PO bypassed heater control valve and always empty overflow jug? (1 Viewer)

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legends. i have a 97 LX 450 with 225K that i bought with a bypassed heater control valve. i fixed this. at some point i noticed the overflow jug was always empty. hot or cold it was empty. someone on here noticed i did not have an OEM radiator cap so i finally found some time and bought one a couple months ago.
anyway i finally got some time last weekend to "burp the system". i parked in a "loaner driveway" on level ground (i know there is some debate about this) and i put the heater on highest setting.
then i filled the overflow jug to full level. then i took the rad cap off filled the radiator from the bottom of the filler neck to the top of the filler neck. then i started the vehicle and let it idle.
at some point i realized that while the bottom of the filler neck looked full - if i filled to the top of the filler neck (like 2 ounce difference or something) it would suck it down and then i would refill and it would suck it down again.
anyway about a half a gallon later it seemed to stop sucking coolant down and i notice a couple splashes of coolant. so i capped it and realized i had not put the overflow tube back in the jug so coolant hit the fan splashing a little and a lot landed on the ground.
anyway, i pulled it around and parked it back on the street and in the morning i came out to a large puddle of what appeared to be coolant (slick between the fingers).
so now i am trying to figure out what i have going on. engine temps seem to stay in the normal range and i don't know i would notice anything if i didn't check the oveflow jug. the radiator itself always stays "full" at the bottom of the filler neck.
i got under it this afternoon and also took some pics. i do see some coolant drips but not sure what to make of this since i spilled a lot the other day when burping the system.
also this morning the overflow jug was full and when i got back and even now on a totally cold engine the overflow jug is empty.
is it possible the overflow jug leaks under pressure (somehow?) even though blowing air into it makes it seem like it is intact?
any helpful suggestions?
THANKS
<very late edit: i did pressure test the radiator shortly after i got it with a kit i borrowed from a local toyota tech and it seemed to be holding pressure but i guess i need to test it again...?>

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One of the legends will be along shortly but in the meantime I would suggest hosing off everywhere that you think you spilled the coolant. From that point on you will know if you have a leak or spillage. The cooling system on the land cruiser is self bleeding but, and it is a big but, the complete system must be sealed. As the system heats up, the coolant will pressurize and once the pressure exceeds the cap rating the coolant will flow into the reservoir. This is how the excess air is expelled also. As the system cool down the coolant in the reservoir is drawn back into the system.
If there is a leak anywhere in the system then the system will not pressurize therefore the radiator cap will never reach the pressure rating. First thing you need to establish is if you have a leak.
 
legends. i have a 97 LX 450 with 225K that i bought with a bypassed heater control valve. i fixed this. at some point i noticed the overflow jug was always empty. hot or cold it was empty. someone on here noticed i did not have an OEM radiator cap so i finally found some time and bought one a couple months ago.
anyway i finally got some time last weekend to "burp the system". i parked in a "loaner driveway" on level ground (i know there is some debate about this) and i put the heater on highest setting.
then i filled the overflow jug to full level. then i took the rad cap off filled the radiator from the bottom of the filler neck to the top of the filler neck. then i started the vehicle and let it idle.
at some point i realized that while the bottom of the filler neck looked full - if i filled to the top of the filler neck (like 2 ounce difference or something) it would suck it down and then i would refill and it would suck it down again.
anyway about a half a gallon later it seemed to stop sucking coolant down and i notice a couple splashes of coolant. so i capped it and realized i had not put the overflow tube back in the jug so coolant hit the fan splashing a little and a lot landed on the ground.
anyway, i pulled it around and parked it back on the street and in the morning i came out to a large puddle of what appeared to be coolant (slick between the fingers).
so now i am trying to figure out what i have going on. engine temps seem to stay in the normal range and i don't know i would notice anything if i didn't check the oveflow jug. the radiator itself always stays "full" at the bottom of the filler neck.
i got under it this afternoon and also took some pics. i do see some coolant drips but not sure what to make of this since i spilled a lot the other day when burping the system.
also this morning the overflow jug was full and when i got back and even now on a totally cold engine the overflow jug is empty.
is it possible the overflow jug leaks under pressure (somehow?) even though blowing air into it makes it seem like it is intact?
any helpful suggestions?
THANKS

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Off topic, but, my 97 LX has a different gauge cluster. 99.9% sure mine is normal. Is your vehicle a import?
 
One of the legends will be along shortly but in the meantime I would suggest hosing off everywhere that you think you spilled the coolant. From that point on you will know if you have a leak or spillage. The cooling system on the land cruiser is self bleeding but, and it is a big but, the complete system must be sealed. As the system heats up, the coolant will pressurize and once the pressure exceeds the cap rating the coolant will flow into the reservoir. This is how the excess air is expelled also. As the system cool down the coolant in the reservoir is drawn back into the system.
If there is a leak anywhere in the system then the system will not pressurize therefore the radiator cap will never reach the pressure rating. First thing you need to establish is if you have a leak.
thanks a lot IR. i forgot to mention i borrowed a pressure tester from a local toyota tech when i first got it and it seemed to hold pressure. two things about this is first he seemed to not want me to try it at the actual rating. for some reason he said not to go to the full value. and second was i actually had to shave a tiny bit off the side of the radiator flanged area to get it to fit. but since the actual cap seals from the top i don't believe this is an issue.
anyway i will hose it down.
but basically you are saying it gets hot in the engine and it expels coolant into the overflow and then it sucks it back in when it cools down?
and is that controlled by a temperature sensing valve basically was that it?
 
