ENGINE COOLING SECTION KI. General Description KI.1 3. Maintenance KI.2 4. Drain/Refill Procedure KI.3 5. Radiator & Cooling Fan KI.

Transcription

1 ENGINE COOLING SECTION KI Sub-Section Page General Description KI.1 3 Maintenance KI.2 4 Drain/Refill Procedure KI.3 5 & Cooling Fan KI.4 5 Fan & Re-circ. Pump Control KI.5 8 Feed & Return Pipes KI.6 9 Water Pump & Thermostat See Section EI Page 1

2 Coolant Flow Circuits Thermostat Open Front mounted radiator Air bleed plug feed pipe thro' chassis Outflow from turbo Outlet from head Return to water pump Header tank Heater matrix Oil/water heat exchanger Heater return pipe thro' sill Feed to turbocharger Air bleed plug Re-circulation pump k74c Thermostat Closed Outlet from thermostat housing closed by-pass circuit from head Heater matrix Return to water pump Outlet from back of head k74d Page 2

3 KI.1 - GENERAL DESCRIPTION The engine cooling system comprises an engine driven water pump, a front mounted radiator with two electric cooling fans, a header tank, re-circulation pump and associated ducting, pipework and controls. The centrifugal water pump is mounted on the front face of the cylinder block, and is driven by the toothed cam belt. Water is discharged from the pump into the front of the cylinder block, around the cylinder liners and up into the cylinder head, before exiting the engine via an outlet spigot on the LH front of the head. open circuit: From the thermostat housing outlet on the LHF of the cylinder head, a moulded hose connects with the main radiator feed pipe which runs inside the right hand chassis side rail, before feeding the front mounted radiator. An air bleed screw is provided in the radiator inlet hose. The engine cooling radiator is of aluminium construction with plastic end tanks and is mounted together with the a.c. condenser and twin 100mm diameter electric cooling fans as a package. This pack is fixed by the radiator mounting panel horizontally on top of the front crash structure, with the condenser lowermost and the cooling fans on the top side of the radiator. The glass fibre composite crash structure also serves as a duct to direct airflow from the body nose air intake, to the underside of the cooling pack with the cooling fans supplementing the ram air flow when required, and a moulded deflector panel directing the hot air exhausted from the pack through an outlet grille in the front body. The left hand outlet spigot on the radiator feeds a return pipe routed down the inside of the chassis left hand side rail, which is then connected by moulded hose to a plastic constructed oil/water heat exchanger (see below) mounted on the right hand side of the cylinder block, beneath the inlet manifold. The outlet end of the heat exchanger incorporates two spigots, the larger, lower spout being connected by a short hose to the inlet of the water pump. The smaller, upper spout provides a water pump by-pass route directly into the cylinder head. Heater circuit: The heater circuit is fed from the right hand rear of the head via a re-circulation electric pump mounted behind the engine, to a hose running across the back of the engine bay to join an aluminium pipe routed along the outside of the right hand chassis siderail, within the composite sill member. The front end of this pipe rises over the end of the scuttle, penetrates the plenum/scuttle baffle panel, and connects to the heater matrix mounted in the chassis front climate chamber. The heater return circuit is similarly routed along the left hand side of the chassis to the left hand front corner of the engine bay, where a moulded hose including an air bleed screw, joins this pipe to the oil/water heat exchanger inlet connection. In conditions of 'heat soak', after stopping a hot engine, the electric re-circulation pump is energised under engine ECU control to pump coolant through the heater circuit and limit the potential for localised boiling within the cylinder head. Turbocharger cooling: The bearing housing of the turbocharger is water cooled via a feed tapped off the main coolant return hose at the LH front of the engine bay, with the return routed via a steel pipe beneath the exhaust manifold to the top of the header tank. Header tank: The translucent plastic header tank is mounted at the left hand side of the engine bay, and connected from its underside to the heat exchanger inlet pipe. An air bleed hose connects a spigot at the LH front of the cylinder head to the top of the tank. by-pass circuit: When the thermostat is closed, the radiator feed circuit is shut off, forcing coolant to leave the cylinder head via the heater circuit for optimum cabin heating and defrost performance. The correct pressure balance of the system is maintained by a water pump by pass hose linking the right hand front of the cylinder head to an oil/water heat exchanger outlet spout. Oil/water heat exchanger: An oil/water heat exchanger is fitted alongside the right hand rear of the cylinder head, connected into the coolant return pipe to the water pump inlet, and with oil pipes to and from the oil filter adaptor. With a cold Page 3

