countryboy227

This morning I decided to go coyote hunting. Its a balmy 11 degrees when I go to leave so I started my 4runner to let it warm up a bit and I left.
I drove out to the gas station and filled up and went to wally world for some stuff. Everything has been just fine so far.
So I get going down the road and after about 10 minutes I noticed that the heater was blowing alot hotter that normal. I checked the temp gauge and its wayyyy up there.
I pulled over cranked the heater on full blast popped the hood to check for leaks and there weren't any.
I checked the temp and it went from way hot to normal in about a minute. I squeezed the upper radiator hose to see if the pump was doing alright and it was pushing back like normal except for the occasional surge.
I limped it home and it never tried to get hot the whole time. When I got back I checked for leaks again and there was some coolant blown in the engine compartment but it looked like it might of came from the overflow because it was FULL.
After it cooled off I topped it back off with antifreeze an let it run to temp and squeezed the upper hose again and there was pressure on it but it wasn't trying to push back and there was a squeeking noise that wasn't there before but i really couldn't locate it.
Could it of maybe been froze up? I am in TN and it usually don't push single digits for temps.
Or is it time to have some work done?

toytech76

if its blowing it out the coolant res, its most likely a blown h/g.

GSGALLANT

Same symptoms I had when my coolant started freezing (or slushing, I guess)... mind you it was -15 deg F when it happened to me. I only had 40% coolant in my system at the time. Now I always mix it 50:50 to give me protection down to approx -35 def F.

Just for reference, you would have to have less than 25% coolant (so more than 75% water) in your system to have it freeze at 11 degrees F.

gpcollen1

maybe the thermostat stuck for a bit

Squiddy

I think it's bad juju for hunting coyotes

MTL_4runner

X2

I had mine do the same thing and it forced an overheat situation because all the ice crystals prevent the thrmostat from reaching temp and opening despite other areas of the engine overheating and possibly boiling the coolant out the overflow. If you refilled the cooling system, ran the engine on the highway again and when you feel the hoses at idle they were not overly pressurized, you probably escaped any head gasket damage.

In any case the remedy for it is to drain the cooling system and just run the premixed Toyota pink coolant. In fact anyone who lives in a climate where temps can approach 0 F should just use Toyota pink (super long life) coolant automatically.

GSGALLANT

Toyota Red at 50:50 or 60:40 (60% coolant to %40 water) also offers adequate protection at cold weather. The key is to ensure you've got enough coolant in your mix... one bottle of Toyota red is not enough to use to fully fill a system... you need 1-1/4 to 1-1/2 bottles... depending on whether you want 50% or 60% (and depending on whether you have a rear heater or not).

travis0077

just giving my two cents here but that is a classic sign of either A. having air in the system or b. thermostat stuck close and or radiator cap losing pressure and time to be replaced. both which are not hard to do on that vehicle.

GSGALLANT

rad cap not holding pressure will not lead to overheating by itself unless the water/coolant actually gets hot enough to boil (then the pump can't circulate it anymore). Rad cap not holding pressure will allow water/coolant to boil at a lower temperature, but that temp will still be higher than the temp at which the thermostat is designed to keep the engine. Thermostat stuck closed could do it, though.

travis0077

yeah i once thought that too but was proven wrong at a gm tech 1 class in detroit, michigan on a an cadillac northstar. scratched my head for awhile and didn't agree but jim hawthorne A.S.E master trainer for the class proved me wrong with a test on it and how pressure play's tricks with temperature on thermostat's but your probably right about the thermostat being stuck.

MTL_4runner

I agree but the premixed pink is cheaper, requires no measuring/mixing and lasts longer.
It's a been a no-brainer for me for a while, too bad I didn't take my own advice.

keithguts

Well this is my 2 cents. Isn't it true that if the rig overheats, it will blow cold air?

travis0077

yeah if you have no coolant in your car to go into your heater core.or thermostat doesn't open up to allow heated coolant to go to the heater core or you have a pluged heater core.

GOH10 Runner

What is the difference between pink and red.....i asked for the red pre-diluted at the dealer and they gave me pre-diluted pink.

MTL_4runner

Toyota red = long life coolant, must be mixed with water

Toyota pink = super long life coolant, premixed so add straight to your cooling system

GOH10 Runner

can you mix red and pink?

MTL_4runner

Ideally you wouldn't but, yes, you can.

GSGALLANT

FYI... the thermostat doesn't have to open to allow coolant to flow through the heater core. The thermostat opens to allow coolant to flow through the radiator. Even when the thermostat is closed, coolant is still flowing through the engine and heater core(s)... it just bypasses the rad.

element

I would probably start with a flush and replacement of the thermostat.

Interesting information...

travis0077

well take it for what you want but most of your bypass hoses on many vehicles run out of the intake and then to your heater core and then to your water pump, also to your over fill bottle many vehicles have different setups ford taurus, ford wind star , dodge spirit, and many more and if the thermostat as i had said before doesn't open on these models you will not have heated coolant going to your heater core .