Thermostat

My 2000 3.4 Impala temp never seems to get very warm only about 1/8 the way up on the guage maybe get has high as 1/4 if I drive around town in stop and go traffic for about a hour . It runs great but i'm just worred about the low operating temp it used to avg about 1/2 way or just above before the intake gasket and water pump got replaced. This has been going on since early dec we it was 40-50 deg outside it just takes abit longer to warmup now that is -0 deg now.
I just took out the coolant level sensor and cleaned it because the low level warning would come on for about 2-5 min after starting car for about a week before I cleaned it. It wasn't that dirty so it and works again or maybe it just stoped working all together either way the warning isn't on any more.

Now I think the temp problem is in the thermostat does anybody know if there is a easy way to change it looks like a pain to get to but have not realy look that close at it or is there any how to or guides out there for this job I have changed thermostats before but never with all this crap in the way. Was also going to change the temp sensor because it is right by there when I do the thermostat change.

I think this will solve my problem but not for sure. If anybody has any other suggestion that would be great. The only other things that I can think of that might be part of the problem is that the temp gauge red lined and no heat blowing from heater I think it did this because of a high water % in rad and it froze but pulled over right away and turned car off. It did this right before I got the intake gaskets replaced.
the heater blower makes nosies every once in awile but warm air does come out on all setting just figure the blower motor is going out.

was told by somebody at work that it could just be the temp gauge

The temp issue is probably natural due to the cold outside temps. My car is running cooler than normal right now (2 to 3 marks on the gauge), as temps here in Michigan have been in the low single digits and below zero F for over 2 weeks now.

The temp issue is probably natural due to the cold outside temps. My car is running cooler than normal right now (2 to 3 marks on the gauge), as temps here in Michigan have been in the low single digits and below zero F for over 2 weeks now.

I'm in indianapolis and its pretty cold here too and my gauge barely gets past were the gauge even starts right now. I was told that 1/2 way is the normal operating temp for my car and thats what it was before the intake gasket and water pump got replaced. The low operating temp has been going on before if was cold it has just gotten worst because of the cold. My car is garage kept, only parked in the cold at work for 9 hours at night.

ok, then it probably is a bad t-stat. It should have been changed when the intake was done, as it is a bear to get to with the intake installed (and takes 30 seconds to change with the intake off). It's mounted horizontally under the throttle body, and the back bolt is virtually if not impossible to reach with the t/body on the car.