4 engine, this device transfers heat from the coolant to the oil to speed the warming of the latter, and on a hot engine, heat is tranferred from the oil to the coolant to help control high oil temperatures. KI.2 MAINTENANCE The engine cooling system uses a header tank to ensure that the system remains completely filled, and also to accommodate expansion of the coolant with increasing engine temperature. The tank is mounted at the left hand side of the engine bay, and is fitted with a 108 kpa (15 psi) pressure cap to raise the boiling point of the coolant to over 120 C (250 F). WARNING: Do NOT attempt to remove the pressure cap from the header tank when the engine is warm as serious scalding could result from boiling water and/or steam. Coolant is hazardous to your health and may be fatal if swallowed. Keep coolant out of reach of children. Coolant is hazardous to animals and may be fatal if swallowed. Clean up spilled coolant and do not leave in open containers. The level of coolant in the translucent header tank will rise as the engine warms up, and fall as it cools down, and under normal circumstances it should not be necessary to add any coolant to the system between services. If overfilled, the excess coolant will be ejected when the engine is warm. If underfilled, overheating may result. When the engine is completely cold, the level of coolant in the header tank should be close to the horizontal moulded seam running around the centre of the tank. If topping up is required, wait until the coolant has fully cooled before slowly unscrewing the filler cap and allowing any remaining pressure to escape before finally removing the cap. In order to maintain protection from freezing damage and metal corrosion, use only an approved coolant mixture (see below) to top up the header tank. Refit the cap, and turn clockwise until secure. NOTICE: If the cap is removed when the engine is warm, the coolant may boil and a small coolant loss may occur. The completely cold header tank level should be checked at the first subsequent opportunity. Anti Freeze/Corrosion Inhibitor It is necessary that the coolant contains an anti freeze with corrosion inhibitor to protect the engine and heat exchangers from both frost damage, and corrosion of the metallic elements. In order to protect against these dangers as well as raising the boiling point of the coolant, the Europa is factory filled with a 50% concentration of Havoline XLC, which is a mono-ethylene glycol coolant using organic acid technology (OAT) to provide increased corrosion protection compared with conventional coolant additives. A yellow label around the header tank neck identifies the coolant type used. The corrosion inhibiting carboxylic acids in the OAT coolant tend to remain in solution rather than being deposited on the internal surfaces of the cooling system, thus improving heat transfer and extending service life. Havoline XLC is the only recommended coolant product, and at 50% concentration provides freezing protection down to approximately - 40 C. Even in warm climates it is recommended that the concentration is not allowed to fall below 25%, in order to maintain full corrosion protection. The simplest means of checking the antifreeze concentration is to measure the specific gravity (density) of the coolant at a known temperature, using a hydrometer. The following table provides a general guide: Concentration 20 C 60 C 25% % % The coolant density reflects the effective level of mono ethylene glycol, and not the level of corrosion inhibitors present, whose effectiveness diminishes over a period of time. The coolant should therefore be renewed every 4 years to ensure optimum corrosion protection. In areas where the tap water is extremely hard (exceeding 250 parts per million), use of this water will lead to 'furring up' of the system over a period of time. In such areas, distilled, de ionised or filtered rain water should be used. Page 4

