Cooling the 1KZ-TE motor:

[Shayne]

I would pull the new stat to check its working , coolant is not circulating so if not the stat at fault there's blockage somewhere so you might get lucky removing and flushing the radiator , and of course the system as well .

There's a tiny drain plug rarely found or used on the right hand side of the block for coolant , I undid it when i drained mine and was unimpressed but perhaps its there in sympathy to some sort of catch pit ?

Oh hang on that was on the 1kz-te , same block ? worth a look anyway .

 

[Tommogen3]

hmm, its like the thermostat does not open in time. pressure builds up and pushes the seal out. thats why the hose is not blowing. the pressure is building up at the stat. im going to have it looked at tomorrow. then ill probably take it all off again and see if i did anything wrong. thanks guys

 

[Tommogen3]

I would pull the new stat to check its working , coolant is not circulating so if not the stat at fault there's blockage somewhere so you might get lucky removing and flushing the radiator , and of course the system as well .

There's a tiny drain plug rarely found or used on the right hand side of the block for coolant , I undid it when i drained mine and was unimpressed but perhaps its there in sympathy to some sort of catch pit ?

Oh hang on that was on the 1kz-te , same block ? worth a look anyway .

Hey, i did actually put the stat in a cup of boiling water and it opened on. I didn't really flush the engine well. i guess there could of been alot of air in there. do you have a picture of this drainage point? i could not find it earlier.

 

[StarCruiser]

hmm, its like the thermostat does not open in time. pressure builds up and pushes the seal out. thats why the hose is not blowing. the pressure is building up at the stat. im going to have it looked at tomorrow. then ill probably take it all off again and see if i did anything wrong. thanks guys

Is it a genuine stat? I’ve had aftermarket stats be the wrong shape and foul the housing when fitted causing leaks on my Shogun. Not sure if it’s possible on this one.

 

[Shayne]

I don't sorry you can't see the bugger but iirc its a lone brass nut which seemingly serves no purpose , if you feel it you know it shouldn't be there kind of thing .

 

[Tommogen3]

Is it a genuine stat? I’ve had aftermarket stats be the wrong shape and foul the housing when fitted causing leaks on my Shogun. Not sure if it’s possible on this one.

its a roughtracks cheaper one. i might just order the other one now and be one with it.

 

[Beau]

hmm, its like the thermostat does not open in time. pressure builds up and pushes the seal out. thats why the hose is not blowing. the pressure is building up at the stat. im going to have it looked at tomorrow. then ill probably take it all off again and see if i did anything wrong. thanks guys

The coolant circuit is open so it doesn't matter where the pressure enters, the entire circuit is running under the same pressure. These systems get fed from the bottom, through the block, then head and back out on the top side of the rad.

 

[Shayne]

But water expands when heated hence we have an overflow bottle , if the stat don't open whats in the rad just gets hotter and hotter .

Pulling the hose off the bottom of the rad just to see what comes out costs nothing you could fill it up with water and take it for a test drive 5 minutes later .

I've spent thousands at Roughtrax and never been disappointed , even when i once messed something up myself the were very quick to send me replacement parts and get me back on the road , without charge i might add though i did phone up and pay once i worked out it was my fault . Give them a call .

Here's a thought , heater pipes take up a lot of coolant but don't actually fill after a flush so leave it ticking over until the heater is blowing hot and then check fluid level in the rad .

 

[StarCruiser]

There may be a point here, have you got the correct radiator cap on there? That should deal with any over pressure. That coupled with what Beau said about the thermostat housing is where I’d be looking.
As Shayne says, probably worth a call to Roughtrax to get them to check dimensions of the thermostat against a genuine one.

 

[Tommogen3]

yea i canceled the part. im sure its fine. i believe, that the coolant that was in there was just rubbish rusty tap water and that boils at a lower temp than Toyotas genuine coolant. i think with a propper flush (after i find the bleed nipple for the coolant) and the right coolant it should get going..

just a reminder theres no pressure getting to the radiator. it simply runs out the side of the thermostat in the engine block. once it gets to temp.

 

[StarCruiser]

just a reminder theres no pressure getting to the radiator. it simply runs out the side of the thermostat in the engine block. once it gets to temp.

