[Gor]

Hi!

I have a '97 Mercury Sable w/Duratec V6. (104k miles)

On my way home from work last night I noticed my A/C wasn't cold, I looked at the temperature and it was almost to the redline.
Switching on the heater vents blew out cool air instead of hot.
The coolant was boiling off the header tank.

On getting it home, refilling the header tank and running it again, the same thing happened.

- Start engine.
- Heats up.
- Fans kick in.
- Coolant system appears pressurized.
- Temperature keeps rising.

Now, under the car where the thermostat housing is, the coolant pipe is hot on the engine/pump side of things, and on the radiator side, it's relatively cool.

Do you think the thermostat is stuck closed?

Also, the thermostat housing seems to have a smooth "dent" in it. Is this shape supposed to be there, or has a rock caused this?

Any help gratefully appreciated!!

Thanks!
Gordon.

 

[Gor]

OK,

I went ahead and replaced the thermostat - it's still the same.

Temp still rises as far as you'll let it without turning the engine off, and the heater still blows cool air ...

Any suggestions? Please?!

 

[shoz123]

If the heater is blowing cool air when the motor is hot it is either because of air in the system or a bad water pump.

 

[silvapain]

bingo.

The heater core is directly tied into the engine coolant system after the block. If it's not getting hot, then there is no water flow through it.

 

[Gor]

I'd heard that it's "rare for a water pump to go and not leak".

There's been no leaks from anywhere....

I guess anything's possible.

Anyone know how much a water pump is?

Thanks Guys!

 

[Gor]

I gave the cooling system a good flush, and now the temperature fluctuates a bit, but never goes real high (redline).

-BUT- Now the oil light flickers when the engine is hot and idling. If I rev it, the light goes out, but comes back on again when it reaches idling speed.

There aren't and weird noises or anything coming from the engine.....

Any ideas guys?

THANKS!

 

[Gor]

UPDATE:
It doesn't do the oil light thing anymore, but I'm still back to square one.

I've changed the thermostat and flushed the cooling system.

Heater not blowing hot.
Car overheating.

Any ideas?

 

[green]

You can try removing Tstat and see if car still overheats with it removed. The water pump inpeller could have came lose from the shaft so the shaft is turning but the inpellers not or, blown head gasket

 

[shoz123]

It's easy to see if the water pump is working. Take off the upper radiator hose, wait till the t-stat opens and when it does hot coolant will come out.

I suggest you do this as it appears you are burning you motor up as evidenced by the oil light.

 

[Gor]

Thanks green and SHOZ123...

I'll take off the upper hose and see.

I'm assuming that if hot coolant doesn't come out, then I either had a T-stat problem OR a water pump problem.

If I take out the thermostat and try the "upper radiator hose" thing and it STILL doesn't work, then it's a water pump... correct?

I'd hate to have to pay $1000 to get the thing fixed, you know?

 

[shoz123]

Well you could just disconnect a heater hose. If the water pump is not pumping the engine will overheat in a couple of minutes. And no water will come out of the heater hose.

 

[Gor]

Yeah I took the thermostat out and disconnected the upper radiator hose and nothing -----

I guess it is the water pump.

Is there a way to change this without having to take out the engine block? It looks like it could be a hell of a job to do. The water pump is right there, but you can't get to the bolts which hold it ...

 

[snyper1982]

sure you can, but youll need some crows foot wrenches. i had a shop change out my water pump for under 200. its not THAT expensive. and the only reason THEY changed it, is because they called my dad instead of me, or else i would have changed it myself.

 

[stugee]

Easier way to check Water Pump / DOHC V6

Here's a quicker and easier way to check your DOHC V6 water pump (assuming it does not leak, make noise, or if the pulley doesn't wiggle when pushed on).

With the engine off and cooled down:

Pull off the upper hose where it connects to the water pump. (You'll lose a bit of antifreeze unless you drain the coolant first; otherwise just pinch the end of the hose when you pull it off and point it upwards to avoid losing more antifreeze.)

Stick your finger into the water pump outlet and feel for the impeller blades. If you feel a loose piece (as I did on my 97), then the impeller has broken apart and the pump needs to be replaced.

Symptoms of the bad pump impeller were similar to a head gasket: Overheating after about 8 minutes of running, but no leaks or noises from the pump. If the engine ran more than 8 minutes, the pressurized reservoir started to bubble and boil and antifreeze would leak out of the cap.