2000 Ford Taurus Coolant/heater/radiator problems

has your mechanic done a compression test on the cylinders ?

Thank you for responding quickly. No, no tests aside from checking the oil for coolant (head gasket leak suspected?) were done. They said they "just don;t know."

I'm suspecting headgasket as well ... a compression test on all cylinders will rule this out or confirm ? have one done .. this is the only real way of checking the headgasket .. let me know !

Thank you for your help. Would a head gasket problem not manifest itself in other ways, too, such as water/coolant etc in oil, "smokey" exhausts? I will suggest the test if it's not too pricey. Can the car be driven as long as it doesn't get too hot? Thank you.
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your vehicle has already displayed all/most of the signs of a headgasket fault ! the only thing missing is the white smokey exhaust !

When hot, coolant overflowed out of reservoir lid. Next day, coolant had transformed into oily, dirty, thick foam. When hot, coolant overflowed out of reservoir lid. Next day, coolant had transformed into oily, dirty, thick foam.

these are signs of oil getting into coolant, the foam is caused by the compressed gases/air getting into the coolant at the same time as oil !! the overflowing is caused by the gases/air building up pressure in the coolant system and having to find a release somewhere, which is generally the reservoir cap ... or eventually it will burst a pipe/hose or blow a hole in the radiator !

I wouldn't recomend letting this engine get hot while driving could only do more damage (warp head) !

Also, you said in your previous post ....Next drive, heater worked again. Car never got hot again, but fluid is very low when car is off, high when car is on .... is it now running fine again ?? I also think the A/C issue is not related to the coolant .. we can look into this when we pinpoint the coolant issue ...I would have the cylinders compression tested and the coolant system pressure tested at the same time ... let me know

Ok, thank you so much for your help. I will approach a shop for the tests you suggested on Monday and I will repost with the results. I did not realize the symptoms were mostly head gasket related. I thought maybe there was a coolant reaction - the coolant that was in was so dirty that its original color cannot be identified, but I used one that said it could be mixed with anything. Let's see what the tests say. Would a specialty radiator shop be able to do something like this (tests), or is this something a "normal" shop should be able to do? To answer your question about the car running: Yes, the car runs fine per se, stays in "normal temp" zone, the only thing is that it smells like burnt liquid when stopping. I will fill more coolant in today and see if it keeps releasing it again through the reservoir lid. Also, since it first started I have not driven it more than short distances (10 miles max) for fear of breaking down. Thanks.

there should be 2 marks on the overflow tank MIN and MAX .. as long as the coolant does not go below the MIN you should not need to refill .. leave it at the MIN level ..and drive the vehicle .. see if it overflows out again .. carry a couple of litres/quarts of spare water with you just in case ... any good shop should do a compression test for you .. you could do it yourself if you rent the special compression test tool .. let me know

Thank you. I don't put in water, just 50/50 coolant. A friend looked at the car today and noticed that the coolant would be at a certain level, and then suddenly is sucked in, level sinks, a bit later rises again. The car is still not getting hot, nor does it run poorly. Temp steady, heater comes and goes (meaning blows hot and then cool, then hot again). My friend thinks this indicates a faulty thermostat. Would you think so, too? It kind of makes sense to me... Sorry to go on with this for so long, I just need to hold on to as much $ as I can and don't want to be taken advantage of by walking into a shop without a clue.

I agree with your friend .. this does sound like a thermostat sticking/stuck .. have the thermostat replaced .. and refill the coolant making sure not to get air in the system when refilling ..test drive again and see if the heat is blowing steady once the vehicle is upto temperature ! ... let me know

Hello, the thermostat was replaced. There was only a trickle of coolant in the hose connecting to the thermostat. When all was reconnected and the car was started and brought up to temp, coolant level did not change but hose felt not "pressurized." We filled more coolant directly into hose. Don't know how else to do it without "getting air into the system" as you mentioned. We looked for a valve of sorts to release possible air, but could not find it. When test-driving, temp was steady, in normal range, and heater blew hot continuously. We hope it is fixed, will be able to tell by tomorrow and more test driving. Is there a way to release air out of the cooling system, or would it have to be flushed again? Thanks again for all your valuable and friendly help.