Off topic, but, my 97 LX has a different gauge cluster. 99.9% sure mine is normal. Is your vehicle a import?
sorry. my 98 tacoma puked oil in the street right in front of the land cruiser on the sand day so i am also over on a tacoma forum. i removed that since it was my taco...
 
t
Yep..that just about covers it.
THANKS. so basically the overflow is never under pressure. and if you blow into a cleaned out overflow jug and it doesn't leak it is likely good.
do you know what the deal is with the rear seat heater? coolant flows through it so the coolant sometimes leaks there?
 
Is the overflow valve/cap oriented in the correct direction?


Btw, your post is super tough to follow.
sorry MoJ. i've been trying things and i half understand the system.
basically my overflow jig is always empty. i fill it up. a day later or whatever and it is empty.
so i filled it up and tried to burp the system with the idea air could be in the system of something.
and it seems to have puked coolant.
so i am starting to think that somewhere at the rear heater whatever it is leaking. it leaks under pressure enough to not keep enough cooling in the system to refill the overflow when cold but not enough so that the engine temp rises drastically.
and i am remembering that the heater control valve was bypassed when i got it. which i think maybe the PO did to avoid the leak at the rear heater (?) instead of fixing it?
but shin i am not completely understanding the coping system despite trying a number of times.
 
THANKS. so basically the overflow is never under pressure. and if you blow into a cleaned out overflow jug and it doesn't leak it is likely good
Yep. The overflow is not pressurized. There is a vent to the atmosphere.
do you know what the deal is with the rear seat heater? coolant flows through it so the coolant sometimes leaks there?
The coolant that flows through the rear seat heater is part of the main cooling system. There are hard pipes from the firewall to the underside of the passenger seat and a few rubber hoses. The hard pipes are prone to rusting in the salty states and the rubber hoses degrade in all the states. The rear heater is likely the most neglected portion of the cooling system and thus most likely to leak.
 
Yep. The overflow is not pressurized. There is a vent to the atmosphere.

The coolant that flows through the rear seat heater is part of the main cooling system. There are hard pipes from the firewall to the underside of the passenger seat and a few rubber hoses. The hard pipes are prone to rusting in the salty states and the rubber hoses degrade in all the states. The rear heater is likely the most neglected portion of the cooling system and thus most likely to leak.
thanks a ton man.
i found these two and will be reading up...
oh. snap. here it is...(!)
THANK YOU
 
Get the pressure tester test the system, while under pressure look for leaks at all the hoses.
Or start truck get up to temp look for leaks.
Repair leaks, fill system bleed monitor. Move on
 
A clue I've found useful - can be seen in your pics - wherever coolant leeks out and dries - leaving whitish "water marks.
 
if the rubber hoses connecting the rear heater hardlines at the firewall are weeping or leaking, i don't see how you'd have that coolant puddle at the front of the truck. and dripping off the frame crossmember

not saying you don't have a leak back there, so certainly replace those hoses or bypass it.

i bypassed mine while searching for a faint coolant smell seemingly coming from the rear of the motor. i never found any coolant on the ground but could smell it after driving. this was AFTER replacing the PHH, radiator, and cap which were the bigger contributor to coolant loss and drips. my rear heater hardlines look good so next coolant flush when i replace the small throttle body coolant hose i'll plumb the rear heater back in with new hoses since i now know the other coolant hoses are good. it's been in the teens here all week and i'm missing the extra boost in the cabin the rear heater provides!
 
here is the bypass for the rear heater at the firewall. it's an easier job and a temporary fix for anyone needing it.
 
if the rubber hoses connecting the rear heater hardlines at the firewall are weeping or leaking, i don't see how you'd have that coolant puddle at the front of the truck. and dripping off the frame crossmember

not saying you don't have a leak back there, so certainly replace those hoses or bypass it.

i bypassed mine while searching for a faint coolant smell seemingly coming from the rear of the motor. i never found any coolant on the ground but could smell it after driving. this was AFTER replacing the PHH, radiator, and cap which were the bigger contributor to coolant loss and drips. my rear heater hardlines look good so next coolant flush when i replace the small throttle body coolant hose i'll plumb the rear heater back in with new hoses since i now know the other coolant hoses are good. it's been in the teens here all week and i'm missing the extra boost in the cabin the rear heater provides!
hey man. thanks for the eyeballs and also the thoughtful response.
is it possible that i have a leak in the rear heater lines but that when the "system" (whatever that means) does not have the full amount of fluid in it - well it doesn't leak? but when it has a full amount of fluid in it it does?
maybe that makes no sense and you are saying there would have to be a different reason for there to be that much fluid on the ground.
i admit it is kind of weird. the overflow jug will hold coolant. but it does not stay there. the radiator system will take additional fluid when "burping it". and the valve to the overflow jig appears to work both ways.
is it possible the engine cooled after i burped it? it was full of coolant? then it ducked in the amount remaining in the overflow? then it puked it out overnight? but the leak is small enough to not lose all of it?
 
Remove the overflow tank, fill it with water, wait 24 hours and see if the water level changed. Than you will know if your overflow tank is leaking or not.
 
Remove the overflow tank, fill it with water, wait 24 hours and see if the water level changed. Than you will know if your overflow tank is leaking or not.
thanks. i actually pulled it, cleaned it and looked it over and blew into it. seemed totally intact.
but i guess i could do the same as you suggest by filling it with water at night with a paper towel underneath it do you think?
 

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