If we assume that you are worried because your engine produces strange noises and you would like to know whether the engine has too much play. You are suspecting play of the main bearings or big-end bearings in the crankshaft. You could dismount of course the engine and carry out specific measurements in the crankshaft and its bearings. However, you can also leave the engine in the car, just take off the oil pan, and carry out the measurement with Plastigage. You get the same information, only with much less expenditure.
Plastigage is a small plastic thread that is pinched, taking the starting torque exactly into account, in parallel to the bearing axis in the sliding bearing. The thread is as long as the support is wide. Taking the thread out again, the width of the strip is counter proportional to the bearing clearance. The play can be determined more exactly by comparing it with a special paper strip, normally provided together with the plastigage.You can apply this method to big-end bearings and main bearings. Indeed, the weight of the crankshaft and the flywheel must be compensated for with the latter by a jack if the engine remains in the car. Also you should take the different colours into account because the threads are prepared for different bearing play measuring ranges. 06/07