Definite coolant not washer in both the driver and passenger footwell, no coolant left in the coolant level bottle in the engine, slight engine misfire and runs slightly 'fluffy'. Although engine still pulls there is a distinct loss of power as if compression was leaking. some erratic electrics

Most likely problem is a leaking heater core. This is what usually causes water leaking into the passenger compartment. Quick fix on many vehicles is to get a hose adapter the same internal diameter as the heater hoses, remove the heater hoses from the firewall connection to the heater core, and install the adapter, making a bypass loop. This will allow operation of the vehicle without coolant loss until you can replace the heater core. Of course you will have no heat in the passenger compartment during this time.

A 91 should have regular green coolant. Make sure to read the label on the bottle. Sometimes it is premixed and some times you need to mix it yourself. If you have to mix it your self you will use 1/2 coolant and 1/2 water.

You can add it directly into the radiator through the radiator cap. Make sure the engine is cold before you remove the radiator cap!. Once the radiator is full you can top off the overflow container. It should be on the passenger side of the car near the battery. It will be the white bottle with a black hose going into it.

Do not mistake this with the washer bottle. The washer bottle will have the blue cap.

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When you open your hood, you will be finding it on the left top area. An reservoir will provided to refill and maintain the level

Does it have to do with the AC. I had a similar problem with my vitara and they said a washer was prob loose in the ac system which would cause the water to leak to the footwell. Mine was only the passenger side.

replace washer bottle while its out silicone the inner fender where the water is coming thru

HEY Cassey;

here's your answer....

first when you po the hood you will find two white plastic bottles. One is going to have a bluish fluid in it. That's the window wash fluid. The other is more yellow to green looking and has markings on its side saying hot and col levels. top up that bottle to the level indicator depending on if the engine is hot or cold. Hot=has been running 10-20 minutes.bon chance

That is the area the air conditioner vent drains. There aren't a lot of fluids possible - coolant, power steering fluid and transmission fluid are the only ones that would be in that position unless your windshield washer fluid leaks from the tubing. Brake fluid would be closer to the wheels. If the air conditioner runs at all it removes moisture from the passenger compartment and drains near the passenger side firewall. All the other fluids would hae a definite smell.

which fluids are you trying to check? there are about 6 that you can check under the hood depending on if its an automatic or stick shift. The oil is the one with a bright yellow ring on the end. Check this with the engine off. Power steering will be in a bottle looking thing on the passenger side with dark fluid in it. the bottle is see through and has lines on the outside to tell you its full. same with the coolant but the fluid in that will either be green or red. brake fluid is on the driver side towards the windshield and is in a clear container also. The automatic transmission will be a red handle that is on the passenger side towards the rear of the engine. Check this with the truck running in park. washer fluid is blue and will have a picture on top of it that looks like a windshield. make sure when you check everything that the truck is on level ground

your buick century has a low coolant level sensor located in the passenger side of the radiator , sometiomes the sensor get covered with coolant sludge and will show that the cooling system is not filled , sometime the radiator is just still low on coolant . check the radiator when the engine is cold ( IF HOT WAIT !!! 30 mins ) and make sure the level is above the sensor.

are you sure it's the washer bottle sounds like the heater core is gone if window is fogging up it's the heater core