89 FJ62 Thermostat Replacement- Should I be worried about this?

TStro

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I decided to replace my thermostat this weekend on my 89 FJ62 with 223k miles. I've got detailed service records going back to 1992. I've been running a high idle, about 950, so I decided to swap the thermostat since I have no record of it being done. I purchased all new sensors and the lower housing. I also needed to replace my AC idler pulley. It still squeals like a banshee after replacing the compressor, bearing, and new belts. I removed the fan shroud, fan, and clutch as well, taking the time to split the shroud correctly. The thermostat housing came out without too much of an issue. All bolts were intact. My big concern is the inside of the head. See the picture. Should I be concerned with all the rust? I had the coolant flushed and replaced at a local dealer less than 2000 miles ago with Toyota Red coolant. My temp gauge never showed hot, in fact, I thought the gauge always showed low temps. Should I re-flush? Is there a special sauce to flush it with other than distilled water? I searched the threads but couldn't find anything. Thanks in advance!
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HemiAlex

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You’re fine. My 3FE was way worse. It had been sitting for 13 years.

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HemiAlex

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Distilled water with radiator flush two times, refill with green concentrate and run it a few hundred miles.

Flush; refill and be worry free.
 
Last edited:

OSS

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Rust film (as shown) coating the inner water jacket of the head and block won’t degrade engine cooling.
When it gets really chunky, it sloughs off while the engine is running and can clog to top of the radiator if chunks are circulating.
But the picture you showed doesn’t look bad.
 
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No worries, looks fine.
 
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That’s nasty @HemiAlex

Good advice above, flush a couple times real well and put a good mix in.

On rust….my last cooling system refresh also included changing coolant types so I did 3-4 complete flushes with straight distilled water, ran it for about a day with just water each time. After leaving the water in longer than anticipated a couple times I was amazed at how quickly the water got rusty.
With new fresh coolant mix in the rust stopped immediately. Rust inhibitors in that stuff works!
 
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Just flush it, run it, repeat. My Toyota pickup looked like that, it was fine other than it staining the water brown.
 

TStro

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After the flush should I use red or green coolant? The dealership used red, but I don't know what was in there previously.
 
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After the flush should I use red or green coolant? The dealership used red, but I don't know what was in there previously.
Everyone swears on Toyota Red koolaid because it's the cultish kinda thing we do here, we drink the koolaid......me too, I ran Red for years in my 62. And it is good stuff.

I made the switch back to good old name brand Lime green coolant...hence my reference in post #6 to flushing my system 3-4 times very thoroughly. My reasoning, if it's something like antifreeze/coolant that could be needed anytime anywhere out on the road, middle of nowhere, etc I wanted something I could find at Walmart, or Mom n Pops auto parts if needed, without worry of cross mixing coolant types.
You ain't gonna find Toyota Red in those places.
Also pretty sure in the mid-late 80's these rigs weren't being sold with the red stuff.

You can't go wrong with either if properly maintained. $0.02.
 

TStro

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Everyone swears on Toyota Red koolaid because it's the cultish kinda thing we do here, we drink the koolaid......me too, I ran Red for years in my 62. And it is good stuff.

I made the switch back to good old name brand Lime green coolant...hence my reference in post #6 to flushing my system 3-4 times very thoroughly. My reasoning, if it's something like antifreeze/coolant that could be needed anytime anywhere out on the road, middle of nowhere, etc I wanted something I could find at Walmart, or Mom n Pops auto parts if needed, without worry of cross mixing coolant types.
You ain't gonna find Toyota Red in those places.
Also pretty sure in the mid-late 80's these rigs weren't being sold with the red stuff.

You can't go wrong with either if properly maintained. $0.02.
Thanks for the realistic approach thought process. It makes sense.
 
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I decided to replace my thermostat this weekend on my 89 FJ62 with 223k miles. I've got detailed service records going back to 1992. I've been running a high idle, about 950, so I decided to swap the thermostat since I have no record of it being done. I purchased all new sensors and the lower housing. I also needed to replace my AC idler pulley. It still squeals like a banshee after replacing the compressor, bearing, and new belts. I removed the fan shroud, fan, and clutch as well, taking the time to split the shroud correctly. The thermostat housing came out without too much of an issue. All bolts were intact. My big concern is the inside of the head. See the picture. Should I be concerned with all the rust? I had the coolant flushed and replaced at a local dealer less than 2000 miles ago with Toyota Red coolant. My temp gauge never showed hot, in fact, I thought the gauge always showed low temps. Should I re-flush? Is there a special sauce to flush it with other than distilled water? I searched the threads but couldn't find anything. Thanks in advance!
View attachment 2991735View attachment 2991736
As a side note - When I recently replaced water pump, thermostat, and thermostat housing, I also replaced/rewired all the sensors on the housing. Before that time my gauge always showed lower than expected temp but with new temp sending unit it shows higher than expected...
 

ToyotaMatt

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I decided to replace my thermostat this weekend on my 89 FJ62 with 223k miles. I've got detailed service records going back to 1992. I've been running a high idle, about 950, so I decided to swap the thermostat since I have no record of it being done. I purchased all new sensors and the lower housing. I also needed to replace my AC idler pulley. It still squeals like a banshee after replacing the compressor, bearing, and new belts. I removed the fan shroud, fan, and clutch as well, taking the time to split the shroud correctly. The thermostat housing came out without too much of an issue. All bolts were intact. My big concern is the inside of the head. See the picture. Should I be concerned with all the rust? I had the coolant flushed and replaced at a local dealer less than 2000 miles ago with Toyota Red coolant. My temp gauge never showed hot, in fact, I thought the gauge always showed low temps. Should I re-flush? Is there a special sauce to flush it with other than distilled water? I searched the threads but couldn't find anything. Thanks in advance!
View attachment 2991735View attachment 2991736


if need any assistance please feel free to PM me , i specialize on the unique 3FE Thermostat housings topic from several point's of view ,


i have a lions share of problem solving solutions as well :)

also , a few MODERN updated materials / parts ALL OEM with the purist based mind set approach always , like studs and smooth flange nuts verses the four typical long 12mm hex bolts ......


see my T-TEN educational tutorial tech video below , its a 2 bolt 2F housing , the tech and concept are 100% same in kind .........fyi




thanks
matt


3FE PLUG and PLAY REPAIR KIT Cold Start Injector Thermal Time for EFI Timer Switch SENSOR Sender for Land Cruiser FJ62 FJ80 Pick-up 4Runner Fits 88 -90 FJ62 USA & Canada Spec. sensor sender 91-92 FJ80 89462-20040 - VintageTEqParts.com - https://vintageteqparts.com/collections/electrical/products/copy-of-3fe-plug-and-play-repair-kit-oem-toyota-valve-bimetal-vacuum-switching-no-2-for-e-f-i-25820-fits-88-90-fj62-usa-canada-spec-sensor-sender-3fe-vacuum-hose-too-fj80-also



















































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