Am losing coolant on my 1995 Park Avenue with the 3800 Series II engine. No visible leaks on reservoir, hose, radiator cap. Yesterday, the local Buick dealer/garage did a pressure test on the car. Stated there was no pressure drop (held the pressure). Looking for help or any suggestions..

Try changing your upper and lower radiator hoses. You might also want to check the bypass hose, which is a small hose underneath the alternator.

The 3800 series 2 had a problem with coolant leaking past the throttle body gasket. A new seal was introduced for this concern.

If the coolant is leaking at the throttle body the coolant leaks on the exhaust manifold and gets burned off and you will see no coolant leak. Look under the throttle body below the nut/studs and see if you can see a crust build up on the area between the throttle body and upper intake.

Yesterday, backed the car out of the garage into sunlight. Took your suggestions and looked at the hoses again. Looked under the car on the driveway and there was a small puddle. Turned out it was under the water pump. Ran the engine and there was drip about every 45 seconds or so. Coolant on the front side of the water pump. Took back to Buick dealer/service. Don't know why this didn't show during the pressure test. Anyway, got it fixed. Fingers are crossed that this was the only problem. Thanks for the help.

A leaky bypass hose would run down the water pump, I believe. Glad we could help!