Thermostat Change - can this be done stand-alone?

[Phantasm]

Hello,
1991 SE 2.2 engine.
I read in the forum somewhere that the Thermostat can be changed out without pulling the timing belt or anything else apart aside from the timing belt cover. Can anyone confirm this?
It looks like there is enough space to get it out, but need to be sure.

Part number: I've seen various part numbers but this seemed the most consistent: QTH104K I know this is the kit, but will I need any other gaskets once I open up the housing to put it back together?

Background: My car takes forever to get marginally warm and while underway doesn't warm the interior in the least. I can drive 10 miles or more and never reach 80. If I let it idle after driving 10 miles or do some hard acceleration starting/ stopping I can get it to break 80 but don't want to do that to a 'cold engine' to heat it up. Once I do get the car warmed up, the car blows nice and toasty warm air. Thus, I think my Thermostat is stuck open.
I flushed and changed the coolant a few months ago without issues.

[CHRISYD]

Yes, I would say stat stuck open, or missing! I think if you can remove the bolts holding the top of the housing on, then you should be able to slide the top cover sideways.

[fueltheburn]

QTH104K will come with a gasket.
The thermostat housing can be removed with cambelt in place and no need to remove anything else. It may take a bit of time to get the bolts out as you need the open end of the spanner and will only get a few degrees each turn.
A wee bit annoying but should be off fairly quick.

[MrCoolA]

I changed my bolts to Alan key type bolts makes life a lot easier to remove oh and yes u can remove without removing anything else. Good time to convert to Alan key.

[Phantasm]

I received the part today and had it installed well within 2 hours just plodding away at it. Short story, problem fixed.
The job is pretty simple...
Remove the hood for easy access.
Put a wide drip pan under the car.
Remove the cam cover, 3 twist locks or in my case 1 and cut some zip ties.
Pinch off the coolant reservoir tube to the elbow so it doesn't drain out. I used a vice grip. quick and easy.
Remove the two bolts holding the elbow on- 13mm Socket. Once broken loose I used a 1/4" wrench and socket with an extension as they are smaller in diameter and I was able to back the bolt off under the timing belt with ease. I did slide the belt an 1/8" or so off the cam sprocket and then gave the belt a little twist to ease the socket in there.
Separate the elbow from the engine; Fluid will spill at this point.
Clean up the mating surfaces. My old gasket was caked on pretty well.
The QTH104K did come with a gasket, but it was a universal multipurpose design able to be fitted to numerous applications. I found the correct hole alignment and traced it out along the flange edge, then cut it to shape. Being multipurpose it had hole pop outs all over it and cutting through them caused a few small moon shaped gaps in the gasket edges. I didn't care for the missing sections, so I added a thin coating of High temp silicone to both sides of the gasket to ensure a good watertight seal.
Bolt the gasket in with the new t-stat seated in place.
Put the cam cover back on
Reattach the hood
Let it rest a while, and give it a spin.
The car warmed up to 80 in about 3 minutes (it's raining and about 4-5*C outside) and when it reached 90 the fans kicked on which was good to see! In normal driving it stayed near 80, at rest it rose to 90. I did note my oil pressure is running lower now that the engine is warming up faster. from 4-5 to 2-3 bar. I added 1/2 quart as I know the car loses oil at the top cam's carrier seal and it had been a while since I replenished.

I later tested the old T-stat, appears to be working, so I'm not sure what was stuck open or not working on it, perhaps some debris got caught in there and came clean without my noticing. Hopefully it's not circling around in my cooling system waiting to get caught up again.