Weird circulating coolant sound

[HeadacheManNYC]

With the heat on, I’ve been noticing a pronounced intermittent hissing from behind the drivers side dash - definitely sounds like coolant circulating or air escaping.
Has anyone else noticed this?
Early VIN FE with about 10k problem free miles..

 

[HeadacheManNYC]

With the heat on, I’ve been noticing a pronounced intermittent hissing from behind the drivers side dash - definitely sounds like coolant circulating or air escaping.
Has anyone else noticed this?
Early VIN FE with about 10k problem free miles..

Should mention, it’s only audible at idle

 

[LCQ]

I haven’t noticed a hissing noise on my 1958. I’ve messed with the heater and ac settings a lot due to a low volume fan blower issue.

The only noises I can think of are the EV pedestrian noise emitter or the fuel pump pressurizing.

There are very apparent clunks and pressurizing noises from the fuel pump shortly after turning it off and also before starting iirc. These come from the driver side engine bay near firewall.

 

[HeadacheManNYC]

Here's a 40 second clip of the sound. It starts at about 7 seconds and slowly peters out after I shut the car off.
Sounds very similar to standing next to my refrigerator.

Feedback is welcome - I'm not crazy about taking it to the dealer for this where it will no doubt live for several weeks, but TBD.

 

[tacoshawn]

Our RX500h had the T24a-FTS, while we didn’t notice the sound I do recall the turbo has a separate electrically-driven liquid intercooler circuit. Perhaps this is what you are hearing?

Unfortunately our RX500h went back to Lexus under lemon law and our replacement RX350h is the A25A-FXS (different engine, no turbo) so can’t go give a listen in the driveway.

 

[CJF]

Unfortunately our RX500h went back to Lexus under lemon law

What was the issue? Engine related?

 

[tacoshawn]

What was the issue? Engine related?

Software related, it kept throwing CELs and Toyota Japan was unable (at the time) to provide a definitive timeline for the S/W fix to resolve. No mechanical issues.

So, after 45 days in the shop (and an RX loaner the whole time) we requested/received a buy back and bought a 350h.

If you have to go through a buy-back I really do have to share Lexus handled the buy back with complete professionalism and we got back every dime of our purchase price (mileage value adjustment waived under goodwill).

The RX500h had grunt and for being a cross-over I found it a fun drive. At the end of the day it is my wife’s vehicle and she is just as happy with the fuel-sipping 350h. And she got Nori Green which looks great and she loves the color.

 

[185]

Usually on the gas only models I would double check freon levels, but on a hybrid they use a separate hvac system

 

[LCQ]

Here's a 40 second clip of the sound. It starts at about 7 seconds and slowly peters out after I shut the car off.
Sounds very similar to standing next to my refrigerator.

Feedback is welcome - I'm not crazy about taking it to the dealer for this where it will no doubt live for several weeks, but TBD.

That video helps. I haven’t had that noise in mine. I’m pretty darn sensitive to random noises in vehicles too. Have you tried turning AC on/off while you’re hearing it to pinpoint if anything changes it? I’d try all the settings.

 

[HeadacheManNYC]

It's going to the dealer tomorrow - will report back.

 

[HeadacheManNYC]

Well, they heard the noise, noted it, said no codes or warnings were being put out, and to come back if it gets worse.
Incidentally, same story for the squeaky brakes in reverse - no TSB that they're aware of.