f*&@*#ing thermostat clearance (AKA tips on thermostat removal for carb'd 3g's)

[rigel]

so i have this poorly running 87 carb'd a20a1 i got at auction, and i decided it probably needs a head gasket.

today i was tearing it down, and ran into a problem removing the thermostat housing.

first, the rear nut was just a big pain in the ass to get to and turn. first i thought "more leverage" and got some long-handle wrenches from HF, but those didnt work.

what worked for me was the "s" type box wrenches. (someone else mentioned that the stubby wrenches worked for them too. i considered crow-foot but wasnt able to even get the open ended wrench on the nut reliably so i went with the "s" wrenches.

but then once the nut was removed, i couldnt get the housing off, because the clearance between the end of the rear bolt and one of the high pressure solid pipes (is that the EGR? it goes back into the intake manifold) was too small to pass the housing through. i couldnt get those big ass nuts to move at all either, the shop manual says theyre supposed to be torqued to 50 lb feet or something ridiculous. plus rust and heat cycling. my attempt with a long handle wrench felt like it would wind up rounding it off so i stopped as soon as i felt that.

so, since i have to remove the cylinder head anyway, my solution was to separate the head from the exhaust manifold, including removing the EM dbolts (i had to fix two nuts together to pull out about half of the double-threaded manifold bolts) and then used a prybar to shift the exhaust manifold just enough out of the way to give me clearance to pull out the thermostat housing. but, success!

also, important, leave the radiator drain stopcock open and keep something under it. when i cracked the second thermostat housing nut, a good 3 quarts or so drained out of it. i was lucky i had forgotten to close it after draining the coolant, because i heard something draining out and was able to move a pan under it. if i hadnt been aware of that, i would have had a real mess on my hands.

[Dr_Snooz]

Sounds like you had fun. LOL. On my injected model, the housing bolts had taken on enough coolant, that they were hopelessly seized. I had to replace the entire neck coming off the head and that project was much like you described above. Fortunately, I didn't have to pull the manifold.