LS - 1st and 2nd Gen (1990-2000) Discussion topics related to the 1990 - 2000 Lexus LS400

coolant system issues. bizzare to me

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Old 07-11-10, 01:44 PM
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Dereke
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Default coolant system issues. bizzare to me

so driving back from the gas station yesterday (about a 1.5 mile drive) my car started sputtering. i pulled over and shut it off. i popped the hood and the front of the motor was soaked with coolant, including the plug wires and caps (leading to the motor misfiring). i found a crack in the plastic thermostat housing so i replaced it and refilled the coolant. today out driving, i got about 4 miles away from home and it did it again. motor soaked and spark flooded. i stopped again and it took me about 2 hours to get back home.. drying off plug wires and topping off fluid every 3 blocks. now that i am home, i am stumped. just idling i dont see any leaks and once it sprays, there is too much coolant to see where it came from..

this is my only car, can someone please help?
Old 07-11-10, 02:31 PM
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SRV1
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You need to get the cooling system pressure tested to see where the leak is coming from or you can clean the engine off and let it dry then fill the cooling system up and let the car run to see where the leak is coming from.

James
Old 07-11-10, 03:34 PM
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did you replace the thermostat itself? it could be so blocked with something that it's causing high pressure in front of it and making the gasket/fipg fail.
Old 07-11-10, 06:30 PM
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every time the thermostat housing is removed you need to change the thermostat gasket. do not use sealant on it.
Old 07-13-10, 09:58 AM
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Dereke
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well the housing isnt leaking. the belts are coming out of the lower cover wet, so im thinking its the water pump.

ordered new pump and belt. going to tackle the job tomorrow.
Old 07-13-10, 01:43 PM
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Lori11
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I just had this problem, it was/is the bypass hose........
Old 07-13-10, 02:11 PM
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Dereke
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how did you fix the bypass hose?
what is a bypass hose?
where is the bypass hose?
Old 07-14-10, 01:07 PM
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BrittonJ85
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I ran into the same problem in which my housing cracked. I thought it was because the housing was old but nope... Come to find out that my water pumped had seized. Make sure you check you're water pump.
Old 07-19-10, 09:14 AM
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Dereke
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i finally tackled this problem over the weekend..

put car in air, topped off coolant and started the car.

noticed what i thought was a timing belt idler pulley sticking and seizing up. saw it was not only screeching but also glazing the timing belt. i tapped it with a hammer and it freed up but still didnt sound healthy. then the car started to over heat and the belt started to fling water everywhere. so.. there is a leak behind the timing cover somewhere..

went to autozone and got the timing belt and water pump. couldnt find what i thought was the idler pulley, till i opened the water pump box and realized it was the water pump pulley that was the one seized.

spent about 3 hours pulling the motor apart to get to the pump and belt and called it a day.

sunday morning i finished it all up. put it back together and went to put the radiator back in when i noticed that it was literally caked solid with dirt and weeds. took about 45 min to clean the rad out.

slid the rad in and topped the coolant off.

thing runs like a champ now. temp gauge is rock solid even in our 100+* heat and ac on full blast (before it would fluctuate all over the place in slow or stop n go traffic, even with ac off). car also seems to be running better all the way around, but i also took the time to clean off the crank angle sensor since it had road grit and goo all over it.

the replacement took a lot of time to do but it was def worth it. feels like a whole new car and is fun to cruise again.
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