rattling noise after letting off throttle

[510TURBO]

yes i did my searches but it is not coming from my tranny im thinking maybe the tension pulley or my water pump since i overheated it a couple times last week the sound is coming from my turbo and DP area thanks in advance.

 

[terik.m]

when my water pump went bad it made a marble like sound.

 

[510TURBO]

+1

when my water pump went bad it made a marble like sound.

thats what im thinking since i never heard it until my car overheated last week

 

[510TURBO]

anymore

opinions:frown:

 

[terik.m]

have you tried to take off the serp belt and check to see if the water pump bearings are bad? when mine went bad it made a God awful noise similar to what you have described.

 

[510TURBO]

have you tried to take off the serp belt and check to see if the water pump bearings are bad? when mine went bad it made a God awful noise similar to what you have described.

yeah thats what im doing today, hopefully its that, it makes a horrible sound and makes you think the worst but from the sound of things you know its something minor. like i rather have a rattling noise because you know something is loose then a knocking or tapping noisethanks for the input:biggrin:

 

[mtocrs1]

Turbo heat shield

If removing the belt doesnt get rid of the noise you might also want to remove the Turbo heat shield and try again. Sometimes the heat shield likes to start making noises after a recent repair.

 

[toofastforyou]

Could the noise be coming from the turbo when you suddenly lift your foot off the pedal?...This is mostly noticeable when using a K&N type open air filter...

Claude.

 

[tito]

hello there Everyone

Don't mean to hijack the post, but mine does something similiar.....when the car is on and it gets warm, it begins to do some weird tap noises in the engine, the temp was checked at 175 deg to 182 deg..nornal, i took the belt off no noise??? it sounds like hard burps of water gushing through, it has a new water pump, thermostat with 2 drilled holes 2 help circulation, the sound was there before these changes so nope the holes in the thermostat not the problem, i know for sure its the water since when the engine is turned off the noises continue for about 10-15 seconds, if i release the radiator cap vent arm the noises stop asap!?? i already purged the coolant twice new radiator,also the engine with all passages purged, good passage of water, all hoses are new, ???? now heres a question is the water pump differnt from a regular engine to a turbo? maybe my old one was bad and this one is bad now or wrong one? help... the noise does sound terrible, the last thing i tried is this, i turned the car on got warm, i opened the radiator cap, manually accelerated the engine in order for it to circulate the water, i then held the acceleration as i filled the radiator with more coolant, closed the cap, and released the acceleration, noise decreased but it now sounds like marbles?????

 

[davidf]

Sounds like the internal waste gate flap. Typical on these cars or at least the ones I've owned.

 

[tito]

i'll check it out, but how does that relate with coolant?

 

[BILL HAINES]

Loose bolts

Check the ac-alt bracket, these bolts work loose after time mine were loose... Good luck....

 

[DailyDrifter]

Sounds like the internal waste gate flap. Typical on these cars or at least the ones I've owned.

Off Topic , but you should post some pics of that NSX sometime, sexy cars to say the least :biggrin:.


Ok now to get serious. Take the belt off and spin each accessory by hand and listen for any abnormal sounds. Your tensioner could also be worn and be slapping around. Also check and see that your exhaust isnt hitting anything on the frame, my buddy Ben had a problem with the exhaust hitting the sway bar. Also like Claude said make sure its not just compressor surge from the air hitting the compressor wheel when you snap the throttle closed. Or try and find someone near you to help you track the problem down.

 

[aminga]

Is the Air on defrost? I have an off brand A/C compressor that cools well enough but rattles like a box of rocks when you let off the throttle.

 

[GrndNatnl]

My A/C compressor makes a little rattling noise once in a while too, but typically during around-town driving and slow acceleration from stops and crawls, etc.

 

[510TURBO]

Is the Air on defrost? I have an off brand A/C compressor that cools well enough but rattles like a box of rocks when you let off the throttle.

yeah mine rattles too but only when im using it this happens only when i let off the throttle thats why i think its the water pump

 

[GrndNatnl]

Could also be the tensioner as well. I remember replacing the pulley on mine a few years back due to some rattling or squeeking noises.

 

[turbo39151]

How old is the timing chain? Mine used to give a dieseling sound when I let off the throttle. I hunted and hunted and couldn't find a thing. Looked at chain and it was a little slack. Swapped it and problem gone.

 

[510TURBO]

bad news guys

changed the water pump, my pulley has a little play in it but the worst news is that sound i been searching for is my rod bearing

 

[mtocrs1]

That sucks

Sorry to hear the bad news.