Sound in intake manifold clanking sound

have a compression test done as it may be a loose valve seat insert
balance shafts are just shafts and unless you have done a bearing for the shaft it will not make a clanking sound as there is no pressure applied to the shaft
basically a balance shaft is like a flywheel that takes vibrations out of the motor

• ENGINE 2.4L

DESCRIPTION

N·m

Ft. Lbs.

In. Lbs.

Balance Shaft Carrier to Block-Bolts

54

40

-

Balance Shaft Gear Cover-Double Ended Fastener

12

-

105

Balance Shaft Sprocket- Bolt

28

-

250

Balance Shaft Chain Tensioner-Bolts

12

-

105

Balance Shaft Carrier Cover-Bolts

12

-

105

Camshaft Sprocket-Bolt

101

75

-

Connecting Rod Cap-Bolts

54 +1/4 turn

40 +1/4 turn

-

Crankshaft Main Bearing Cap/Bedplate - M8 Bolts

34

250

-

M11 Bolts

41 +1/4 Turn

30 +1/4 Turn

-

Crankshaft Damper

136

100

-

Cylinder Head Cover- Bolts

12

-

105

Flex Plate to Crankshaft

95

70

-

Flywheel Mounting Bolts

81

60

-

Engine Mount Bracket Right-Bolts

61

45

-

Exhaust Manifold to Cylinder Head-Bolts

23

-

200

Exhaust Manifold Heat Shield-Bolts

12

-

105

Intake Manifold - Lower -Bolts

28

-

250

Oil Filter

20

15

-

Oil Pan-Bolts

12

-

105

Oil Pan Drain-Plug

27

20

-

Oil Pump to Block-Bolts

28

-

250

Oil Pump Cover Plate-Bolts

12

-

105

Oil Pump Pick-up Tube-Bolt

28

20

-

Oil Pump Relief Valve-Cap

41

30

-

Spark Plugs

28

Timing Belt Covers - Front Covers to Rear Cover-Bolts

12

-

105

- Rear Cover-Bolts

12

-

105

Timing Belt Tensioner Assembly-Bolts

61

45

-

has it always done it? do you have an aftermarket cold air intake on it? if it has always done it...i think u r talking bout the vacuum relief of the intake manifold. no big deal

Does "clank occur when shift fwd/rev ? Worn U joint. Can be hard to change. DIYrs bash it out with hammer(after removing driveshaft from truck) Techs use press. These trucks prone to rear flange splitting @ U joint cap. Drive shaft bearing ? :"It dont got 1" Pinion bearing in diff supports driveshaft. sometimes pinion flange nut backs off, but usually worn pinion bearing causes it to seem that way.
Block wheels,trans in neutral,crawl under and rotate shaft by hand. Listen for noise.Follow sound to movement( there should be ALMOST none.Where 1 part moves and the part attached doesnt,,theres your prob. btw "drive shaft bearing USED to be a joke.

It sounds like you have a lifter that is sticking or the nut that holds the rocker arm has come loose. In eighter case you need to remove the valve cover to see if its the nut tightten to 20 ft lbs If its the lifter you can try to free it and make it move but to replace it you need to pull the head off Be sure this not an exhust that you are hearing they can sometimes sound similar especialy if the exhust manifold has a small crack in it. That can be repaired with out removeing the manifold

drive shaft u-joints will make clanking sound putting in gear or have bad vibration to it . it can be pion bearing in rear-end it will do what you are saying . but check driveshaft , sometimes you can see if drive shaft has play in it move side to side .

check this out. https://youtu.be/qo-WPpRbhaM

i have hd this problem and did exactly what u did ad itnd up being the dip stick tube got turned although mounted and was slpping the crank shaft

The knocking or ticking is going to determine if it is in the top end, lifters, push-rod or rocker arm issue or the bottom end that would include pistons or bearings.
If it is a ticking noise, it will more than likely be a valve train issue.
If a knocking noise, piston or crankshaft related problem.

Attached is a web site that you can listen to a piston slap which is a known issue for your 4.3.
Listen to the noise and see if it sounds similar to your problem. A piston slap will generally sound as though it is coming from the central area of the engine.
Listen to the recording and let me know.
Regards,

I have had the same problem at almost exaclty the same milage. 2004 Mazda 3 3 door hatchback (5 door sedan). I was told by the service manager that there is a valve in the manifold that fails and starts flapping, sounded just like a collapsed lifter. I think this should be covered under warranty. If not the mfg warranty the emissions? .. good luck.