1998 Toyota Sienna Thermostat Housing Stud Broken

Hi kc0dxh,

Thank you for the donation.

Good thing you still have a long portion left of the stud but bad news is it is in a rather unaccesible location.
Check with your local parts outlets that has a loan program for a stud removing tools. With it clamped onto the stud, the stud can be removed and replacement made.

You can try removing the upper hose for accessibility and try removing the stud with the aid of a grip plier. Filing the stud on one side to make it slightly flat for better grip would help. Spraying some rust remover and letting it soak prior to removing would help.

Do NOT allow plier to slip and damage the stud as it would cause difficulty in removing. If the stud is damaged too bad, you would have to drill it out and retap the threads.

Worse case scenario is to remove the complete housing and clamp the broken stud on a bench vise to remove.

While working on it, take care not to damage the housing to prevent leaking.

To install new stud, use 2 nuts to lock onto each other on the stud and tighten, need not be too tight, 8 ft.lb would do.

So, are you saying that stud will just unscrew, provided I can get a good grip on it?

Yes, it is threaded on the other end as well and is just screwed on. However during installation, it might get stuck a little tight.

That was the piece of information I needed. Thanks so much! It unscrewed surprisingly easily with a vice-grip. No muss, no fuss.

Now I just need to locate a replacement, but I don't think that will be a problem. Two parts stores nearby say they should have them.

Cheers. Should you have problem getting them, which I doubt so as it should be readily available, you can try the local scrap yard. Should be plenty there and it is a generic item which you only need to get the correct length and metric size, does not matter what make.