5 Fin Cleaning At service intervals, the matrix of the engine cooling radiator and a.c. condenser should be checked for clogging by insects, leaves and other debris. If necessary, use a water jet from both above and below to clean the fins, taking care not to damage the fragile tubes or distort the finning. At the same time, check the integrity of all cooling system joints, and the condition of all flexible hoses. In snowy conditions, ensure the radiator air exit is cleared of snow before driving the car. KI.3 DRAIN/REFILL PROCEDURE To drain the engine cooling system: 1. Remove the undertray from beneath the nose of the car. 2. Disconnect the radiator feed and return hoses from the front ends of the thro' chassis pipes, and collect the draining coolant. Remove the header tank cap to speed the operation. Note that draining of the heater matrix is not easily possible with the unit 'in situ', and that if draining for the purpose of coolant change, this volume should be disregarded. If necessary, flush the heater matrix using low pressure mains water via a suitable hose. To refill the system: 3 Refit the hoses to the feed and return pipes and refit the undertray. 4. Remove the left hand front wheelarch liner and open the air bleed plug on the radiator outlet hose. From within the engine bay, open the air bleed plug in the heater return hose at the left hand rear of the engine bay. 5. Fill with the recommended coolant mix via the header tank and close the bleed plugs when a steady stream of coolant is expelled. 6. Start the engine and allow to idle, and periodically open the bleed plugs to allow any trapped air to be expunged. Top up the header tank when necessary, and fit the pressure cap when required to prevent overflow. When the cooling fans have cut in and then out, stop the engine and allow to cool. Re-check coolant level when fully cold. KI.4 - RADIATOR & COOLING FANS The engine cooling radiator, a.c. condenser and cooling fans are secured together as a package and are mounted horizontally on top of the crash structure, condenser lowermost, radiator above and the two cooling fans on the top side of the radiator. Bonded to the front and rear of the condenser are steel channels which incorporate mounting brackets to attach the unit to the lower flanges of the engine cooling radiator. This package is then fixed to the composite radiator mounting panel by two rear brackets attaching to the condenser/ radiator flange, and two front brackets attaching to the top flange of the radiator. Fans For access to the radiator fans, the front clamshell must be removed (see sub-section BT.4). Each fan is secured to right angle brackets bolted to the front and rear of the radiator top flange, via a single fixing bolt. The rear fixing is readily accessible, but the front fixing is restricted by the outlet ducting of the radiator mounting panel. In order to avoid removing the complete mounting panel and cooling pack, it is recommended to cut an access hole in the ducting and blank off the hole on completion. The harness for each fan motor is routed between the radiator mounting panel and crash structure at each front corner of the radiator, where a connector block is provided to link to the main harness. Page 5

6 To replace: 1. Remove the front bumper and clamshell (see sub-sections BT.3 & BT.4). 2. Recover the refrigerant (see section PM), and release the condenser connections using two spanners at each joint to prevent damage to the condenser. Immediately cap all ports. 3. Drain the coolant and disconnect the radiator hoses. 4. Unplug the fan harness connector at each front corner of the radiator mounting panel. Disconnect the horn (RH side) and alarm siren (LH side) and feed the harnesses through the crash structure. Release the front harness from the radiator panel along the rear edge, RH side and front edge. 5. Release the 3 fixings securing the RH downward extension of the panel from the side of the crash structure. At the LH side, release the 4 similar fixings, two of which secure the alarm siren. 6. Remove the 3 screws securing the radiator panel to the crash structure along the top rear edge, and the 3 along the front edge, and withdraw the panel and cooling pack assembly. 7. To remove the cooling pack from the mounting panel, release the four setscrews along the front of the panel, and the four screws along the rear top edge, and slide the pack from the panel. 8. Unbolt the condenser and fan assemblies from the radiator as necessary. CAUTION: When handling the radiator and condenser, take care not to damage or distort the delicate finning, and impair efficiency. 9. Refit components in reverse order to disassembly, ensuring that the foam seals are correctly refitted to protect from vibration and optimise airflow through the matrices. Refill with coolant and bleed as detailed in sub-section KI.3. Re-charge refrigerant system. mounting panel Cooling fan front mounting bracket rear mounting bracket A.C. condenser Engine cooling radiator p106a Page 6

7 & Condenser Mounting inlet hose mounting panel rear mounting bracket front mounting bracket outlet hose Air bleed plug fan rear mounting bracket fan front mounting bracket Engine cooling radiator FRONT fan A.C. condenser Condenser front fixing stud Condenser rear fixing screw p105a Page 7

