brentleedragon

Hi I am a newbie here. Love the rig other than this problem.... so sorry for the long post....

I live in Eastern Washington and it's been getting in the high teens and mid 20's in temperature. I noticed (from my stock gauge) that it was running underneath the 1/2 way mark (About an 1/8th" down where it normally runs on the halfway mark). The car took a long time to get to operating temp.The heater also wasn't getting warm. Only time it would get warm was when I let it sit at an idle or am going slow. I went to change the Thermostat and flush the radiator out. When I popped the thermostat out it was gutted....meaning it was just the gasket and the top of the thermostat casing (no thermostat mechanism). To me that explained the 4runner running on the cool side. I flushed the radiator out put the new thermostat in ("Jiggle" valve at 6 o' Clock). And filled it back up and burped the air out of the system (jack the front end up slightly just to be sure). Everything seemed to be going okay, the heater was hot and it was about normal. So I put the cap back on and took it for a test drive. It didn't take even 5 minutes for the temp gauge to start going up. (I had checked the thermostat before putting it in and it was all good). I couldn't really figure it out...Radiator is newer, not clogged, lines look fine, everything seemed to be circulating fine, no fluid was lost internally and no external leaks. I put the old "thermostat" in and it is working like it did before (still not getting entirely warm).

I have a couple ides of what it could be, but was hoping someone could point me in the right direction. The coolant was clean when I drained it(no leaking oil/ at fluid or anything else in it). I'm thinking it could be the Coolant Temp. Sensor or something with my heads. I don't have any white smoke, missing fluid or loss of power so I am less likely to believe that one. But I am not sure...any ideas?

rworegon

Is the radiator free of mud and debris?

Was the radiator full when you drained the coolant? Did you put the same amount of coolant back in? Did you use a Toyota OEM thermostat of 82c/180f?

Is the fan clutch engaging properly?
What is the history on the timing belt? The timing belt drives the water pump.

brentleedragon

Timing belt was replaced about 50,000 miles ago.
The fan clutch seems to be in working order.
Coolant level was fine before drain and I put roughly the same amount back in.
Radiator is clean, I flushed it out and it was clean even when I flushed it.
And yes I used an OEM thermostat.

vital22re

iTrader: (2)

If it overheated off the bat like that, either the radiator is clogged or you have an air bubble in the block. pull off a rear heater hose and fill the radiator. I always take off a heater hose by the heater valve, remove the upper hose from the radiator and fill into the block using the upper hose. THen I reconnect the upper hose and fill the radiator.

brentleedragon

I'll have to try that.

My dad just told me when he was borrowing it the other week it threw him a code P0116...which is for the Coolant Temperature sensor...think that might be the culprit? Not really over heating but just saying it is? and Right now i t's running colder than it says...

I'll try redoing the the cooling system the way you said to see if that helps out at all.