I found a leak in my vacuum system and replaced the part. However the small pump still runs for quite a long time and I don't want to burn it out. When I disconnect the pump from the reservoir and plug the hose the pump shuts off like it's supposed to. I reconnect it to the reservoir and then disconnect each circuit on the output side of the reservoir but plugging each of these doesn't correct the problem. Since I opened up the system to replace the rubber elbow between the pump and the reservoir I'm now wondering how long does the pump need to run to initially pump down the system? The reservoir is fairly large and I'm thinking maybe the pump has to run for a while before everything is back to normal. How long would the pump have to run before I could be sure that the reservoir is leaking? Any help/info would be greatly appreciated. Thanks in advance!

 

I've never timed mine, but I would guess my V pump runs for 30 seconds or so after being off for a while. I'm pretty sure it is less than 1 minute.

 

Mine does the same thing. I replaced the ESOF solenoid...no fix. I replaced the pump because it wasnt working (probably burnt itself out from never stopping due to leak). Now I tun the key and the pump runs continuously. i plug it directly at the pump and it stops. Re insert the tube to the resivour and plug it at the tube..it stops. Theres a spot where a 2 hole elbow that plugs into the resivour. I put the pump to the the intake side of the resivour and plug the other hole to see if the resivour is leaking. The pump continues so I'm assuming it may be the resivour but I cant find any repair / replace info for the resivour. Anyone have similar issues?

 

i think i just fixed my esof problem. I used some golf tees to start at the pump and work my way down the line to plug the tubes at the tee and see if the pump shuts off. After the resivour it would take about 45 seconds for the pump tho shut off to empty the resivour. At the resivour it breaks off to the ESOF solenoid and ac heater valves. I plugged the ac direction and waited 45 seconds...shut off so ESOF is good (works as advertised). i plugged the esof (red) and reconnected the ac direction...the pump continued well past 2 minutes. After looking behind the dash and such(nothing noteable) I found a grey tube hanging down under the hood. This is taped to the black tube that goes to the resivour. Anyway it ws hanging down into the engine connected to nothing. i plugged it with a golf tee and 30 seconds or so it stopped. Checked my ac and the air works great...as advertised. My issue now is what does the grey tube connect to. It looks like it may dead end into a (something or other) connected to my coolant hose. The length is bout right and it fits but im not sure i understand the concept of putting it there. Any way, so far so good.

 

On any Excursion and Crew Cab truck, or any 2005 and up truck, the grey tube connects to a vacuum actuated valve on one of the heater hoses. On 1999-2003 Regular Cab and Super Cab trucks, the hose connects to a little plastic nipple on the heater core housing that does nothing more than act like a plug for the hose.

The purpose of this hose and valve is to prevent hot coolant from flowing through the heater core when the heater controls are in the OFF or MAX A/C positions.

 

Cool thanks for that. I guess i got it in the right place.

 

Mscheel,

I know it's been 5 years since you started this thread but I'm having the exact same problem as you did. What was your fix? New pump? Or new reservoir?

Thanks