I have an 85 4runner with lift gears and tires, it runs strong but still has to work really hard to get over some of these mountain passes. I got the temps up quite a bit and blew one of the hoses ( the one that is right behind the alternator ) after replacing it when my engine gets really hot (has to me going up mountain passes) it will leak antifreeze out the front of the engine somewhere near where that hose blew. My water pump is the first suspect but the shaft seems to have no play. Anyone have any ideas on where the antifreeze is coming from? Also why would this issue pop up after blowing a hose?

Second question: who sells a quality 3 core radiator that will bolt right in?
-John

Sounds like you whacked your t'stat along with the hose.

Also raise the front end up a little bit and turn the heater ON. Leave radiator cap OFF. Run engine for about 20 minutes to burp the air completely out of the system.

NAPA has a 3 row Modine; also try www.radiator.com or www.radiatorbarn.com

I have kind of the same problem. but i never blew a hose or anything, i just noticed that it was leaking one day. It is leaking froma bolf under the EFI throttle body. any ideas what that could be?

I don't see how any of the described symptoms indicate a dead t-stat. Please explain.

Anyone use 1800radiator.com? Is their stuff good?

Is it possible that my leak is from the water pump weep hole, which may let some by if the pressure is high enough?

The weep hole in the water pump will leak if coolant is leaking past the inner seal at the pump shaft. If this is happening, that means that the bushing on that end of the shaft is also getting coolant leaking through it which is bad news for the bushing. Basically means the pump is on its last legs if indeed that is where the leak is coming from.

And on the blown hose, assuming it did not fail from being too old and brittle, is if the engine compression is overpressuring the cooling system. This can hapen if there is a head gasket leak between a cylinder and cooling passage. A cooling system pressure test can detect this (look for pressure rising with engine RPM) or a chemical test of the coolant can also detect if that is the cause of the problem:
http://www.arrowheadradiator.com/head_gasket_or_combustion_leak_test.htm

Well it only comes out of the front of the engine when it is HOT! the temp does not rise with the RPMs, only with altitude and grade. It's tough to trouble shoot this because I have to take it out to a big steep mountain and get it really hot to have it leak. That puts me out in the middle of nowhere with an issue on my hands - hence my seemingly lazy questions.

But to be more clear, if antifreeze is coming out the weep hole then it will come out all of the time, correct?

-John

Coolant under pressure will leak out of the point of least resistance. Probably the hose that blew was the weakest thing, your water pump seal is next. Key thing is to cure the disease and not treat the symptoms. I did the same thing on my old daily driver, had a hose blow, then the radiator popped, then radiator caps started releaseing hot coolant and finally I found out it was a leaking head gasket that was allowing engine compression to over-pressure the cooling system. And in my 4Runner, had similar issues, all related to a partly clogged radiator that led to mild overheating and that in turn lead to a failed head gasket. Mine would overheat at high speeds and on steep grades. Replaced the radiator and fixed the HG problem and all has been fine since.

I reread your post--so it's not spiking right away; just getting hot...
Have you looked for any bubbling in your reservoir? That generally points to the HG. In addition to what 4Crawler suggests, low compression in adjacent cylinders tends to point to a HG as well.

Back to the radiator for a sec- if you lightly touch the radiator fins after the truck has warmed up, and have cool spots, you've got clogs; sounds like you're going to pick up the 3-row and toss it in there anyway.

1986xcab, there are 2 water bypass lines there at the t'body; inspect them to see if they're cracked or rubbed thru.