2002 Buick PA coolant issue

[adw59]

I purchased this vehicle this week.69k miles..driving 25 miles to my home the temp. control beeped...near my home...my son added near 1 gal of anti freeze....that night there seemed to be a small amount of leakage under the radiator (but none since that date 11/24/14 or 2 + days ago ).. the coolant level in the radiator appeared down 1 inch on one check...on the last check after running and then off...the radiator level was up to the top and the reservoir level was at 1 inch. My son thought there might be a fine/mist spraying in the area near the left lower side of the radiator..since that time with the motor running I placed a piece of file folder down near where he thought there was a mist and saw none on the folder... this car was owed my an elderly person and likely was not driven often of late.

[Blue Bowtie]

Pressure testing is the customary method to locate leaks. That can be performed with a dedicated pressure tester or by starting the engine and allowing it to reach operating temperature. Shutting off the engine will maintain pressure for some time while making it safer and easier to inspect the suspicious areas, since the fans and engine would not be running.

What engine is in the Buick? Most likely it's the Buick 231 V-6, which has some typical coolant leak areas. If by some slim chance it's the Chevy V-6, it also has some (different) leak areas.

[adw59]

Thanks for the info... I drove it within the hour ..checked the radiator and tank before and after...before ..the radiator level was somewhat normal....after....near overflowing at the cap area....the tank was near empty on both checks..measuring about 1 " on the side....(we filled the tank to the cold level when we originally noticed the temp indicator alarm). I saw no leakage underneath

[Blue Bowtie]

Just maintain the level in the overflow tank to the correct level and it should eventually stabilize, which may take several drive and cooling cycles since the system was a gallon low.

[Tech II]

I agree with Blue......your coolant level was low.......you topped it off......but if it was low, that means you have an air pocket.....like Blue has suggested, check the level when cold(before first start of the day)......top off radiator and make sure the reservoir is topped off to the cold mark)....use 50/50 solution....proper procedure is to bleed the system of air with a Lisle funnel....

If the leak is very small, after several drive cycles, your levels should stabilize....

However, the usual possibilities for a leak are the radiator/heater core hoses, w/p weep hole, radiator, and heater core, for external leaks.....

Upper plenum gasket, Upper plenum, and lower intake gaskets, are the usual internal leaks.....

I don't know if it is an intake leak, or how bad the leak is.....while you are checking this out, to see how bad the leak is, I would do an immediate oil change, just in case coolant has been getting into the oil over time.....

If you continue to have to top off the coolant, when checking first thing in the morning, and a pressure test, as Blue has suggested shows nothing external, then I think you have an internal upper engine leak......fact you noticed it while driving home, tells me the previous owners knew this too....