Determining the location of the malfunction by listening — noises in the engine compartment

With a cold engine, faint knocking noises from the engine bay are not necessarily a cause for concern. If the engine is warm, then the appearance of hard metallic detonation and rumbling noises, on the contrary, almost always indicate the presence of serious defects. Most often, such defects occur in the connecting rod bearings, less often they can appear in the main bearings of the crankshaft. Defects in bearings are always a complete revision of the engine. if you have sensitive hearing, then, fortunately, bearing defects can be detected even at their initial stage. If this is the case, then sometimes it is enough to replace the plain bearing shell of the corresponding connecting rod or main bearing - the specialist will, of course, advise you to carry out significant repairs (grinding, nitriding, new installation of the crankshaft and the like) engine components.

How to recognize bearing defects

Accelerate the engine to medium speeds out of motion and then abruptly release the gas. If you hear then a slight detonation noise (nak-nak-nak) and notice this noise also during hard acceleration, you can immediately send the engine to a special workshop. Such noises are a typical sign of a connecting rod bearing defect.

If you initially ignored the noise (nak-nak-nak), then after a few kilometers you can hear hard «click-click-click»: the bearing defect has aggravated, the bearing shell has melted and, with a high probability, the crankshaft has already been damaged. You can already forget about cheap repairs - now you have to put up with a completely replaced engine or some of its components. If a rumbling noise is heard from the crank mechanism, rising synchronously with the engine speed, the trouble happened with the main bearings. Stop the engine immediately and have the damage diagnosed by a workshop.

If you still wait a little longer with this, then a new danger will appear - you will have to scrap the entire engine block: bearing shells «revolve» at the same time, in the places where the bearings are located, they instantly lead the block to unusable iron scrap. All this will require repair costs in the amount when your dealer can no longer offer the old cylinder block as a replacement.

PRACTICAL ADVICE

If the drive belt is broken If the red charging control light on the dashboard lights up while driving, this means that the drive belt is broken. Often, in addition, you can notice further hard impact on the course of the wheels or on the front spoiler in the engine compartment. In this situation, in no case should you move on. Since the water pump is driven by the drive belt, the cooling process stops, «dormant» the coolant boils quickly and you risk major engine failures. Therefore, you must immediately install a spare belt or have the car towed to the nearest workshop.