1990SR5PU

Fellow RXers,

Thought you might be able to help out. I've got a flapping-type noise that is coming from my RX. Noise only occurs after starting from a stop, and ceases at around 20-22 MPH. It starts out slow, and then steadily increases in speed until it abruptly stops. I've been under the car, all looks good, can't find anything that looks amiss, loose, missing or beat on. It sounds a bit like a poker card in bike spokes, if you ever did that as a seven year old imitating Evil Kneval. Which I did.

The nature of the sound and the circumstances lead me to think it is something that begins flapping once air starts moving over it, and increases in flapping speed as air moves faster over it.

Thanks in advance. I sure hope someone's had this issue, and tells me to tighten this fastener...

Douglas

salimshah

I would check the exhaust hangers and heat shield next to the exhaust.

You may have to mount a camera to observe underneath.

Jack-up each side and in N, give each wheel a spin.

Also share when or what happened before the onset of the noise?

Salim

Lexmus

Can you tell if it is coming from the front or back of the vehicle? Left or right? If not, ride in different seats or even the hatch area, with someone else driving, and see if you can determine where it is. Also try with opening and closing the windows. Another thing is to be standing on the road as someone drives the car by you at 10-15 mph and see what you can hear.

ukrkoz

Ahem, how many miles? Was timing belt done? It might as well be flapping timing belt. Tensioner worn out and belt stretched. Just saying. And as oil pressure builds up with speed, tensioner kicks in.

1990SR5PU

63,000 miles. I do not believe timing belt has been done.

Sounds as though coming from right side of car. Much more difficult to hear if windows are down, wind noise drowns out flapping noise. This is a very subtle sound.

No discernible triggering event. Just noticed it one day after not having any noise.

ukrkoz

yeah, miles are a bit low for timing belt. Passenger side matches though, as engine front is there.There is a redneck way to check on this when driving. Cut suitable length of garden hose and secure one end with tape or something, close to area in suspicion. Feed the hose out the engine bay and into cabin though lowered window. It acts as excellent stethoscope. Of course, you can go fancy and place one of them mini cams somewhere in the engine bay.
But it's likely a loose piece of plastic somewhere. Heat shields are notorious about that.

1990SR5PU

I did drive in reverse, no noise.
Put car in neutral, revved it, no noise.
I'll check the heat shields again next time I'm poking around it.

Thanks!

salimshah

Please clarify if the noise is while the vehicle is in motion or standing still (any gear).

Salim

1990SR5PU

While in forward motion.

ukrkoz

Oh good. Then T belt is off da hook. You have loose something flapped by oncoming air flow. That's tough. You happen to have a large compressor? Blow air on various parts?
Does it sound like metal or plastic flap? They do differ.

1990SR5PU

Plastic sounding.

ukrkoz

You've been underneath your car. You saw all the belly pans. Any one of them can do this. Also scope tire well covers. One loose or lost fastener can cause this easily.

1990SR5PU

Still have the flapping noise. Recap of issue:
- faint flapping noise, best heard in cabin
- audible only between 15 and 20 MPH
- car must be in gear, moving forward, with accelerator depressed
- noise stops if gear selector moved to neutral or speed is over 20 MPH
- noise does not occur if I very gently accelerate

this has me stumped.

Lexmus

If you have to be in drive to hear the noise, and shifting to neutral stops the noise, all at the same speed, it is something tied to the transmission.
I have no idea what it could be as I have never torn down a transmission.

Audiqv8

The right side cv shaft is longer than the left side. It also has an intermediate carrier bearing. could be that the carrier bearing or the cv joint itself is making the noise while under load. The video shows the noise a failing cv shaft will make.