Bolts on Bottom Thermostat Housing?

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I have an 87 FJ60. I am redoing my cooling system and discovered an issue. Does anyone know what these are/what they do? I had my engine rebuilt where the shop broke them and instead of fixing them they just plugged them. It appears to be part of the vacuum system but I do not understand why they are attached to the thermostat housing where there is coolant. I have been having overheating issues so could this be contributing to the problem? Any input is greatly appreciated!
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Those are valves that open or close based on the temp of your coolant and they control your EGR and emission systems
 
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That is a bummer. If you’re not running smog equipment it doesn’t matter. If you have to pass emissions you’re SOL unless you replace them. They’re designed to open and close based on engine coolant temps and they control the emissions systems on your truck. As spikestrip says they’re bimetal valves meaning there are two different metals inside them (brass and... aluminum? Steel? I should know I just drilled one out of my tstat housing) and when the engine temp reaches a certain point the metal will expand allowing a spring piston to open and thus changes the direction of the vacuum pull which engages emission control functions. The plastic bits that are broken are the vacuum ports that connect to the rest of the emissions system. You can find replacements online. They ain’t cheap. They are no longer available through Toyota so you’ll have to do some internet searching. If they are important to you I would suggest getting some NOS units as the used ones are brittle (as you can tell) and sometimes don’t work. One of them is pink and the other is purple. The plastic changes color with age.
 
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Unfortunately it is not desmogged and I do have to pass emissions. I found two online from CruiserParts.net, however, they are not exact matching numbers nor have I ever ordered from them. Does anyone know if they are a reliable company? I will keep searching in the meantime! Thank you all for your feedback!
 
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Unfortunately it is not desmogged and I do have to pass emissions. I found two online from CruiserParts.net, however, they are not exact matching numbers nor have I ever ordered from them. Does anyone know if they are a reliable company? I will keep searching in the meantime! Thank you all for your feedback!
They’re hit or miss. Lots of people have been burned by them before. There’s a vendor who was selling NOS ones in the past but I’m not sure who it was... I’ll look around...
 
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Cityracer is awesome! He’s a member here on the forum... forget his handle though... is it racer65?? I dunno. Order those. You won’t find a better deal from a better vendor.

The purple one goes on top and the pink on the bottom. Be careful installing them and don’t over tighten them. I suggest installing the tstat housing gaskets dry with no silicone. Same with the water pump. Check out cruiseroutfitters.com for OEM gaskets and water pump. There have been several of us who’ve bought counterfeit aisin parts on eBay and Amazon recently and it’s a bummer.
 
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here is a good post from the archives:

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OSS

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If you let the engine warm up before driving off, you don’t need them. The vacuum hoses can be connected in a loop as if they were connected to those valves.

Both of the valves just make sure that something doesn’t happen when the engine is cold. EGR system won’t be active (because EGR injected into a cold engine will make it stumble) and Choke Opener will be disabled (since you want the choke to work when the engine is cold).

When those BVSVs warmed up, they opened up and both those systems became active (back when they were functioning).

With the Choke Opener disabled, be sure to NEVER pull out the choke knob after start up. It’ll make the engine run way too rich cuz choke plate is actually working.

You won’t fail a smog test without those valves connected. Just loop the vacuum hoses so they look clean and tidy
 

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