Ticking Noise in Engine When Idle

Posted on the 13 November 2019 by A2v

Ticking noise in the engine while idle often indicates the engine is not being fully lubricated. This is either because it lacks oil or it has low oil pressure. So then let's start by checking the oil level.
Car Troubleshooting
Lift the hood and find the oil dipstick. Then, remove the dipstick, wipe its end off with a rag, put it all the way back into the hole, pull it out again and check its reading. If it reads below the "full" line, the oil level is low.
If the engine has a low oil level, then poor engine lubrication is causing a ticking noise
As you probably know, the purpose of oil is to lubricate the engine. What this means is that oil acts as a microscopic barrier between the parts of an engine that rub against each other. Hence, the less oil an engine has, the more chance there is for certain parts to come in direct contact with one another (i.e. metal-on-metal). When this occurs, some sort of noise is usually given off. Now then, as far as this vehicle is concerned, the ticking noise is probably coming from the valve lifters, valve stems, or rocker arms.
What to do?
Add some oil.  Make sure you add the type of oil which is recommended in this vehicle's owner's manual.
If the engine oil does not have a low oil level, which clearly means that enough oil is in the engine. But if the oil pressure is low, the upper part of the engine won't get fully lubricated. Consequently, a clicking noise will occur. We can determine if there's low oil pressure by checking the oil light. With that said lets check.
If the oil light comes on while the ticking noise is occurring, then poor engine lubrication is causing noise. First off, proper lubrication is necessary not only to keep an engine running smoothly but also to dampen the noise that results when certain engine components come into contact with one another. A key factor in maintaining lubrication is oil pressure. As long as the oil pressure is sufficient, all of the engine components will receive an ample dousing of oil. 
However, since this car's oil light was on, the oil pressure must be low. This means that certain engine components such as the valve stems and rocker arms are not being fully lubricated. Consequently, they make a ticking noise as they operate. Now, the real question is, "What is causing low oil pressure?" Well, either the oil pan screen is clogged or the oil pump is bad (the latter is more likely). In summary, the oil pump is probably bad which is causing low oil pressure which in turn is causing poor lubrication and finally, poor lubrication is causing a ticking noise.

What to do?
In order to boost engine lubrication, the oil pressure has to be increased. As was mentioned in the explanation for this diagnosis, the oil pressure is low probably due to either a clogged oil pan screen or a bad oil pump. So then, take this vehicle to a garage and ask the mechanic to determine the exact cause of this engine's low oil pressure. Please don't delay in having the necessary repairs done since a poorly lubricated engine will quickly break down.
But, if the oil light does not come on while the ticking noise is occurring, then the oil pressure must be good. Therefore, this noise must be caused by something other than poor lubrication. With that said, the following might be the culprit:
(1) Loose valve
(2) Leaking exhaust manifold.
Loose valves or a leaking exhaust manifold will each make a nearly identical ticking sound. In both cases, the ticking will get faster as the engine revs up. A loose valve will slap against the rocker arm as the engine runs and thus cause a ticking sound. A leaking exhaust manifold will allow exhaust gases to leak. Then, with each cycle of the engine, a bit of leaking exhaust gas will make a ticking sound.

What to do?
You will need to take this vehicle to a mechanic for analysis and repair. Please mention the above two possibilities to the mechanic. If this engine has adjustable valves, it may only need the valves tightened. As far as the exhaust manifold is concerned, have the mechanic inspect the exhaust manifold bolts... they may be loose.
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