As Beau rightly pointed out, though the flow is initially prevented from going to the radiator by the thermostat, the pressure on the system will be the same throughout so what you have is a thermostat housing that isn’t sealing for one reason or another. If you suspect, as you’ve said, that there is too much pressure, it is the radiator cap that would normally release this pressure, dumping into the expansion bottle. Even if you substituted the thermostat for a metal disk, this would be the case because the return hose into the bottom of the engine is open to the radiator and the pressure would build that way. If it didn’t you would have a massive build up of pressure waiting for an excuse to explode. Unsurprisingly this isn’t allowed. Unless the wrong pressure radiator cap is used then the pressure should not be above what is permissible.

You need to find out why the leak is happening. Is it because someone has overtightened the housing in the past and deformed it? Don’t know if that’s possible but there will be a reason. Wrong bolts used that bottom out instead of tightening down on the housing perhaps? Go find why.

 

[Tommogen3]

As Beau rightly pointed out, though the flow is initially prevented from going to the radiator by the thermostat, the pressure on the system will be the same throughout so what you have is a thermostat housing that isn’t sealing for one reason or another. If you suspect, as you’ve said, that there is too much pressure, it is the radiator cap that would normally release this pressure, dumping into the expansion bottle. Even if you substituted the thermostat for a metal disk, this would be the case because the return hose into the bottom of the engine is open to the radiator and the pressure would build that way. If it didn’t you would have a massive build up of pressure waiting for an excuse to explode. Unsurprisingly this isn’t allowed. Unless the wrong pressure radiator cap is used then the pressure should not be above what is permissible.

You need to find out why the leak is happening. Is it because someone has overtightened the housing in the past and deformed it? Don’t know if that’s possible but there will be a reason. Wrong bolts used that bottom out instead of tightening down on the housing perhaps? Go find why.

i need to check the rad cap, even though it has never given me any trouble before it could be part of the problem.
thanks, i will have another go tomorrow and let you know how i get on. thanks for your advice

 

[Xena]

[QUOTE=" do you have a picture of this drainage point? i could not find it earlier.[/QUOTE]

On the block under the intake manifold area just beside the oil cooler. Hope it helps

 

[Xena]

You need to find out why the leak is happening. Is it because someone has overtightened the housing in the past and deformed it? Don’t know if that’s possible but there will be a reason. Wrong bolts used that bottom out instead of tightening down on the housing perhaps? Go find why. [/QUOTE]

Maybe Mating surface has deformed?
Thermostat housing is cast alloy so can be eaten away by corrosion?
Gasket not sealing properly? (try silicone gasket maker on the metal mating surface)
Cracked thermostat housing?
Fastening bolts not torqued properly or maybe loose thread/crossed thread/bottomed out?

In my own experience with over pressure, the ones that give out first are the rad cap (the spring is pressure rated and so spills out into the coolant recovery bottle), the hose blows out, the radiator top/bottom crimp (if rad has plastic top and bottom)

 

[Tommogen3]

just checked the radiator cap. it appears to be a 0.9 bar 13 psi one. which i think is correct for a gen 3. ill get some coolant and re seat the thermostat later.

 

[Tommogen3]

ok we found the culprit. this tube on top was rusty and appears to of been repaired before I got the car. does anyone know the part number for this? looks like the bolts have rusted in place too. :/

 

[diggerdave]

Phew, that must be a relief.

Part nos can be found here but make sure you search for your specific model
http://www.japan-parts.eu/toyota/eu.../kzj90r-gjmntw/3_781540_003_/tool-engine-fuel

 

[Tommogen3]

part number is t87208-35260

https://toyota-general.epc-data.com/land_cruiser_prado/kzj95r/8288/electric/8716/87208B/
the part is 199.62 pounds each. I think I'll repair the pipe

 

[StarCruiser]

part number is t87208-35260

https://toyota-general.epc-data.com/land_cruiser_prado/kzj95r/8288/electric/8716/87208B/
the part is 199.62 pounds each. I think I'll repair the pipe

You can see what happened to the previous repair. In that location it looks like a whole heap of pain if you ask me. Have you looked on Amayama?

 

[Shayne]

Something of nothing , if you can get it off in some semblance of its original dimensions take it to a stainless place and they will probably knock one up during tea break for a tenner .