8 KI.5 - RADIATOR FAN & RE-CIRC. PUMP CONTROL The two cooling fans are fitted on the top side of the radiator/condenser package, and the coolant recirculation pump is mounted behind the engine. Both the fans and pump are controlled by the engine management ECU using data provided by the engine coolant temperature sensor and a.c. pressure sensor. Cooling Fans The cooling fans are switched as a pair, and will operate at half speed (connected in series) when coolant temperature reaches 98 C on rise (94 C with a.c. on), and switch off at 96 C on fall (92 C with a.c. on). If coolant temperature rises to 105 C (96 C with a.c. on), the fans will switch to full speed (connected in parallel), reverting to half speed on fall at 98 C (94 C with a.c. on). Note that the temperatures displayed on the instrument panel may differ from the programmed values described above due to damping lag. The fans are also activated by signals received from the air conditioning pressure sensor; the fans will run at low speed for pressures between bar, and at high speed for pressures over 18 bar. Certain types of ECU detected engine fault will also cause the fans to be activated as an engine protection measure. If the ECU receives a coolant temperature sensor signal voltage outside of the acceptable range, a default setting equating to 60 C will be substituted, and the cooling fans will run at half speed. Fan Control Module The cooling fans, re-circ. pump and a.c. compressor are controlled by a relay module mounted on the protective cover for the wiper motor, and accessible via the front services compartment. Important Note: The a.c. relay module is identical in appearance to the engine relay module, but the function of the two modules is different and they must not be transposed. The a.c. relay module A117M0038F has a brown label marked YWB100800; The engine relay module A111E6024F has a white label marked YWB Re-circulation Pump A coolant re-circulation electric pump is mounted on a bracket secured by a clutch housing bolt at the right hand side of the block, and is plumbed into the heater supply line. When energised, the pump circulates coolant through the heater system, drawing coolant from the back of the cylinder head, and pumping it through the heater matrix and back to the engine. Fans/compressor relay module FRONT ï Fusebox p108a Page 8

9 Heat Soak After ignition switch off, the ECU remains live for a minimum period of 1 minute for coolant temperatures below 75 C (at time of switch off), extending progressively to a maximum period of 10 minutes for temperatures over 90 C. If, during this period, the coolant temperature exceeds 110 C, the re-circ. pump will be activated and will run for a maximum period of 6 minutes, or until the coolant temperature falls to 50 C. If, during the ECU live period the coolant temperature rises to 120 C, the cooling fans will run at slow speed in addition to the re-circ. pump, for a maximum period of 2 minutes, or until the temperature falls to 70 C. Defrost Enhancement In order to speed windscreen defrosting/demisting, when coolant temperature is between 2 C and 60 C, the re-circ. pump will be activated to boost coolant circulation through the heater matrix, commencing 10 seconds after engine start up. The pump will continue to run until 30 seconds after either 1400 rpm is exceeded, or the coolant reaches 60 C. KI.6 - RADIATOR FEED & RETURN PIPES The radiator feed and return pipes are routed through the chassis main side rails, feed on the right, and return on the left. Each pipe is located by a grommet in the chassis front closing panel, and by a pair of shaped foam blocks inserted into the rear end of each chassis rail. On initial build, the water pipes are fitted before the crash structure is bonded to the front of the chassis. A new chassis assembly is supplied with both water pipes and the crash structure pre-fitted. A pipe may be replaced in service without the crash structure being removed by the following procedure. WARNING: The machined edges of the chassis extrusions and the ends of the drive fasteners can present sharp edges and points representing a potentially serious health hazard. It is strongly recommended that industrial gloves are worn, and other suitable precautions taken to provide protection from cuts and abrasions. 1. Remove the undertray from beneath the nose of the car and drain the coolant by disconnecting the feed and return hoses from the front ends of the chassis pipes. 2. Remove the front clamshell (see section BR.4). 3. Releasing the hoses from the rear ends of the water pipes requires that the fuel tank be removed. Access to these joints is available only via apertures in the inner walls of the chassis siderails within the fuel tank bay. To remove the tank refer to sub-section LM.4. The hoses are secured to the rear ends of the water pipes by spring clamps requiring a suitable tool to release. 4. Using the access provided from within the fuel tank bay, push the water pipe forwards until obstructed by the crash structure. It is recommended that a suitable hole be cut in the flat vertical face of the crash structure at this point in order to allow the pipe to be withdrawn forwards. 5. To refit, retrieve the two support foams from inside the chassis rail. Fit the grommet into the hole in the chassis front closing plate, and smear with rubber grease. Feed the pipe through the access hole and grommet, and position with mm of pipe protruding ahead of the grommet. 6. At the rear end of the pipe, fit two foam support blocks onto the pipe, and push into the chassis rail ahead of the fuel tank bay aperture. 7. Refit the hoses to the front and rear ends of the pipes. 8. Blank off the access hole in the crash structure with a suitable grommet. Page 9