that has already been removed and installed on the stand (see chapter 2E), preliminary disassembly operations can be skipped.
Keep in mind that while some items, such as piston and connecting rod assemblies, can be removed and repaired without removing the engine from the vehicle, these procedures are usually not performed as separate operations. As a rule, several additional procedures are performed simultaneously (not to mention the cleaning of elements and lubrication grooves). Therefore, all such procedures are considered to be overhaul items and are described in chapter 2D.
Chapter 2E describes the removal of the engine/transmission from the vehicle and all overhaul procedures that can be performed after the engine has been removed.
Engine design
The DW series engine is a relatively new unit based on the well known and proven XUD series engine previously used in many Peugeot and Citroen vehicles. It is an in-line four-cylinder engine with a single overhead camshaft (SOHC). The engine is transversely mounted at the front of the vehicle. The gearbox is bolted to the left end of the engine.
The crankshaft runs in five plain bearings. Main bearing No. 2 is equipped with thrust washers to set the axial clearance of the crankshaft.
The connecting rods are supported by horizontally divided liners, which are located in the lower heads of the connecting rods. The pistons are connected to the connecting rods by means of piston pins, which are fixed with circlips. The pistons are made from aluminum alloy. Three piston rings are installed on them: two compression and oil scraper.
The cylinder block is made of cast iron, and the cylinders are bored directly into the block. On engines of this type, the cylinders are sometimes referred to as cylinders with «dry» shells.
The camshaft is driven by a toothed timing belt. On 1.9 liter engines, the shaft through the pushers acts on eight valves. Valve clearances are adjusted using shims installed between the valve stem and tappet. On 2.0 liter engines, the camshaft acts on the valves through valve levers and hydraulic tappets, which provide automatic adjustment of valve clearances. On all engines, the camshafts rotate in the cylinder head and are supported by bearing caps that are bolted to the top of the cylinder head. The intake and exhaust valves are closed by coil springs. The valve stems move in guide bushings pressed into the cylinder head.
Engine lubrication is provided by an oil pump, which is driven by (through chain and sprocket) from the right end of the crankshaft. The pump draws oil through a strainer located in the engine sump. After that, it drives the oil through a separate oil filter and delivers it to the channels of the cylinder block / crankcase. There, the oil is distributed and fed to the main bearings of the crankshaft and to the camshaft. The connecting rod bearings are supplied with oil through internal passages in the crankshaft, while the camshaft bearings receive pressurized oil. Camshaft lobes and valves, like all other engine components, are splash lubricated. An oil cooler is installed between the oil filter and the cylinder block to maintain a constant oil temperature at high engine operating temperatures.
Precautions when performing repair procedures
The engine is a complex unit, with many auxiliary units and other elements. The design of the engine compartment is such that every conceivable space is used, and in fact access to all elements of the engine is extremely limited. In many cases, work requires removing or moving aside auxiliary elements, as well as disconnecting electrical wiring, pipes and hoses or removing them from various clamps and support brackets.
When working on this engine, first familiarize yourself with the entire procedure while inspecting the vehicle and engine at the same time, and determine if you have the necessary tools, equipment, skill, and patience to perform the operation. Allocate sufficient time to perform a particular operation and be prepared for various; surprises. Any big job with this engine requires a certain amount of courage!
Due to restricted access, many of the engine photographs in this chapter were taken with the engine removed from the vehicle, if necessary.
Attention! When working with fuel cell elements, strict precautions should be observed. Before performing any work on the engine that requires handling fuel system elements or actions in the vicinity of such elements, refer to the special information given in paragraph 1 of chapter 4B.
Repair operations performed without removing the engine from the vehicle
Without removing the engine from the car, you can perform the following operations:
- A) compression test and leak test;
- b) removal and installation of the cylinder head cover;
- V) removal and installation of timing belt covers;
- G) removal, installation and adjustment of the timing belt;
- d) removal and installation of toothed pulleys, tensioner and intermediate pulley of the timing belt;
- e) replacement of the sealing cuff of the camshaft;
- and) removal, inspection and installation of the camshaft and valve levers / pushers;
- h) removal and installation of the cylinder head (engines 1.9 l);
- And) removal of carbon deposits from the cylinder head and pistons;
- To) removal and installation of the oil pan;
- l) removal, repair and installation of the oil pump;
- m) replacement of crankshaft seals;
- n) inspection and replacement of engine/gearbox mounts;
- O) removal, inspection and installation of the flywheel.
* Note. On 2.0L engines, access to the area between the cylinder head and engine compartment bulkhead and to the rear underside of the engine is so limited that it is not possible to remove the cylinder head while the engine is on the vehicle unless extensive additional disassembly is first performed (e.g. remove the front subframe and related components). Therefore, a description of the procedures for removing and installing the cylinder head is given in chapter 2D, taking into account the fact that the engine assembly with the gearbox is removed from the car.