Have you replaced the heating core yet?
The thermostat on a 1991 Buick Skylark is located near the engine. To find the thermostat, follow the top radiator hose directly to the thermostat.
From a small pipe connected from the top of the engine to a radiator hose.
You can find the 1991 Buick Skylark radiator drain plug on the bottom of the radiator. The radiator drain plug will be in the center of the radiator bottom.
follow the upper radiator hose from the radiator to the motor. it will be inside the housing the hose attaches to. ps...not easy to replace
Hey Mike==Follow the upper radiator hose from the radiator to the engine and at the engine there is a housing that contains the thermostat. When replacing it make sure the spring goes toward the engine. GoodluckJoe
If you follow the hose from the drivers side of the radiator, it will lead you up to the end of the thermostat housing. It is under the air cleaner. There is a lot of stuff you need to remove to get to it. Good luck.
It uses the cap on the coolant recovery tank as its "radiator cap".
If it has a coolant tank, that's the "cap".
There should be a housing that a radiator hose is hooked to. The housing bolts up to the engine block just under the throttle body(the thing the air intake hose hooks up to). The thermostat is behind the housing. This is true for a 3100 buick engine. But in all cases that I know of it will be close to the end of a radiator hose. Hope this helps.
The thermostat on 4 cylinder, 2.3L Buick Skylark is on the bottom of the water pump. Remove the metal water line connected to the bottom of the water pump to find it. Remember the new O-ring with the new thermostat.
Follow the top radiator hose down to the water outlet. The stat is in there. Let me know if this helps you. Mark
If there is no petcock on the bottom of the radiator then you must remove the lower radiator hose to drain it.