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Lexus ls400 overheating issue

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Old Jul 1, 2018 | 04:10 PM
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Default Lexus ls400 overheating issue

Hey new to the clublexus and just wondering how many have had issues with overheating in a 1997 ls400.
The car was perfect untill december last when i had to replace the crankshaft oil seal.
after i replaced everything it was driving perfect again. I then parked the car for a few months and now its overheating.
strangly the way it is over heating is mind boggling . On idle it is perfect , when you drive around 40mph it will rise slowly untill you slow down again it will drop back to normal.
I have checked theromostat and the usual heating issues.
womdering if anyone knowd if they hold air pockets in the heayimg systems and if there is a procdure to bleed these systems.
there is very little of these in ireland so any help would be greatly apperacted
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Old Jul 1, 2018 | 05:19 PM
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Welcome to Club Lexus.

May need to be burped though suspect that there is something else going on. How many km/miles on car and is this the original radiator?
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Old Jul 2, 2018 | 02:55 AM
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Thanks for reply
there is 160k miles and its the orignal rad as far as i can tell indeed
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Old Jul 2, 2018 | 09:20 AM
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Since your car sat for a period of time it sounds like sediment settled in the radiator and is blocking the flow. I'd start with having the cooling system flushed, refilled and bled. If that doesn't fix the issue then you're probably looking at a new radiator.
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Old Jul 2, 2018 | 02:02 PM
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you need to rebleed. i did rad hoses on my 97 first thing and it did the same thing. i was also about a half gallon low on coolant
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Old Jul 2, 2018 | 04:01 PM
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Thanks for all the help guys i gona try some of these tomorrow . Is there any procdure to bleed the system.or am i right im saying its a self bleed i cant seem.to find amy bleed screw
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Old Jul 2, 2018 | 05:09 PM
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It helps if you can park with the front end slightly higher than the rear. This raises the high point of the system and helps any trapped air rise to the top.

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Old Jul 2, 2018 | 07:29 PM
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Thats perfect thanks ill do that tomorrow and post results. I really apperacite the help and info. Hopefully its a as easy a bleed.
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Old Jul 2, 2018 | 11:52 PM
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Originally Posted by Dipper30
Thanks for all the help guys i gona try some of these tomorrow . Is there any procdure to bleed the system.or am i right im saying its a self bleed i cant seem.to find amy bleed screw
There should be a sticker on the overflow bottle telling you exactly how to do it. Mine, as i'm thinking yours is, was missing so I had nothing to go by.

You basically fill the coolant through the 17mm bolt in the front center of the engine. Remove it, start the engine, and let it idle and add coolant to this bolt hole until it starts running out and is full. Replace the 17mm bolt. Run the engine with the overflow cap off and tank full at 2500RPM for 5 minutes to get it nice and warm. Shut the engine off and let it cool down. As the engine cools, it'll suck coolant from the overflow bottle. Replace the cap when the engine is cool.
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Old Jul 3, 2018 | 11:57 AM
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I bookmark so many of these threads.....thank you people.
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Old Jul 3, 2018 | 11:18 PM
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Default Fan clutch most likely

Originally Posted by Dipper30
Hey new to the clublexus and just wondering how many have had issues with overheating in a 1997 ls400.
The car was perfect untill december last when i had to replace the crankshaft oil seal.
after i replaced everything it was driving perfect again. I then parked the car for a few months and now its overheating.
strangly the way it is over heating is mind boggling . On idle it is perfect , when you drive around 40mph it will rise slowly untill you slow down again it will drop back to normal.
I have checked theromostat and the usual heating issues.
womdering if anyone knowd if they hold air pockets in the heayimg systems and if there is a procdure to bleed these systems.
there is very little of these in ireland so any help would be greatly apperacted
My acted like that i replace the fan clutch and flas the coolant
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Old Jul 5, 2018 | 09:03 AM
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Get the front end up about a foot higher than the rear to burp it. Or you could place a level on the intake and see when it is actually elevated. Burping is the slang people use meaning to filled the coolant and get air pockets out. Follow the procedure, but do it with the front end higher than the engine. Someone on here drove theirs up on ramps and another guy drove it up on the sidewalk.
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Old Jul 14, 2018 | 08:45 AM
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Thanks everyone for all the help and pointers it worked a treat very greatfull to all
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