: 1999 STS leaking coolant

07-28-14, 03:32 PM
Hello everyone! I am brand new to this forum and I obviously need help! '99 Seville TS is leaking(losing)water despite new radiator installed, and the mechanic says that it's the head gesket.The car does not over heat and does not blow white smoke at the exhaust. Can anybody help?

07-28-14, 03:47 PM
Get to a large parts store and rent a cooling system pressure test kit AND a cylinder block exhaust gas test kit.

With the engine cold - and the proper SLS surge tank pressure tester adapter - pump the system up to 16 psi and start looking for leaks - strong flashlight.

No leaks ??? Take the car for a spirited drive, come home and let it cool for a half hour. Use the block gas test kit according to directions - you sniff the airspace over the coolant in the surge tank (proper level is 1/2 full, cold) for the presence of exhaust gas = bad head gasket(s).

Read the sticky posts at the top of this forum page - The ones on fan operation, cooling systems, and gauge operation. Basic knowledge that you need.

Not to cause anxiety, but you might want to study the non-scientific poll just above - the headgasket failure poll.

07-28-14, 08:55 PM
Where exactly are you seeing the leak (as best as you can describe it)?

Find a new mechanic. This one has no credibility.