Hi, 1992 RM wagon, 78,000 miles, no leak but hear a hissing and losing coolant, slowly.

Asked by Thom Sep 14, 2018 at 11:49 PM about the 1992 Buick Roadmaster Estate Wagon RWD

Question type: Maintenance & Repair

My car doesn't leak anything. In great shape.  I noticed the temp gauge
going up while sitting in a parking lot.  I turned it off before it overheated.
Added cooling and seemed fine for a while. Replaced radiator cap and that
seems to do it.  Now, reservoir level low, added water and after a drive 20
miles, nothing dripping that I can see or that is on the ground, but hear
hissing nosie. what can it be?

9,530

Mike answered 5 years ago

If you hear the hiss after you shut the engine off try this, turn heater off start engine and run for a while then shut it off, hiss gone? If yes thats the normal sound of the a/c system equalizing pressure and is normal you never listened that closely before, If the hiss is still there "burp" air from cooling system I hope this helps you

Mark helpful

F_O_R answered 5 years ago

A small leak might evaporate before it drips onto the ground. I might go ahead and replace the radiator hoses and the radiator if the car is a keeper as the cost is not that high. You could try Alumaseal in the radiator to stop a pin hole leak.

Mark helpful