I know this a TRUCK FOURM but I am having problems with my 1996 Mercury Sable. I have replaced the radiator, the tank cap, the thermostat and checked all my lines and it still over heats. The Anti-freeze is moving in the system, it takes around 15-20 mins on idle to over heat and if I put it in gear it heats up faster. I can maybe drive it 15 mins before it over heats. I have checked my oil, oil pan, alternator and fans all are fine. The water pump circulates so I have no clue. Please post me ideas.

 

Check for oil to change color and become foamy. indicate antifreeze in the engine via a cracked head gasket.

One other thing which you did not mention and as simple as it may sound do the cooling fans turn on at all? I believe the sable has electric fans... do they come on at all? If you put the a/c on the fans should also come on.. just a thought...

 

Weren't these vehicles known for cracking heads or blowing head gaskets. Something in my mind says that. Do a pressure test of the cooling system.

Craig

 

For one, you may have more success asking in a Taurus-Sable forum:Taurus Car Club of America : Ford Taurus Forum

Which engine, DOHC V6, or OHV V6? The OHV has iron block and heads, and sometimes casting sand and rust accumulates in the lines, and heater core, blocking things. Flushing would be a good next step.

The thermostat may not be opening. Just because it is new doesn't mean it is not defective.

The two engines available in the 96-05 Sable aren't known for blowing head gaskets. The 3.8l is the bad actor, and the last year for that in a Sable was 1995.

 

Just because coolant is moving within the system doesn't mean that it is moving well enough.

I assume from your wording that the car was overheating to begin with and that's why you have replaced what you have. The only part you haven't replaced yet is the water pump.

I agree with MFJ in that flushing (if your coolant and oil look okay) is the next logical step. It's cheap, it's easy, and it's not a bad idea to do in the first place. Make sure you turn the heater on while you are flushing. If that doesn't get rid of a bunch of rust/ scale and completely alleviate the problem, your water pump most likely is the problem.

I had a water pump go bad on top of a 6700 foot mountain in the summer and I had to drive 40 miles to get to a town. The engine was so hot by the time we got there, we parked it at 10PM and it still wasn't cool by 7 the next morning. When I checked the coolant in the radiator the next morning (with the engine running- a miracle in its own right) I could see the coolant moving. The pump wasn't bad enough to move NO coolant, but it wasn't good enough to keep the thing from getting screaming hot in short order. That's often how they fail.

 

Yeah^^^

Thermostat or water pump. On my truck, I had to let the engine run with cap off to remove a large void of air in the system. It prevented much coolant from moving. Heat would work if I stepped on it but at cruising rpm, it would get really hot while heat blew cool.