Hello all,

I'm in need of some advice or some direction. The cooling system in my car is not performing properly. It will push over flow of coolant into the overflow tank but it will not pull it back into the radiator when it cools leaving a lack of coolant to the engine. It has enough pressure to create flow but not a vacuum. I cannot find any visible leaks. There is not any coolant in the oil. There is not any white smoke coming from the exhaust.

Here's everything I've done:

Replace thermostat
Replace radiator
Replace water pump and timing belt(it was almost due anyway) Also, at the pump area there was a small amount of fluid leaking.*
Flush the system & bleed the system
Replace the section of hose that runs from radiator to overflow. (There weren't any visible leaks but I did it just in case.)

When bleeding the system I did have the heat setting selected. Also, here's something else which may or may not be pertinent, if I start the car and let it warm up and I've had the heat on and blower blowing it will not blow warm until I press on the gas to rev the motor.

 

The head gasket may be blown. Purchase a kit that tests for exhaust gases in the coolant from an auto parts store.

 

The bi-directional control valve for cooloing system expansion purge and refill is located in the RADIATOR CAP. It is operated under the principal of Boils gas laws that state when a liquid is heated it expands and when it is cooled it shrinks. Durring the cooling process, a partial vacuum is generated which draws the coolant out of the overflow and back into the cooling system. Change the radiator cap.

 

Currently not having luck finding an auto parts store that carries them. Or an employee that knows what they are. Thanks for the reply!

 

The new radiator came with one. Thanks for the reply Sir!

 

You could try this
http://www.toyotanation.com/forum/10...d-testing.html

 

The idea of checking the radiator cap was good, but Boyle's law pertains to gases not liquids. Liquids and solids actually expand and contract only a small amount when heated or cooled.

 

Buy a cap. mine was doing that and i put a 8 dollar cap on it and it fixed it

 

Call AutoZone and ask whether they sell or rent a Block Tester tool (renting will obviously be cheaper) and sell Block Tester fluid.

Walmart and Amazon sell this Combustion Leak Tester.

 

My local AutoZone is closed already but I went online and searched their website and it is available at my local store.

 

Man, that's awesome! Thanks!

 

Okay, I did the cylinder test as described in that thread on the Toyota forum. The glove did not flutter. One of the plugs came out wet tho.


And now I've been reading up on head gasket signs, when I changed the thermostat and I began to fool the system back up the radiator was spewing fluid. I didn't think much of it as I turned off the engine and when I restarted it to bleed the system it didn't do it again.

 

Headed to AutoZone to get the block tester liquid.

 

Did the wet plug smell like fuel or coolant? Also is the hose still on the bottom of the reservoir cap? Did you flush the system? May have a restricted heater core causing the blowing heat problem. Did it do that before you replaced everything?

 

I couldn't really tell. I want to say yes.
Yes the hose is there.
Yes I flushed.
It has been doing that since winter. The heater has been doing that since winter. So yes.

Also, hit the block tester from AutoZone and I was unable to get the blue liquid to turn yellow.

 

So I mention the plug that was wet. If I check the plug right after I turn off the engine it is dry. But I wait a little bit of time to check it it will be wet and I can see liquid sitting on the cylinder. I def believe it to be the head gasket.