24runners

We bought a 94 4runner with a blown motor. We are replacing it with a reciently rebuilt motor out of a wrecked 94. We have everything in, but the water is not circulating. Brand new thermostat and radiator. We replaced the water pump with the one off the blown motor. We took the thermostat out and it pumped fine. We put the thermostat in boiling water and it opened.


?!?!?!?!?!?!?!!? Can someone please help us figure this out?

Keith B.

You need to specify which motor FYI.
First suspect in 'no-cooling' situations is always the radiator itself. Are you sure it's good? It can look fine on the outside, and have worked fine with the old engine, but it picks its own time to finally clog up enough to cause problems. Second easy to think of possibility is big air gaps in the cooling system...though running the engine should eventually push all or most of the bubbles out. Did you start the engine and watch the gauge go up, up ,up, for a few minutes, then shut it off? There still may be air in the system. Some folks say if you park the vehicle pointing uphill, the steeper the better, it'll help the air circulate out. That's all I have for the moment.

eric-the-red

If the coolant is circulating fine with the thermostat out then it sounds like the thermostat isn't opening. Either it's defective, installed backwards or the coolant isn't getting hot enough to open it.

abecedarian

How long did you let the engine run before deciding the coolant wasn't circulating? I ask because it takes a little bit for the hot water to get to the thermostat and cause it to open.

And again, which engine?

sotb3

my guess is it's a 3.0 and the system is notoriously slow to clear it's throat of bubbles--sometimes an angle and/or milking the hoses abit helps, but as long as you are definetely filled to the top, take a jug with you and point it at your favorite hill/wheelin' spot--watch your temp and have fun burpin' your baby--