Greetings

At idle, in Park - every 12-13 seconds my ACE system surges. I cannot tell if the surge is starting at the pump or the valve block, as the noise is very similar at both ends. If I had to pick, I'd say it was actually a bit louder at the valve block. All I know for sure is that it's like clockwork.
Count to 12 and.... surge. It's like it's trying to pump something but can't.
Anybody seen this behavior before?

In general I don't think my ACE system is loud. The pump itself sounds fine, and I never hear the system running. I've never driven a non-ACE Disco, but I'm 99.9% certain ACE is working as I take some turns pretty fast and the truck handles very well. No lights on, but I only have an OBDII scanner. If ACE has thrown a code, I don't know.
Fluid level is good and swirling when running. However, I don't know the complete history of the truck. Given what I found in RAVE, I would expect to not hear anything from the ACE at idle.
Any and all observations appreciated! Thanks.

From RAVE:
Vehicle not moving
When the engine is running and the vehicle is not moving, both DCV's are closed, locking fluid in each side of the actuator pistons. The hydraulic pump draws fluid from the reservoir and passes it at very low pressure to the valve block. Because both DCV's are closed, after the fluid passes through the high pressure filter, it is directed through the pressure control valve to the reservoir. The pressure control valve is open fully to allow the full flow to pass to the reservoir. The DCV's will remain closed until the ECU detects a need to operate.

 

Don't know if it's normal or not but mine has been doing that for as long as I've owned the truck, about 5 years now. As you say, like clockwork, it has never changed it's behavior in all that time and never presented any problems so - if it ain't broke.....

 

Mine too, never paid it much mind.

 

I get a ticking noise from my valve block which stops if you pull the relay. all works ok

 

Thanks for the replies. With your confirmations, I shall now add the noise to the "Ignore - it's Normal" list. Even if it's not normal, it doesn't seem to be causing any issues with mine or yours.

Thanks again.