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How to change thermostat in KZJ90?

kzj90nz

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Hi all,

I'm in the middle of battling the overheating issues that have become infamous with the 1KZ-TE . I've pulled out the old radiator (new one just about ready to go back in), fitted new hoses and have refilled the fan hub with silicon oil - thanks for your advice so far!

The new coolant I put in two months ago had gone brown - there must be a lot of crud in the system and I hope the new radiator will sort it out!

I'm still trying to work out how to change the thermostat?

I've gone for the standard Toyota 76 degree item that comes highly recommended by a number of members on here.

Following Raven's previous advice, if I follow the bottom heater hose upwards towards the block there is what I suspect is the thermostat housing.

Anyone have a picture of what I should be looking at and have any advice for gaining access?

Do you need to remove the intercooler or battery to remove the housing and comfortably swap the thermostat?

Once the housing is off, is the thermostat held in place by anything in particular or will it just pull out?

There must be an easy way for the 1KZ-TE which I don't know about!
 
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Chris

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The housing is pretty obvious. It on the slide of the block connected to the bottom hose. It's a domed thing. One thing I'd suggest before pulling that off is to get a new O ring seal to go with the thermostat. It tends to go a bit baggy and that makes it difficult to put back in. The stat is just put in the hole. There's no clips or anything. The stat also has a small hole in it and a little toggle. This is part of the fail safe mechanism and it's supposed to be oriented the right way. However, in a useless bit of guidance, I can't recall the argument that says which way up it should go. I used to put it at the bottom so the block would drain fully when I took the hose off. But have a feeling it goes at the top to allow air to bleed.

I'm sure we'll debate this one shortly.

Seem to remember that I used to change my from underneath.
 
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Shayne

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Its not an easy thing to photograph but you can get your hand (or a spanner) on it from above . I think i got 2 nuts from above and the last from beneath . Your oil dipstick tube is bolted to the stat housing so follow the dipstick down 3 inches and your there .

Drain coolant first . The stat sits in place like a gasket so it will fall out when the housing is removed , i managed to catch mine so copied the which way up position when i put the new one in though i'm buggered if i can remember where the toggle Chris mentions went ?

My mrT stat came with a replacement o-ring but the old one could have been used again .

That's it really :think: there may be another nut securing the housing lower down where the hose meets but its all very obvious and not difficult at all .
 
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kzj90nz

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Yeah I thought I could see the top of the thermostat housing behind/below the dip stick - it's a bit of a pain to get to.

It looks like a regular housing but with a longer tail. I take it that it's possible to only remove the upper part of the housing instead of taking out the whole component - right down to where the rubber hose slides on?

From memory did you guys have to remove the battery or any of the piping to get to the thermostat?

While I've got the radiator out, any service tips for the AC condenser? Was just going to give it a wash with the hose.

Many thanks!
 

BobMurphy

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Here we go again (I have also put these on "The other side" :eusa-whistle:):

The housing is simple enough but on an 'Auto' the gearbox cooling pipes can get in the way, also I think the engine dipstick tube shares one of the bolts.


DSCN5864.jpg





DSCN5867.jpg




I put the 'toggle' at the top - to let the air out (that may not be what Mr T intended :think:).

Bob.
 

kzj90nz

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Bob - you bloody legend! Saving the day once again :)

I've got the auto which as you say is a bit more fiddly - what did you remove to get that sort of access to the bolts? Just the battery?
 
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Chris

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Ahh yes, it's that sneaky damn bolt on the elbow that catches most people out. Hours of wiggling only to find that little devil hiding.
 

silvercruiser

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Just be thankful your not doing the same job on the 120:icon-evil:. its pretty straight forward as others have already said.

I also put the toggle to the top with the same thoughts as Bob, to allow any trapped air out of the system.
 

BobMurphy

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What did you remove to get that sort of access to the bolts? Just the battery?

Its a few years since I last had it apart (where does the time go ?) but I seem to recall removing the battery and the sump guard. Access from top and bottom helps.

Bob.
 

kzj90nz

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Thanks guys - managed to do it by removing the battery. Just a heads up that the dip stick and ATF feeds are a bit of a pain to navigate for those with an auto. Old thermostat was completely stuffed - with a new thermostat and radiator the truck is now running better than ever.

PS: Don't be tempted to really tighten up the housing bolts - I ended up breaking a bolt!
 

Animal Mother

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Just be thankful your not doing the same job on the 120:icon-evil:. its pretty straight forward as others have already said.

I also put the toggle to the top with the same thoughts as Bob, to allow any trapped air out of the system.

@silvercruiser I'm about to do it on my 120. Any tips? Why is it so difficult?
 
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