tubing in engine compartment

[caw_86]

i was replacing my ground straps in my 98 tahoe, and while reaching around to tighten the nut on the rear engine block ground, i found some 1/4" poly tubing, about a foot long just kind of back there. im not sure if this goes anywhere, or if its been cut. im not very familiar with what all components are in the engine compartment. Did these vehicle use tubing for anything? i forgot to grab a pic before i left for work today

 

[1998_K1500_Sub]

i was replacing my ground straps in my 98 tahoe, and while reaching around to tighten the nut on the rear engine block ground, i found some 1/4" poly tubing, about a foot long just kind of back there. im not sure if this goes anywhere, or if its been cut. im not very familiar with what all components are in the engine compartment. Did these vehicle use tubing for anything? i forgot to grab a pic before i left for work today

Vacuum hose perhaps?

On my Suburban there’s a vacuum line in that area which terminates on a solenoid which is mounted on the firewall on the passenger’s side, in proximity to where you were working.

 

[caw_86]

Vacuum hose perhaps?

On my Suburban there’s a vacuum line in that area which terminates on a solenoid which is mounted on the firewall on the passenger’s side, in proximity to where you were working.

i havent driven it yet since i found it to tell me if something isnt working, what does a vacuum line go to?

 

[1998_K1500_Sub]

i havent driven it yet since i found it to tell me if something isnt working, what does a vacuum line go to?

As I said, that vacuum line "terminates on a solenoid which is mounted on the firewall on the passenger’s side, in proximity to where you were working."

On my 1998 Suburban, that solenoid acts to "switch the vacuum on / off", and apply it to a vacuum-operated water valve that's in the coolant circuit. See the attached pages from the service manual and my notes within.

You may or may not have that solenoid on your Tahoe. If you don't have the solenoid, then you shouldn't have a vacuum line. Net-net: The line you see would be for some other purpose.

 

[caw_86]

As I said, that vacuum line "terminates on a solenoid which is mounted on the firewall on the passenger’s side, in proximity to where you were working."

On my 1998 Suburban, that solenoid acts to "switch the vacuum on / off", and apply it to a vacuum-operated water valve that's in the coolant circuit. See the attached pages from the service manual and my notes within.

You may or may not have that solenoid on your Tahoe. If you don't have the solenoid, then you shouldn't have a vacuum line. Net-net: The line you see would be for some other purpose.

thanks.


looking at that picture in the doc, that is about the exact length and location i found it. must have bumped it off jamming my arm down to the frame to get a bolt

 

[1998_K1500_Sub]

looking at that picture in the doc, that is about the exact length and location i found it. must have bumped it off jamming my arm down to the frame to get a bolt

Check it and report your findings.

 

[caw_86]

Check it and report your findings.

Either a previous owner deleted the hot water control valve or it never had one, but had the tubing to connect to it.

Seems odd to run it with coolant running through the heater core at all times

 

[east302]

You should have had it (you have the solenoid, only pickups didn’t have that system) and may want to plug the vacuum line. When the MAX detent is selected on the a/c temperature dial, that solenoid is energized and applies vacuum to close the water valve.

Not sure if you’d see a small vacuum leak if the line isn’t connected or plugged when the solenoid is energized - might be something to look into. Or just unplug the solenoid connector.

My 98 two-door, hard line from PCV fitting and soft line (1/8” fuel hose since that’s all I had) to the water valve:

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

 

[caw_86]

You should have had it (you have the solenoid, only pickups didn’t have that system) and may want to plug the vacuum line. When the MAX detent is selected on the a/c temperature dial, that solenoid is energized and applies vacuum to close the water valve.

Not sure if you’d see a small vacuum leak if the line isn’t connected or plugged when the solenoid is energized - might be something to look into. Or just unplug the solenoid connector.

My 98 two-door, hard line from PCV fitting and soft line (1/8” fuel hose since that’s all I had) to the water valve:

Thanks for the info, list of todo’s just keeps getting longer

 

[Eskimomann209]

That water valve sucks!
They tend to get mushy or brittle and disintegrate, might be why it was deleted!
But I still end up replacing rather than deleting.