I have a coolant leak at the thermostat housing. I was going to replace the seal and housing but the rear bolts are seized. What are the implications if I crack off those rear bolts. I assume I would have to pull the manifold if that were to happen. How much work is involved in pulling the manifold?

 

Seized . . . or just very difficult to get to?

All that have replaced the plastic housing have struggled with those bolts. I ground down a 1/4" socket, some have bent a wrench or used a crows foot wrench. Did you remove as much of the old housing with a pair of pliers as possible? That will help a lot.

I assume that you are going to replace it with the aluminum version. Consider painting it black as the bright aluminum looks out of place on an otherwise black engine.

Removing the manifold is not difficult, just involves pulling a lot of stuff.

 

Ya they are seized. Confirmed by the dealer as well. That is why I am debating getting them to do it especially if the bolts break. I don't want to have to remove the manifold myself so I was wondering how much of the top needs to be removed if that were the case.

 

I suggest obtaining some Kroil penetrant from Kano Labs. I have never had a seized bolt that this would not break loose, and I restore old motorcycles. It is the best product of its kind out there....by far. Ity sure beats going to machine shops to fix broken parts.

 

You do not have to remove the manifold completely.
Remove the bolts along side of the injectors. It should then tilt back on two fasteners at the throttle body. You can put a socket on the thermostat bolts and hopefully remove them.

 

I have never tried this stuff myself ...
http://mgaguru.com/mgtech/universal/ut102p.htm
but people seem to love it.

Worth a try if all else fails.

 

Soak the area with penetrating oil (as suggested) and then

Run the motor and get the car as hot as you can, and then try again??

 

The top of the rear bolt heads are rounded from not being able to get to them properly. They became rounded from the corrosion due to the leaking coolant. A crowfoot wrench did not work either. Looks like my only option is the partially remove the manifold and tilt it back.

 

If you can cut a slot in the top of the bolt with a dremal tool or hacksaw blade, broken bolts/frozen can be removed with a screwdriver. Also gently/sharply tap on bolt head with hammer and drift, this can loosen the bolt.
Good luck
BobF

 

Bingo... FTW

 

I was able to start removing the two rear bolts. Bending a combination wrench did the trick. Once I cracked the bolts I started removing them with my fingers. I thought I had victory in hand. Now the rear bolts come so far out that the flat part of the bolt butts up against the manifold. Any ideas?

 

I had that problem also. I think I just put a little presure on the blots in the forward direction by tilting the tower and they came free. It has been a few months since I did this, but I remember the issue, thought I had a major problem, but they just kinda came free with a bit of "help"

 

This is great - I have everything in the garage anyway.

 

Some people replace them with hex head bolts.

 

That worked! Thanks. Talk about a PITA job. Looks good with the tower finally removed. I can see where the seal was leaking. What a relief to get this done without removing the manifold. I will be replacing the rear bolts with the shorter bolts from the thermostat seal.

 

Congratulations! You are awarded a thermostat housing merit badge!

That was more difficult than tensioners.