Windhield washer tank empties.....

"93 TS. I'm coming again with this mystery: I fill the windshield washer tank full.....and without any known reason, after a long trip...without any use of the washer...the tank goes empty. I've tested everything: disconnect the pumps electric supply, testing the tank for leaks, testing the pump seals for leaks.....all with flying colours. I just know that for no reason (that I can imagine) ...the tank goes empty. Does anyone else suffer from that mystery...or better, have solved it ?

I have theorized that vacuum created by speed at the rear of the vehicle would suck fluid from the rear nozzle !!! ...but have not verified that theory by pinching the rear feed tube....I should try. But I'm opened to any other theory....

I had a similar problem recently with my coolant reservoir. Started leaking for no known reason. When I removed the reservoir, I found that the bottom had been patched with fiberglass matte and epoxy. I peeled it off to find a nice, oval, melted hole....any guess? Yeah, heat. Lots of heat. From the infamous welder-non mechanic that repaired my passenger strut tower. I replaced it with an after market reservoir. .cheers KEV:grinyes:

Hi LMP

Did you consider running a "loop" in the hose for the rear windshield washer line? I would think that is where the washer fluid is draining through. I purchased a new style check valve from GM recently. Just a thought. Good Luck.

Isolate & plug the hose near the tank, make sure it's the one going to the rear window washer.

Had a similar problem with my TS, although took a week or so to empty the tank. Turned out to be the gromment the pump fit into, replaced with a regular wiring grommet of approprate size.
Also had a problem with a check valve leaking many years ago, removed it
Jeff

Lot of good suggestions....clamp off both lines during a long trip, and recheck level.......if low, it's the tank, grommet to the pump(s), or pump(s) itself...........

If level is ok, then you know it one of the line circuits......easy to check the w/s line by pinching on end and blowing through the other end......the rear one, being much longer and hidden would be hard to find.....

If there was no leak from the reservoir, unclamp the w/s line and see if the problem is there or not.....this will determine which circuit is at fault...

Seriously doubt your vac theory for the rear circuit.....