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noise from engine compartment

I have a 125k mile 1990 Nissan Sentra which started making rattling and knocking sound a couple of hundred miles ago. The noise is heard from somewhere around the engine, but only when the engine gets warm/hot, e.g. when I drive in a traffic, not on a highway. Sometimes the intensity of the noise goes from loud rattling and knocking to somewhat softer sound or even no sound at all with rare bursts of rattling, however the type of noise is always the same. These variations in the rattling/knocking intensity occur on a second scale. It does not matter if the car is accelerating or in idle. The warmer the engine, the more time the noise is in its louder mode. I thought the noise could come from the radiator fans, but once have heard the noise with the fans off. Could it be exhaust, belts or water pump or something else that can be relatively easily checked? Any advice and suggestion would be greately appreciated. yuri strukov

Reply to
ystrukov
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First thing is to go through the whole engine compartment looking for anything loose or missing bolts, or in the process of falling off.

Check the accessory belt pulleys and tensioner wheels (if it has any) for a loose pulley or a severely chunked up belt.

Second choice would be damaged or falling off heat shields on the exhaust pipe.

It could also be the timing chain guides/tensioners, but it usually only rattles in certain RPM ranges (around 2000 RPM IIRC).

Reply to
E. Meyer

You have to look at everything there, but based on time and mileage I'd say it's in the exhaust system. Those connections up front there are made to articulate some with the movement of the engine. With wear and rust they get loose, but not loose enough yet to cause a noticeable exhaust noise.

Reply to
MaxAluminum

The two responses before me, both missed something. You obviously don't have a clue where the engine is in this car or how to open the hood. Before you kill someone with your tinkering, take the car to a garage and get an estimate for the repair and then pay up.

Reply to
pete selby

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