Mine lasted about a year from the time I noticed it was loosing fluid....and about a week from the time I first heard the gurgling sound.

i have a '94 runner w/the 3.0 and i never heard the gurgle, but it did have what sounded like an exhaust leak that would go away when the engine warmed up. lasted about 6 mos. that way before one day it hydro-locked in kaiser parking lot after a doc. appt. that was crap! it eventually started and got us home though. my 22r in my p/u has been gurgling now for about 6 mos. i've heard of em goin 50k like that. engine preformance doesnt seem to be affected too much except i notice she cools off really quickly.

Take some of the coolant and put it in a container and let it sit. If exhaust is mixing with it , it will look somewhat oily and the contaminated stuff will separate out like oil and water.

If indeed it is the head gasket perhaps how much time would it a take to replace? Say if I'm doing it with a friend who has rebuilt engines before. Are those ebay kits any good? $95..

Well I replaced the thermostat and it still does the same thing. What is happening is the coolant gets hot and then it goes into the overflow reservoir. I let it cool down and I open the radiator up and its low so then I fill it backup and then a day or two later the overflow reservoir is fill to the top. So I dump it out and start all over. While I was doing this I looked at the radiator cap and it the rubber piece that goes around the top of the cap was split in half. So we will see if thats the problem.

Sounds like you possibly found the trouble. If the radiator cap is bad, it will overflow the overflow bottle thus emptying the radiator.
Get a Toyota cap only, the others are not worth it.
Danny

i think by know you would know if it was your headgasket you would have low water....burning oil....water in oil....or vice versa....lots of signs for it....i had the same water rushing sound in my 88 runner....when these motors start getting high miles and do blow gaskets....and the coolant rusts or whatever the case my be....small areas start to get blocked....and thats what your case is....you heater core is has some of the passages block (or restricted) which makes for high pressure on one side....and the water is backed up cause the heater core is restricted....flip your control the cold (blue area) see if the rushing sound goes away....if it does....there is your answer....

i actually picked up a 88 runner with the radiator and the heater core plugged....temp would be fine....but if i put any load on the motor (towin my trailer) it would over heat and the rush sound only went away when i turned the knob to cold.....replaced both radiator and heater core problem solved.....

hope this helps good luck....

I have been loosing coolant out of my overflow reservior for the last 20K miles (about 1-2 qts. per 3000 miles) and also have the gurgling sound when I turn on my heater. However my truck runs great and I haven't noticed any fluctuating temps. I'm pretty sure my HG is blown, but what are the consequences of holding off on replacing it?

Could let go altogether, fill the cylinders with coolant and hydro-lock your engine. All thought I doubt it. But engines have hydro-locked in stranger ways!!!!!!!