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Discussion Starter · #1 ·
My 1996 Camry with a V6 overheats sporadically after driving it for a a couple hours or less in the heat. I noticed that my overflow tank will fill up almost to the top leaving the radiator low on fluid. Do I need to replace the hose that runs to the overflow tank? the radiator cap? Any help is greatly appreciated :thanks:
 

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Wont hurt to replace the cap. Questions:

  • Whats the status of the coolant, when was it replaced last?
  • What kind of coolant is being used?
  • Has the coolant been topped off? What coolant was used?
  • Any CEL codes including pending?
 
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Discussion Starter · #3 ·
Wont hurt to replace the cap. Questions:

  • Whats the status of the coolant, when was it replaced last?
  • What kind of coolant is being used?
  • Has the coolant been topped off? What coolant was used?
  • Any CEL codes including pending?
The coolant looks fine, it was replaced last summer.

Im pretty sure the coolant is a universal high-mileage type.

I topped it off a few weeks ago. Have been checking it regularly. Did not need much. I notice that if i lift the overflow bottle up, coolant will slowly drip back into the radiator and both will be full. Today when i did that I squeezed the hose and it flowed much easier and faster back into the radiator, which led me to think that the hose may have been the issue.

I do not know what CEL codes are..

Appreciate your help!
 

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Here is how the overflow works;
As engine heats up the coolant expands, the rad cap holds the coolant in until it reaches it's rated pressure, usually about 15psi.
The rad cap has two Valves, a larger out flow valve, 15psi, and a smaller in flow valve, 0psi.
The hose to the over flow tank must be air tight and clean on the inside, even a small leak or blockage will cause the system to fail.
The overflow hose must always be covered by coolant in the overflow tank, any air in that line will cause the system to fail.
The overflow tank must be vented at the top, so coolant can come in and then flow back out, an air tight overflow will cause the system to fail.
The overflow tank must be clean, any debris can get sucked into the hose and clogged it.
So coolant exits the rad at 15psi and into the overflow tank, as long as the engine stays at normal operating temp the overflow tank level should stay about the same, it will rise a little if engine is running warmer but just a little higher.
Once engine is shut off the engine coolant cools off and contracts, so the pressure in the system drops, and it will drop below 0psi, when it does the smaller rad cap valve allows coolant to flow back into the rad.

If rad caps main valve fails then it will allow coolant to go to the overflow tank at a lower pressure, causing more coolant to be in the overflow tank than normal.
If small valve on rad cap fails then coolant can not get back in, usually you will see a partially collapsed rad hose because there is negative pressure in the system when it cools down.

If overflow vent is plugged up then coolant can't come back in to rad because of negative air pressure in the overflow tank.

If overflow hose has a leak then air will be sucked back into the rad as it cools, air is easier to move than coolant, also if there is a leak in the cooling system air will be sucked in when engine cools, again air is easier to move than coolant.


Replace rad cap
Blow out overflow hose, check for leaks, make sure overflow tank is vented and clean.


If overflow tank is at a higher than normal level and it is bubbling, you have a blown head gasket or cracked head
 

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The coolant looks fine, it was replaced last summer.

Im pretty sure the coolant is a universal high-mileage type.

I topped it off a few weeks ago. Have been checking it regularly. Did not need much. I notice that if i lift the overflow bottle up, coolant will slowly drip back into the radiator and both will be full. Today when i did that I squeezed the hose and it flowed much easier and faster back into the radiator, which led me to think that the hose may have been the issue.

I do not know what CEL codes are..

Appreciate your help!
Need to verify it was all Toyota coolant. Yes, it matters!. You can't run down to walmart or autozone and slap anything in unfortunately. If that was the case need to know.
 

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Which is not correct,red organic coolant is red organic coolant,regardless of the label
red is still silicate free and can be used per application.
Just dont mix colors and youll be fine
 

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Which is not correct,red organic coolant is red organic coolant,regardless of the label
red is still silicate free and can be used per application.
Just dont mix colors and youll be fine
Nope. Color does not matter anymore. Need MSDS and/or proof of contents.
 

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Disodium fluorescein dye is added to antifreeze as an identifier since some different formulations(colors) are incompatible

Red is Red . . . . . .


Your US Toyota's coolant is made by Kost USA Inc
This product is sold under acouple other labels yet retains manufacturing point of origin
http://www.kostusa.com/asp/subantifreeze.asp?ID=100003


Look them ALL up right here,they cant sell it in the USA without a MSDS sheet
http://www.worldpac.com/msds/
 

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Also as I am tinkering around taking the overflow hose off and on am I needing to get rid of air in the hose? Or does the system autocorrect it


Sent from AutoGuide.com Free App

The overflow system is self purging, meaning any air coming out of the engine/rad cap will bubble up in the overflow tank, only coolant can be pulled back in to the engine since the overflow hose is always covered in coolant since it is at the bottom of the tank.

If you have air coming out of the engine and into the overflow hose/tank then you have a blown head gasket.

And on a cold engine nothing should come out into the overflow tank, after 5-10minutes maybe a little coolant might start to come out, but not much.

If you get air bubbles within the first 5 minutes then you have a blown head gasket, or a very bad coolant leak so engine was almost empty of coolant when you started it.
 

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Try run your car w/o thermostat and see if problem still exist. If it does then you most likely have head gasket issues. I've seen many aftermarket thermostat wont auto-purge out the bubble on but Toyota OEM will.
 

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If it over heats sporadically you have a problem with either the thermostat, the coolant temp sensor mounted on the radiator or possibly with the cooling fans. If the coolant temp sensor on the radiator fails it will cause the fans to not kick on even if the gauge on the dash say the engine is too hot as it operates off a different temp sensor. You could check that your fans both work by unplugging the coolant temp sensor on the radiator and starting the car. With out it plugged in the fans will stay on constantly. If the fans come on after unplugging then they are not the cause. FYI you only need one of the two to come on to keep the engine cool and it is very unlikely to have both fans fail and the same time. If neither fan works then it is almost certainly an electrical problem IE a fuse or relay. If the fans come on then leave the coolant temp sensor unplugged and drive the car for a while. If the over heating issues go away then it was your coolant temp sensor. If the car still over heats still then try turning on the heater while the car is over heating to check for hot air. If the thermostat is the problem then it fails by not opening and thus preventing hot coolant from going to the radiator and heater core so there would be little if any hot air.
 
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