bolts are really corroded,

the two that hold the thermostat housing to the block,

anyone replace these, and where did you get them?

I saw one thread that listed a size of (5/16x18 and the head is 1/2)

this is for a 300 4.9 six cylinder.

 

Just did this. Po used locktite and with corrosion they broke. Heat the surrounding area first, then slowly try and remove them. Mine were 5/16 coarse thread.

 

When you put it back together use anti seize on the bolts and next time they will come right out.
Dave ----

 

the bolt thread is 5-16x18, 1 inch long just about, and some flat washers,

is what I got...... grade 8......

I was worried that the bolts being so corroded that when I put them back in, they might snap off in the block,

good idea on the anti-seize, going to do that today in the rain.

oh crap.

got a new 195 degree thermostat just because, knowing my luck, I would just change the gasket, and the dang thermostat would quit working a week later.

haha.

 

My bolts were stripped so I used a hammer and broke off the housing ($10 to replace) and came with new bolts. Also autozone sells a bolt package for that years truck that has a good selection of replacement engine bolts

 

Replace them with 5/16 carb studs, use anti-seize on the nuts and never worry about breaking them off again.

 

Great idea to replace with studs

 

I forgot to check and see if O'Rileys sold thermostat bolts, I'd would have rather just bought them in a kit, the bolts in the block were really bad. probably would have broke off in the block, once re-tightened.

forgot to mention, just got this project wrapped up tonight.

the first gasket I got was from Advance auto $2, felpro I think,

I used some of the grey 'glycol resistant' gasket maker, shouldn't have used that type of sealant, will never again, not enough in the tube to make a proper seal. and I gave it plenty of time to set up, and the thermostat housing leaked afterwards. worse than it did before I changed the gasket.



so I got the trusty heat resistant red sealant, and got a cheap thermostat gasket from O'Rielys for $1, and resealed it, with a lot! especially near the bottom of the thermostat housing, and let it set up,

good news is now it doesn't leak at all now.

 

This isn't rocket science. The bolts are 5/16-18 about an inch long. Soak them with your favorite penetrating fluid. Try to work the bolt back and forth to get it out. If it doesn't want come loose heat is your friend just don't get carried away. And if needed cutting the heads off or breaking the housing are options. How ever you get the bolts out make sure and chase the bolt hole threads flush and blow dry. For bolts any hardware store grade 5 or better bolt is fine use anti-seize on the threads and bolt body. Torque to spec

 

Can you elaborate? I'm having trouble getting my thermostat housing to seal, if it worked for you it should work for me!

 

I changed my water pump, and used Red RTV (Permatex High Temp RTV Silicone)

US Part Number: 81160
Canada Part Number: 59403

I saw a small grey tube of 'glycol resistant' in the parts store, never have used it before and wont again, not enough in the small tube to make a good seal.

I've used red rtv on different vehicles in the past, and never have had to reseal.

the only time it doesnt work, is on something like a axle seal, you have to get the black rtv (grease resistant) silicone for that.

I put a good amount around the block, esp. around the bottom of the block, being careful not to get any in the block cut out for the thermostat, getting some in the bolt holes doesnt hurt.

then I put a good amount around the thermostat housing,

the I put a good amount around both sides of the gasket,

then placed the thermostat into place, and then bolted on the thermostat housing.

you dont have to goop the silicone on, but you want enough to when you tighten the thermostat housing on the block, it pushes the silicone around the thermostat housing and gasket,

then give it plenty of time to dry, 24 hours at least,

I dont have a garage, the second time I sealed the thermostat, like I mentioned earlier, it wasnt raining, so I left the hood up on my truck overnight until the next night to let the cold air dry it. haha.