In my experience with a 3.1 in my Lumina it is on top on the drivers side. Trace the hose from the radiator and you should find the housing. Be sure to refill and bleed both bleeder valves in the system. This is critical in the vehicle not overheating. email me if you have any questions.
I have a 98 Malibu and just changed the thermostat yesterday, it is located on the drivers side of the motor, just under the throttle body. IME it makes your life ALOT easier to take off the throttle body (two little bolts hold a bracket that holds the throttle cables, and the other bolts on the body itself) the bottom right corner bolt will have a little bracket that is used for holding up that hose i believe, take pliers and bend it out of the way, because it is useless and is just in the way, bend that out and follow your hose to your thermostat, it also might prove helpful to remove the heat shield that goes over the exaust pipes, however I did get it out without taking that off.
P.S. If you have had any other problems with this car, let me know, I would like to exchange knowladge about cooling and other problems and possible solutions, I can be reached at litsfosbass@hotmail.com, thanks!
Try in housing at the engine end of the upper radiator hose
Where is the coil pack located on a 1998 Chevy Malibu with 2.4 engine
It is located within the water outlet at the bottom of the top radiator hose. I hope this helps you. Mark
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follow top raditaor hose to engine. Should be right there.
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Infront of the drivers seat.
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