Ok. My buick century has 78,700 original miles and ive driven it the past 5 years and put the last 45,000 miles on it. about a year ago the reserve tank for the coolant was leaking so i tried to replace it with a crap tank. I would have honestly been better off with the leaky reserve tank. EVer sicne then I've beenputting antifreeze in when needed. Lately I went to a junkyard and found the right coolant tank and a good clamp for the hose and replaced it. I'm now trying to sell the car but it keep overheating. The coolant is good, its a light clearish green, but the car still overheats after 20 minutes. This car has been oevrheating when the coolan gets low for about 9 months now, and i kept adding coolant in, it would stop, leak a little more, overheat a little, so i would ad some more. I was it was definately the water pump, then i was told its the thermostat. I recently bought a new thermostat for it cause its the cheaper part. I was also curious on an 89 buick century the thermostat was. A guy who claims to know where they are said theyre near the back of the fan on the radiator, then I talked to someone else who said it was on the engine/radiator hose. I dont know who to believe.

Since I've replaced the tank, it doesnt leak anymore,. but still overheats, before, it would only overheat when the coolant was low, but it still is overheating.

The other day I wanted to see how long it would take to overheat if i sat in the car witht he air on. I sat in the car witht he air on for 15 minutes, nothing. I drove it 3 miles, came back, nothing, so i sat there for another 3-4 minutes or so and then it overheated. so total time was about 21-22 minutes till it overheated. Mind you this is at 4 o clock in the afternoon when it was 90 degrees out.

1989 Buick century Custom 2 door 3.3L V6 2 door

Any and all help is appreciated

Your thermostat can be found if you look at the housing that the top radiator hose connects to at the intake manifold ( this is the thermostat housing and you remove this to replace thermostat )
the thermostat housing has two bolts to hold it in place .
Does your coolant fan ( radiator fan ) come on ? You may have to have the coolant sys. pressure tested for leaks .
Good Luck .
John L.

im pretty sure it doesnt leak, no signs of it.although im not sure if it could be still leaking without anything showing on the hoses or the ground. thanks for the info about the thermostat. The fan used to come on, im not sure if it comes on when the engine gets hot. I was told it comes on when it gets hot. I always thought it was on all the time no matter what.

Also, another question. I take it that the thermostat sits inside coolant fluid. Should I drain the radiator first and then replace the thermostat? or am i way off base?

Also, another question. I take it that the thermostat sits inside coolant fluid. Should I drain the radiator first and then replace the thermostat? or am i way off base?
I wouldn't drain it,you'll find a small amount of coolant but not much,but i would suggest you do it with the motor cold.and watch the way you put it back in,as it's easy if you're not careful to put them in upside down.
good luck and let us know how it works.

To see if your coolant fan is working turn on your A/C sys. ( your A/C sys. must working ) and after it has been running for a short time the coolant fan should turn on.. if not that may be your problem .
HTH
John L.

I ran the car for about 10 minutes with the ac on, the coolant fan did not come on in that time frame. I'm going to see if thats the problem, or see how i can fix it