HEXA

ENGINE 38  Connect compression tester to adapter and tighten vent knob.  Crank the engine with starter motor by 200- 350 rpm approximately. Pressure gauge needle will start rising. Continue cranking till gauge needle stops rising any further. Note down the reading. Loosen vent knob to make sure the tester needle returns to zero. Repeat this operation for remaining cylinders.  Minimum compression pressure in each cylinder should be 23 ± 1 bar.  Low compression pressure may be due to leakage past valves / piston rings / blown cylinder head gasket. To ascertain the point of leakage, spray small quantity of clean engine oil in to cylinder showing low pressure. If it improves, wear in piston rings / cylinder bore is indicated. If it does not, leakage past the valves is indicated. If compression pressure of adjacent cylinder is also on lower side and equal, it may be due to blown cylinder head gasket. d. Fuel System : Check the Fuel system for fuel flow. If the flow is restricted change the filter/ rectify the defect. Check for any kink or blockages in the fuel lines. Check “Water in fuel indicator” in the instrument cluster, if illuminated drain the water from the sedimentor. e. Clutch Slippage :  Clutch slipping can be confirmed by any of the following two methods:  Drive the vehicle with normal load in 3rd gear on level ground and let the speed drop down to approximately 15 kmph . Now press accelerator pedal fully. With slipping clutch the vehicle speed will not pick up and also clutch burning smell will be noticed. If this does not occur and vehicle picks up speed, it indicates that clutch does not slip. f. Brake Binding :  During driving apply brakes number of times and then shift gear to neutral position and check free rolling of vehicle. Check brake drums/brake discs for overheating and if necessary jack up the vehicle and check wheels for free rotation. ii. Excessive Engine Oil Consumption : High engine oil consumption may also lead to overhauling of the engine but before proceeding to overhauling, check following points:  Make sure that there is absolutely no external oil leakage i.e. from the camshaft oil seal, crankshaft oil seal, oil sump gasket, oil pump gasket, cylinder head cover gasket, turbocharger oil feeder and return lines etc.  Ensure that the oil separator in the cylinder head cover is properly mounted.  Check that no excessive oil found in the intercooler piping and OMS is functioning properly.  If no external leakage is found, determine the exact engine oil consumption, as per following procedure. Determining Exact Engine Oil Consumption : CAUTION  Do not make a rough estimate of engine oil consumption by noting the kilometers covered by the vehicle at any random stage and finding oil consumed from the topped up position taking into consideration dipstick level and oil sump capacity. Procedure : 1. Once it is doubted that engine oil consumption is higher, place the vehicle on a level ground. 2. Ensure oil level in dipstick in its max position (Oil Qty – 7.5L ). 3. Warm up the engine so that oil temperature is 75º- 80º C . 4. Take a clean vessel; place it below the drain plug of oil sump. 5. Drain the hot oil into the clean vessel. Drain it fully. 6. Screw in oil sump drain plug and tighten it. 7. Weigh the vessel along with oil. Let this weight be ‘w1’ gms. 8. Refill the weighed oil into the oil sump. Do not spill any oil. The vessel used for draining should not be used for any other purposes. 9. Drive the vehicle approx. 200 - 300 km . This drive should include at least 30 - 40 kms . of highway or similar road, vehicle running at about 60 kmph. 10. Let this drive distance be ‘D’ kms.