Coolant leak

My 2003 Buick leasable has a liquid on top on engine I think is antifreeze and I recently got a code on the liquid coolant sending unit. I have to add coolant, but car has never been real low of fluid or hot. What do you think is this a common problem with this car? Where is the coolant sending unit?

The most common cause for coolant on top of the engine on your vehicle are failed intake manifold gaskets. Have you checked the condition of the engine oil?

Tester

Have oil changed at local garage and never noticed and sign of water in oil, no milkey look. What do you think about coolant sealer?

i have a 2004 Buick lesabre that smelled for quite a while of coolant smell. i finally noticed that it was leaking slightly from the intake manifold gasket. a usual problem for this car. some blamed dex cool-- some said no. it really did not leak much---- but the smell ( not inside) but when you got out of the car was brutal. i had it fixed by my mechanic. so far so good. i was worried it would some how ruin my engine if the leak got worse. i think it cost between 300 to 400 to get it fixed. i had a couple of new tires put on so i don’t remember the exact cost just for the gasket fix. but it’s close. i love my car so it was worth it. good luck

Don’t know where your thermostat is located at but if its mounted on top of the engine you might check to see if the thermostat houseing or hose is leaking.