i have a 1992 lexus es 300......i have had 2 thermostats put in it...a brand new radiator and the only thing i havnt replaced is the water pump, but i dont want to buy that if i dont need it...when i start the car cold it doesnt overheat automatically it takes about ten minutes or it happens faster when i put a load on it....and when it starts overheating the overflow tank will boil and steam will be blowing out of the top ...im going to take the top radiator hose off tomorrow and see if i am getting any flow from the water pump..i am thinking cracked head or gasket....its a 24 valve dual overhead cam 3vz-fe engine...if any one has any advise what i should do i would greatly appreciate it...

 

That kind of sounds like a head gasket problem. Being on the Legend forums often I know a lot about them. The 2nd gen Legends have these same symptoms when the head gaskets are bad. With the coolant overflow tank pressurizing and overflowing I can almost guarantee that it is caused by the head gaskets.

What color is the exhaust and does it have a sweet smell to it? Does the oil filler cap have any kind of strange residue on it? Check if there is any coolant in your oil.

How many miles on it?

 

it has approximatly 120,000 miles...there is no steam in the exhaust but there is kind of a sweet smell to it....no residue around the oil cap either..but oil does seem kind of thin....if it is a head gasket is there any way to pinpoint which head it is with out doing a compression test..i dont have the gauges and i dont know if i can afford them and i dont really want to pull the front head off too find out that i pulled the wrong head...thanks alot for the help

 

and if anything maybe the pressurized combustion gases are forcing itself in the cooling system?

 

They make tests for that, as exhaust gasses mix with the coolant it forms substances that react with whatever it is they use.

There's a cylinder leakdown test, when they pressurize the cylinder with air and measure losses. A compression test where you hook up a gauge to a cylinder and crank it. They can also pressure test the cooling system, or use a sniffing machine to detect hydrocarbon levels, and a test for CO in the coolant. I think these tests would run about $50.

Harborfreight.com has compression testers for $10 or something. You might have a store in your area. That would probably be the cheapest/effective way if you do it yourself.

 

ya there is a harbor freight in my area i didnt even think about that..ill probably try that tomorro thanks for the help..ill try to let you know the results

 

Also, it might be your cooling fan. You can test it by jumping a couple terminals of the diagnostics port. The fan will spin up to full speed. Don't remember which terminals, but see if your cooling fan is working right.
I'm not so sure, but it seems like a bad HG would be more symptomatic if it's overheating that badly.