[Malafax_dand]

I have been spending alot of time with the key in the accessory position and the hood open.
I noticed a very high pitched whine seemingly from the front of the engine. Possibly in the engine intake valley. The noise does not appear to be comming from the under hood ECU compartment (that is a different noise). This noise is fairly loud and constant. What could this be?
Again this is with the engine off and just the key in the ACC position.

 

[Dan_UK_1984]

Secondary coolant pump? Maybe the bearings are failing, although that's nearer the bulkhead than the front, but perhaps it's resonating?

 

[Malafax_dand]

Couple of followups,
I do not see a secondary coolant pump on the V8 engine cooling system for the BMW engine. Is a secondary coolant pump a Ford engine component? Would the secondary coolant pump run when the key is on?

 

[Dan_UK_1984]

The pump will run the whole time the ign is turned on, you can shut it down by turning the hevac panel off (just keep turning the fan knob till all the lights go out)

This is the info from the manual:

Auxiliary Coolant Pump
The auxiliary coolant pump is an electric pump that ensures there is a satisfactory flow rate through the heater matrix
at low engine speeds. The auxiliary coolant pump is installed in the engine compartment, in a rubber mounting
attached to the side of the LH suspension turret. Operation of the auxiliary coolant pump is controlled by a power
supply from the ATC ECU.

[attachment=0:1ya038vs]Aux Coolant Pump.JPG[/attachment:1ya038vs]

 

[Dan_UK_1984]

I may have circled the wrong bit, it may be the thing above and to the left!

 

[Malafax_dand]

Nice,
Thanks Dan. You went above and beyond on that one. My RAVE manual does not have anything on an aux cooling pump. My cooling diagram is completely missing that piece of information. I am not suprised that data is missing. In my electrical diagram, the EAS computer is completely missing from the Diagnostic port wiring diagram. I have since discovered that the EAS computer is indeed wired in, the manual is simply missing the data.

I will try the HEVAC control knob and see if I can trigger the noise.

 

[Dan_UK_1984]

Nice,
Thanks Dan. You went above and beyond on that one. My RAVE manual does not have anything on an aux cooling pump. My cooling diagram is completely missing that piece of information.

I think it was in the air conditioning section, it's purpose is to circulate the coolant at low revs through the heater where generally speaking the coolant doesnt pass through the heater matrix as it has a higher flow resistance than the main rad. The P38 was quite bad for this, in traffic or parked the heater would go cold under 1000rpm!