Ls400 overheats when idle
#17
Lexus Champion
did you try getting the car fully warmed up?
if it still won't budge,
● make sure the blades turn smoothly
● check 30A RDI FAN fuse for continuity
● verify that the fan motor itself is good, using a heavy jumper with alligator clips, apply +12V power from battery to blue wire on connector at fan motor and connect black wire from motor to battery negative and verify that motor spins up
this circuit is pretty simple, it will be no problem for us to get to the bottom of it
if it still won't budge,
● make sure the blades turn smoothly
● check 30A RDI FAN fuse for continuity
● verify that the fan motor itself is good, using a heavy jumper with alligator clips, apply +12V power from battery to blue wire on connector at fan motor and connect black wire from motor to battery negative and verify that motor spins up
this circuit is pretty simple, it will be no problem for us to get to the bottom of it
#18
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I tried to bleed the cooling system today, i replaced the radiator cap with a dealer one. The resivor had quite a few bubbles coming out, but now the overheating seems to be worse. When i am driving the temperature will spike up rather quickly, then go back to about half, it almost reached the red zone once. Could this be caused by not using toyota red coolant?
#19
Lexus Champion
not using Toyota red coolant mainly has the effect of clogging the radiator over time - if you want your radiator to last 250K or more miles, use Toyota red coolant!
the choice of coolant brand and type does not affect the temperature the car runs at, as long as you are using a 50/50 mix of coolant and distilled water
have you checked again whether the electric fan is running once it gets over half way?
if electric fan is not running when it temp is over half way on the gauge, you have to find and fix the electric fan issue before even worrying about other causes!
how many miles this car again?
the choice of coolant brand and type does not affect the temperature the car runs at, as long as you are using a 50/50 mix of coolant and distilled water
have you checked again whether the electric fan is running once it gets over half way?
if electric fan is not running when it temp is over half way on the gauge, you have to find and fix the electric fan issue before even worrying about other causes!
how many miles this car again?
#20
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178k miles. Here is whats happening now- when the car is idle the temperature goes to the middle of the Gauge. When i get up to 45 mph the temperature rises very quickly, all the way to the red zone, then it wont go back down unless i stop the car. The fan doesnt come on. I think i messed something up when trying to bleed the cooling system? It wasnt doing this before.
When i put the coolant in i was using the resivor, should i use the hole on top of the thermostat as well?
When i put the coolant in i was using the resivor, should i use the hole on top of the thermostat as well?
#21
Lexus Champion
yes - you must use the fill bolt - a large bolt behind the thermostat which is pointed straight down at the ground - after it is full there, run the car with the heat on max and squeeze the large radiator hoses and burp out any air - replace the bolt when you can go awhile and cannot get it to take more coolant
also, even before you do that, you need to open the thermostat housing and rotate the thermostat such that the jiggle valve is at the 12 o'clock position, so that the system will bleed correctly. - a new thermostat gasket would be a good idea (a couple of dollars)
and we have to determine why the fan is not working, so check the fuse mentioned earlier as well as the other tests I outlined
also, even before you do that, you need to open the thermostat housing and rotate the thermostat such that the jiggle valve is at the 12 o'clock position, so that the system will bleed correctly. - a new thermostat gasket would be a good idea (a couple of dollars)
and we have to determine why the fan is not working, so check the fuse mentioned earlier as well as the other tests I outlined
#23
Lexus Champion
#25
Lexus Champion
I don't have JDM part numbers, not sure you even have a sensor at bottom corner of the radiator
but here are the LS400 part numbers:
● 1 wire sensor for gauge - 83420-20040
● The temperature sender at the bottom of the radiator - 89428-33010
but here are the LS400 part numbers:
● 1 wire sensor for gauge - 83420-20040
● The temperature sender at the bottom of the radiator - 89428-33010
#26
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I cannot get that fill bolt off for the life of me, it wont come off. I took the thermostat housing and thermostat out and filled it up through there, it was prrtty low on coolant. Now running the heater and squeezing the rad tubes, the heat is working good now at idle. I also made sure the jigger was at 12 o'clock.
Last edited by Comptia; 02-07-14 at 01:10 PM.
#28
Lexus Champion
the fill bolt will come off, you are not using the right tool - you need a high quality six-point socket of the exact size, either 14mm or 17mm - I forget, - and you need a breaker bar (aka flex handle), it looks like a ratchet but without the ratchet head, and possibly a short extension
you can not bleed the system properly without opening the fill bolt
tell me what store is closest between Lowes, Home Depot, and Sears and I will list you out the tools to buy
don't worry about the squeaking right now, it will be fine
you can not bleed the system properly without opening the fill bolt
tell me what store is closest between Lowes, Home Depot, and Sears and I will list you out the tools to buy
don't worry about the squeaking right now, it will be fine
Last edited by LScowboyLS; 02-07-14 at 02:59 PM.