cruisinkru

This one has me stumped. My 99 RX300 has this goofy gurgling rasping noise coming from the drivers lower dashboard area everytime I decellerate. I have been an ase master tech for 35 plus years and NEVER heard anything like this. It sounds like some of the old GM cars that had an A.I.R. pump and the noise they made when the air pump discharge was diverted to atmosphere. But it seems to be coming from the lower driver dashboard area. And the RX300 has no air pump....any help here is apprieciated

salimshah

Welcome to CL

Just a hunch, can you check if there is no air in the coolant. Run with heat on and let the engine cool overnight. Open the radiator cap (next morning), while the radiator is cold. Level should be all the way up.

If low, fill it up. About a cup of distilled should be OK to add, and if more is needed, think about mixing 50/50 with toyota red concentrate. Set the cabin heat to about 80 and run the engine with the cap off and fill up if the level drops further. Once the level is constant and full, after 3-5 minutes, cap the radiator and fill the overflow (min 1/2 way).

Check again in few days and you may need 1/4 cup.

If you keep needing more, then have the system checked for leaks.


Salim.

P.S The details are for members who are not mechanics.

cruisinkru

It is not a coolant issue,I said it sounds like a gurgling rasping rattling noise only on decelleration. I wish I could post the audio. Almost like the high vacuum level on decell is causing the hvac mode doors to rattle around ...its weird

salimshah

To confirm, change the AC mode away from Auto and set the mode to any one fixed position. They are electromechanical servos, so the above will ensure they are no longer toggling between position.

Salim

cruisinkru

nope,thats not it

cruisinkru

Sounds like the mode doors or door are rattling on there openings.....is that possible?? The noise is enough to make me wanna scrap this *****

salimshah

Electric (12v) servo directly drives the doors with mechanical linkage. There are springs in the set up that kind of help/resist the doors .. like detents.

When motor becomes weak then the servo works and works and then gives up.

Thinking out of the box ....

If some one has tinkered with your RX they may have removed the spring. Then the doors may be flopping around [worm gear usually would require a lot more force from the door side to cause a play, but once the system has been worked on, we can no longer logically solve it]

Just drop the glove box and the kick plate and wiggle the things. Nothing else it would eliminate your hunch that it is the door.

Salim

cruisinkru

is there anything else under the dash that could be affected when the vehicle decellerates? Like in a high vacuum condition?

salimshah

Your question is very wide. I can only state that unlike GM vehicles of old, there is no vacuum plumbing in the dash that operates the doors. There is vacuum piping in the engine compartment which runs along the cowl ... near the bottom edge of the front windshield.

There are plenty of wires behind the dash which can produce noise.

Salim

cruisinkru

Salim....thank you for hanging with me on this! Imagine you are driving at 45 mph,you lift your foot off the gas peddle and coast up to the stop lght,the whole time the throttle plates are closed there is a rattling,fluttering noise from under the center of the dash...I know I gotta dig deeper,and its going to be something stupid,i just know it lol I was hoping someone had the similiar problem...but no luck so far...

salimshah

I have been a member of the RX forum from the very start and only noise issues are:

1. Air in the coolant loop. (gurgling sound)
2. Air mode servo cycling through. (chatter)
--- only once ---
3. Things got past the the cabin air filter and blower started touching it.


That does not mean there can be no other causes.

I think you need an assistant to help trace the source of the noise. Use a mic/phone and move it around to determine where the sound is more pronounced.

Salim

salimshah

Try raising your RX passenger side front wheel. Check for the play in the drive shaft and the center support.

When you are decelerating, the drive shaft is being driven by the wheel and any play there can cause the noise you are hearing.

Do let me know if this is not your problem.

Salim

cruisinkru

Had the front wheel off as I did a timing belt replacement a few weeks ago as a PM. Still noisy from under middle of dash....I have about given up on it. I am s glad I do not work at a dealer and have crap like this come in and then lose my *** and waste my time trying to fix it. Stuff like this has what has driven me out of the auto repair business after being an ASE master certified tech for over 30 years.

salimshah

Did you check for a play in the shaft and or support? I could not tell from your post.

Salim

cruisinkru

no play,the noise is definately under the middle of the dash,and only on decelleration,no matter what position the heater controls are in.......now the damn blower only runs on low speed,I replaced the blower control module with a NEW one and still only low speed....my *** is aching!