There is no need to re-flush the system .. sounds like you have done a good job .. re-filling through the hose was a good job .. let me know if it is fully cured ..

Turn heater controls to maximum and set air discharge to instrument panel vents. Turn blower to high. Fill cooling system with 50/50 mixture of coolant and water. Pause several minutes for circulation. Start engine and allow to idle. While engine is idling, feel for hot air at instrument panel vents. If air discharge remains cool and coolant temperature gauge does not move, coolant level is low.
Stop engine and allow it to cool. Top off coolant as necessary. Start engine and allow it to idle until normal operating temperature is reached. Hot air should discharge from instrument panel vents. Coolant temperature gauge should maintain a stable reading in middle of range. Upper radiator hose should feel hot to touch. Stop engine and allow it to cool. Top off coolant as necessary. Check for coolant leaks.
Some models are equipped with a coolant level indicator light on instrument panel. If coolant level indicator flashes an additional 1.0-1.5 qts. (.95-1.42L) of coolant mixture can be added to overflow bottle.

On 3.9L engine, open engine coolant fill cap. On 3.0L engine, open air bleed located in upper radiator hose inlet pipe. On all engines, open heater air bleed located in left rear corner of engine compartment. Add coolant to degas bottle until no more coolant can be added. On 3.0L close air bleed on upper radiator hose inlet when coolant begins to escape.
On all engines, install degas bottle cap. On 3.9L engine, install engine coolant fill cap. Start engine and set heater controls to MAX heat position. Close heater air bleed when a steady stream of coolant comes from bleed during idle. Allow engine to idle for 5 minutes. Add coolant as necessary to maintain cold fill MAX mark on degas bottle.
Increase engine speed to 2000 RPM on 3.9L engine, or 1500 RPM on 3.0L engine. Hold for 3-5 minutes, or until hot air comes from heater. Allow engine to idle. Recheck to ensure hot air is still coming from heater. Set temperature control to 75°F (24°C) and allow engine to idle for 2 minutes. Shut engine off, and allow to cool.
After engine has cooled, add coolant to degas bottle as necessary to bring level to cold fill MAX mark.

Hello, wanted to follow-up. I have driven the car a few times now, and here is what's going on: The temperature fluctuates slightly, however, all in the "normal" area. There is minimal coolant leakage, just find small remnants of coolant on overflow reservoir after driving. Coolant level seems stable. On occasion, the heater will change temperature, however, it is not cold per se, but just warm as opposed to hot. Not sure if that indicates that the heater core is defective after all, or if all is fixed. Thanks for having so patiently helped me.

heat fluctuation could be due to a slight bit of air left in the system ... it is very diffficult to get all the air out of the system ... you could bleed again with the front wheels higher than the rear ..(jack up front/on a hill) as air rises as we know ... let me know

Ok,
Here is your answer!!
Your engine has built up quite a bit of waste in your cooling system. I have 2 98 and a 02 taurus' so i have had just about everything happen to me. prior to 2000 the 3.0 waterpump has an impeller that tended to rust away in the cooling system as well as normal corrosion inside the cast iron block. Most folks do not have their cooling systems flushed regularly and this debris settles in the heater core as well as the radiator and coolant resvoir. This is the reddish brown gunk in the plastic coolant tank. Ford changed the impeller to stainless post 2000 and solved the waterpump issue. You will still have to deal with the rust from the block. I found excessive amounts of this buildup in the inlet side of the heater core as well as the pump side of the radiator tank. I tried flushing but ended up replacing both heater core and radiator. At the same time i changed the thermostat just in case. No more problems! Heater works better than it ever did new! If you try to reverse flush the heater core remember to use a set of needlenose vise-grip pliers and pinch shut the bypass hose for the heater core!!