how to bleed the cooling system
12-22-11, 08:37 PM
#1
how to bleed the cooling system
i've searched and have not found a definite or clear answer to my question. i need to bleed my cooling system b/c:
1) my car slightly overheats in traffic, when rev'd above 2k the temp will go back to normal
2) my heater only works when i rev the car the same way
so know i have air in my coolant lines but i have not seen how to get the air out other than maxing out the heater, getting the car into operating temp, and rev the car at 1.5k to 2k for 5-10mins. is this the only way to do this or is there another way?
side note: this is happening after my timing belt/water pump job. i did replace the thermostat, placing the air port at the 12 o'clock position. i did NOT however drain the coolant from the block as indicated here:
http://www.lexls.com/tutorials/cooling/coolant.html
i simply drained from the radiator. i know i still have some old coolant in there but i did refill using the method in the tutorial. nothing is burning off and my reservoir is still full. the car currently has 1 gal pure toyota red coolant, and 3/4gal of distilled water (on top of the leftover old coolant in the block cavities). any insight is much appreciated!
1) my car slightly overheats in traffic, when rev'd above 2k the temp will go back to normal
2) my heater only works when i rev the car the same way
so know i have air in my coolant lines but i have not seen how to get the air out other than maxing out the heater, getting the car into operating temp, and rev the car at 1.5k to 2k for 5-10mins. is this the only way to do this or is there another way?
side note: this is happening after my timing belt/water pump job. i did replace the thermostat, placing the air port at the 12 o'clock position. i did NOT however drain the coolant from the block as indicated here:
http://www.lexls.com/tutorials/cooling/coolant.html
i simply drained from the radiator. i know i still have some old coolant in there but i did refill using the method in the tutorial. nothing is burning off and my reservoir is still full. the car currently has 1 gal pure toyota red coolant, and 3/4gal of distilled water (on top of the leftover old coolant in the block cavities). any insight is much appreciated!
12-22-11, 09:11 PM
#2
search harder 
with an empty/cold engine, you'll fill the reservoir, then completely fill the system through the bleed point on the inlet housing. then start the car with the heater on max temp and high Fan setting, and continue to add water as needed until the car is at op. temp. then, making sure the water level is around the level of the bleed plug, tighten the bleed point back up, and make sure the reservoir is full.
with an empty/cold engine, you'll fill the reservoir, then completely fill the system through the bleed point on the inlet housing. then start the car with the heater on max temp and high Fan setting, and continue to add water as needed until the car is at op. temp. then, making sure the water level is around the level of the bleed plug, tighten the bleed point back up, and make sure the reservoir is full.
12-23-11, 01:34 AM
#4
thanks guys and yes i may have been using the wrong key words.
i didn't know i could keep the inlet hole open while the engine was on. i thought it was just for initial fills then add at the reservoir as necessary. on my car the coolant is actually seeping out of the inlet hole, which means i should replace that washer. it looked questionable when i reinstalled it during the t-belt job. you think the leak is adding air into the system?
i'll replace the crush washer then refill from there. thanks again!
i didn't know i could keep the inlet hole open while the engine was on. i thought it was just for initial fills then add at the reservoir as necessary. on my car the coolant is actually seeping out of the inlet hole, which means i should replace that washer. it looked questionable when i reinstalled it during the t-belt job. you think the leak is adding air into the system?
i'll replace the crush washer then refill from there. thanks again!
12-23-11, 01:38 AM
#5
https://www.clublexus.com/forums/ls4...der-valve.html
01-18-12, 01:32 PM
#7
i just wanted to do a brief update for future folks needing this info, but it's just a reiteration what you guys told me anyway.
i got the car running well. bleeding the system was all at that it took, which is what everyone here told me haha. here is what i did for FYI purposes:
- followed PD's instruction to fill through the inlet while the car was on and heater at max temp
- did this for 10 mins while holding the revs at 1.5k - 2k
- replaced the crush washer on the filler neck, then closed it off
- refilled the reservoir afterwards
what i noticed was when i turned off the car while having the inlet open, a cup of coolant was displaced out into my funnel. that scared me so i restarted the car and the coolant level when down again. i added a bit more then closed it off while the car was on. the car runs normally now with a fully functioning heater.
thanks again to all who helped!
i got the car running well. bleeding the system was all at that it took, which is what everyone here told me haha. here is what i did for FYI purposes:
- followed PD's instruction to fill through the inlet while the car was on and heater at max temp
- did this for 10 mins while holding the revs at 1.5k - 2k
- replaced the crush washer on the filler neck, then closed it off
- refilled the reservoir afterwards
what i noticed was when i turned off the car while having the inlet open, a cup of coolant was displaced out into my funnel. that scared me so i restarted the car and the coolant level when down again. i added a bit more then closed it off while the car was on. the car runs normally now with a fully functioning heater.
thanks again to all who helped!
