overheating - Toyota Nation Forum : Toyota Car and Truck Forums

Dat280z · 08-17-2008, 12:39 PM

I got a call from my dad the other day telling me something is wrong with the radiator. Later he showed me that coolant were rushing out and steams were everywhere while he was driving because the top portion of the radiator cracked. So I got a brand new radiator from NAPA and replaced it. After 10mins of driving the car overheated to red. I checked and it's seems like the coolant flow isn't running or that's what I think. The upper hose was hot as expected and the top portion of the lower hose(connects to the thermostat housing?) was warm. But the lower portion was pretty cool. Is that how it suppose to be or something is wrong as expected.

uibalnme · 08-17-2008, 03:58 PM

Change the thermostat. Seems like it isn't opening to allow coolant to flow through anymore.

Stillrunning · 08-17-2008, 06:16 PM

Well after the water runs through the rad it's supposed to be cooler than the upper hose. The thermostat opens and closes depending on water temp. It may be stuck/sticking but before you replace it a common error is not getting all the air out of the system. Raising the front end as you fill helps vent air. Start out with cold engine, remove rad cap, start engine, use safety glasses, allow engine to heat up and watch for coolant flow at the rad cap opening, careful not to put your head directly over the rad opening in case the coolant shoots up. When you see flow with water hot and no more air seems to be venting replace rad cap. Usually some overflow out the rad cap opening will occur as coolant heats up depending on how full the system is. Shut engine off and fill overflow reservoir to proper level. Take the car for a short ride not far from your house and watch the heat gauge. If it shows proper heat range then you're ok. Leaving the engine to cool down and re-checking the overflow reservoir is a good idea.

Dat280z · 08-18-2008, 11:15 AM

thanks a lot guys...really appreciate it. I will try those first and if it's still a problem then I guess it's the water pump. Is there a sure way to test to see if the water pump is out or not?

1996camry · 08-18-2008, 12:06 PM

another thing you need to check your fans

TURN ON your AC with an engine idle. Two fans should run when AC turns ON.

When you engine run, does your temp. gauge pass (nOrmal) gauge?

when you take the old thermos out, make sure you know the position of the ball DOT position.. try to put new thermos in the same way...

GO for OEM thermostic...it only 1-20 bucks... CAll your local Toyota Dealer before you go... SAVE yourself a trip....

Kep · 08-18-2008, 04:16 PM

A quick water pump test is to run the engine until the thermostat opens and then watch the water flow through the radiator cap. Since you're not sure if the thermostat has an air lock or is itself failing I would recommend removingt the thermostat and buckling it back up. Then you would see the water flow right away.

^+1 on Stillrunnings post first.

Kep

Dat280z · 08-21-2008, 03:19 PM

update kiddies....It's fixed!! Turned out the thermostat was sticking so i replaced it with a new one. Drove around with the AC on full blast and still didn't overheat. Thanks a lot guys

Mike Gerber · 08-21-2008, 04:39 PM

Try driving it around with the A/C off to test it. When the A/C is on, both cooling fans automatically come on. Just make sure the fan(s) come on without the A/C being turned on. The car has another system based on coolant temperature in the radiator that turns the cooling fans on when needed, when the A/C is off. You want to make sure that system works too.

Mike