Here's a short engine noise video for your collection...

[Tagmaster]

Ah hello again. I'm back with my 2007 RX400H, the one that had the inverter replaced by Lexus. ANYWAY, all has been well since then, until I got off the M1 on Sunday and a loud whirring noise was coming from the engine.

• It was not affected by speeding up or slowing down.
• Not affected by steering.
• Still ocurred when stationary

It was so loud when stopped in traffic, I heard someone on the pavement say 'what's that car making that noise for?' Ahem, yes, exactly. Typical St Albans. 

I've looked at a fair few other engine noise / belt noise / baring noise threads on here.

Oil level looks on the low side, just above the lower indent on the dipstick.

https://photos.app.goo.gl/YyL88k1rNdfCzwSG9

If that link doesn't work I'll upload the video. Note that it stopped on Sunday by the time I got home, this video is of it just starting to think about reocurring today. 

Any advice welcome. THANKS.

[Spacewagon52]

You said it was still there when sationary. Was the ICE engine running? It sounds like an electrical noise you get occasionally with the hybrid system but continuous.

Is the hybrid Battery charging?

[Tagmaster]

Thanks @Spacewagon52 yes the engine was ticking over. The hybrid Battery is charging fine. No temperature variation, fuel consumption just over 30 on the M1. It doesn't / didn't sound like any failing fuel or water pump I've had on other (non-hybrid) cars, nor any slipping belt... 

[Spacewagon52]

When the ICE engine stops and the car will run on electric, is the noise still there?

Just wonddring if it is an engine noise or the hybrid system making the noise.

[kenhall]

Brake actuator pump motor faulty? Normally this motor runs intermittently to maintain the brake accumulator pressure and is barely noticeable when operating.

[Brian26]

Possibily a relay chattering? But I think I would be taking it to a dealer pretty quickly. Anything making that sort of noise is not likley to be good.

Bri

[GSLV6]

Electrical of some kind, either a pump or motor.  Doesn't sound like the fuel pump which leaves hybrid system, perhaps electric steering motor (although why it should run like that I'm not sure) or brake actuator pump motor as above.  Low oil level would concern me but doubt that's the cause.  Mine never seems to use oil but I check to ensure it's always above half way up between markers (it usually registers full between services).

[Tagmaster]

16 hours ago, GSLV6 said:

Electrical of some kind, either a pump or motor.  Doesn't sound like the fuel pump which leaves hybrid system, perhaps electric steering motor (although why it should run like that I'm not sure) or brake actuator pump motor as above.  Low oil level would concern me but doubt that's the cause.  Mine never seems to use oil but I check to ensure it's always above half way up between markers (it usually registers full between services).

Ah thanks, I plugged an OBD reader into it and am showing no fault codes. also - wait for it - the noise stops when I turn the heating off! Is that brake actuator pump failure warning noise not some sort of buzzing? Either way, I will see how we get on heading to Essex on Monday. Thanks again. 

[Spock66]

On 3/3/2023 at 10:07 AM, Tagmaster said:

the noise stops when I turn the heating off

Fan blower motor?

[Tagmaster]

I am hoping so, on the basis this looks less costly / critical than the brake actuator pump. A further complication: I was just driving normally and got the cheeky old VSC Warning, followed by the Check Hybrid System warning. When going back to start the car, it's not starting. There seems to be power, it's just not starting. Feels like too much of a coincidence for this to happen / that it's associated with / a result of the cheeky noise...

[Tagmaster]

All restarted with a handy booster Battery. It's a Bosch Battery under the bonnet that went in just about 3 years ago. Does the team think its sudden drain does support a failing part elsewhere? I didn't think a failing fan blower motor would put excess load on the Battery. Maybe I'm wrong about that? THANKS AGAIN.

[Tagmaster]

NOTE: I tested it today on the way back from Essex (again) no heating there and back until the last mile. Turn the heater on and THERE YOU GO! VSC Warning and Check Hybrid System warning.

Who would have though a dodgy fan blower motor could take a car out of action?1

NB: Note that the OBD reader I have got did NOT show any errors, but erasing still worked and the car started just fine. 

Fan blower motor. Good lord.