Losing coolant
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From: USA
Losing coolant
2001 ls430 with 164000 miles on it. Drove the car 200 miles today in the 105 degree heat. 15 miles from the house I notice that the temp gauge is slightly higher than normal. Pull into the driveway and coolant is visible under the car. I let the car cool off and top off the resevoir and radiator, and drive it to the grocery store with no problems. Driving home I notice the temp gauge is slightly higher again pull int the driveway and antifreeze is pouring out of the overflow tube on the resevoir. Thinking back this happened once last summer as well. Any suggestions? 
Intermediate
Joined: Dec 2011
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Maybe your thermostat is bad? If it doesn't open and close properly or is stuck open it will overheat. regarding the fluid, did you fill the reservoir before it emptied? You have to make sure the system is bled correctly.
The usual cooling system maintenance. Thermostat, radiator/reservoir cap and fresh coolant. Overheating scares me so just for the sake of it, check your engine oil to make sure there is no coolant getting into the oil. Get this fixed ASAP, overheating is not good in the summer weather.
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Replaced the thermostat. Left the radiator cap off to bleed air out of the system. Let it warm up to normal operating temp. Never saw any bubbles or burping coming out of the radiator. Temps seem fine and ac blows ice cold. Radiator cap is hot so the coolant must be circulating. I guess all is well.
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Had the heat on high the whole time it was warming up. Wife drove it to the store and after she got back I noticed a pool of antifreeze under the car. Guess its still puking out of the overflow tube.
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You say you "guess" its coming from the overflow hose. Is it for sure coming from the overflow? When you were bleeding the system, did you have the car RPM's up around 2,000 for a few minutes after it hit normal operating temperature? There's not that many things that can make a car overheat. How's your oil look? Is there any milky white color on the cap? Does the car puff any white smoke or does the exhaust smell sweet at all?
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You say you "guess" its coming from the overflow hose. Is it for sure coming from the overflow? When you were bleeding the system, did you have the car RPM's up around 2,000 for a few minutes after it hit normal operating temperature? There's not that many things that can make a car overheat. How's your oil look? Is there any milky white color on the cap? Does the car puff any white smoke or does the exhaust smell sweet at all?
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Glad you're up and running. I forgot all about the cap itself. That makes perfect sense. Once the spring or gasket go bad it will spit into the overflow under pressure. It makes even more sense that it did it as soon as you stopped because the water isn't circulating any more.
Driver
Joined: Jun 2012
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From: CA
Yup, when you stop the water stops circulating and the engine block continues to get hotter and then it slowly will cool down. Try to put the car on a slant so the front is higher then the rear and that will help burp the cooling system.
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