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06-30-13, 03:49 PM
#8
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Hi guys I have a 95 ls400 that starts overheating at idle and with the a/c on but when I start going it goes back to normal with the a/c off but with it on it heats up. I tried to purge air from the system but I dont know if coolant is supposed to come out of the coolant tank when reving. Any help would be appreciated
06-30-13, 08:34 PM
#9
Lexus Champion
make sure the jiggler hole on the thermostat is in the 12 o'clock position (this insures proper bleeding)
if you have done that and then fill at the Fill Bolt above the thermostat housing, and also fill the overflow to the max mark, the system will self-bleed over the next day or two of driving and you can just top up the reservoir a time or two as you see the level go down without all of the rigamarole!
best to have a real Toyota radiator cap in tip top condition (I like a new one) for this to happen successfully
if you have done that and then fill at the Fill Bolt above the thermostat housing, and also fill the overflow to the max mark, the system will self-bleed over the next day or two of driving and you can just top up the reservoir a time or two as you see the level go down without all of the rigamarole!
best to have a real Toyota radiator cap in tip top condition (I like a new one) for this to happen successfully
Last edited by LScowboyLS; 06-30-13 at 08:51 PM.
07-01-13, 10:53 AM
#10
Hi guys I have a 95 ls400 that starts overheating at idle and with the a/c on but when I start going it goes back to normal with the a/c off but with it on it heats up. I tried to purge air from the system but I dont know if coolant is supposed to come out of the coolant tank when reving. Any help would be appreciated
it could also be that your fans are compromised as well. you have a belt driven fan, as well as an electric fan that should turn on at a certain temperature. check that both fans are working. the electric fan is directly behind the front lower grill. temporarily bypass the connector, add power, and see if it spins freely. then also check the relay, then lastly the sensor.
electric fan
07-01-13, 12:18 PM
#11
Hi guys I have a 95 ls400 that starts overheating at idle and with the a/c on but when I start going it goes back to normal with the a/c off but with it on it heats up. I tried to purge air from the system but I dont know if coolant is supposed to come out of the coolant tank when reving. Any help would be appreciated
11-18-13, 06:27 AM
#12
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i've searched and have not found a definite or clear answer to my question. i need to bleed my cooling system b/c:
1) my car slightly overheats in traffic, when rev'd above 2k the temp will go back to normal
2) my heater only works when i rev the car the same way
so know i have air in my coolant lines but i have not seen how to get the air out other than maxing out the heater, getting the car into operating temp, and rev the car at 1.5k to 2k for 5-10mins. is this the only way to do this or is there another way?
side note: this is happening after my timing belt/water pump job. i did replace the thermostat, placing the air port at the 12 o'clock position. i did NOT however drain the coolant from the block as indicated here:
http://www.lexls.com/tutorials/cooling/coolant.html
i simply drained from the radiator. i know i still have some old coolant in there but i did refill using the method in the tutorial. nothing is burning off and my reservoir is still full. the car currently has 1 gal pure toyota red coolant, and 3/4gal of distilled water (on top of the leftover old coolant in the block cavities). any insight is much appreciated!
1) my car slightly overheats in traffic, when rev'd above 2k the temp will go back to normal
2) my heater only works when i rev the car the same way
so know i have air in my coolant lines but i have not seen how to get the air out other than maxing out the heater, getting the car into operating temp, and rev the car at 1.5k to 2k for 5-10mins. is this the only way to do this or is there another way?
side note: this is happening after my timing belt/water pump job. i did replace the thermostat, placing the air port at the 12 o'clock position. i did NOT however drain the coolant from the block as indicated here:
http://www.lexls.com/tutorials/cooling/coolant.html
i simply drained from the radiator. i know i still have some old coolant in there but i did refill using the method in the tutorial. nothing is burning off and my reservoir is still full. the car currently has 1 gal pure toyota red coolant, and 3/4gal of distilled water (on top of the leftover old coolant in the block cavities). any insight is much appreciated!
11-18-13, 12:28 PM
#13
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08-15-15, 10:11 AM
#14
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I know I'm bumping an old thread, but hey, at least I searched. I tried the method above to bleed the system in my '99 but I still believe I have air somewhere in the system. The temp will begin to rise in traffic, but goes back to normal after some driving or turning the heater on. I've taken it to the shop and they said my cooling system is in working order so I don't think I have any failing companies, just an air pocket. So what's the absolute best method to bleed the system in this car? If I need to pick up a spill free funnel I will.