Help with a Non Mopar car cooling problem..............

[bandit67]

Hi Guys, would love some input here , if possible. My Mom calls me and said her 96 3.0 Ford Taurus has no heat. Her local repair shop says she needs a heater core and it will be 500 bucks to change out.  I said hold off , let me look at it. I found the coolant low, fill it up , and began driving across the state home. I got heat , but the temp gauge swings from normal engine temp down to cold and back up all the way home, a three hour drive.  I changed thermostats and flushed out the heater core, had heat , but the temp gauge still swings up and down.  Installed a heavier duty thermostat and tried to flush out the radiator. Took the car for test drive, motor overheats and no heat from inside.   Installed a brand new radiator, re flushed  motor, all lines and heater core again, and now have heat inside, the motor heats up to normal temp, the fans come on when they should , BUT, the temp gauge still swings from normal down to cold and back up again as I drive. The car has 118,000 miles on it and I think the water pump is fine   Have not changed out the temp gauge sending unit , but did remove it to check for any corrosion or crud. There are no engine computer codes or anything else I can find abnormal...........any ideas..........thanks......J

[RD]

sounds like the temp sending unit has gone haywire and has no relation to your heating problem.  replace it and check it out to see if the gauge works.  I believe fords have two units (at least my 93 ford escort did) when it came to the coolant, one for the gauge and one for the fans to kick on and off.  sounds like the one to the gauge is tits up.  but, this is not my forte, as its a forde and not a MOPAR! hehe

[bandit67]

Thanks, Rd, I will change out the temp sending unit.........but I do not think that is the culprit.  I mean when the cooling fans come on, the temp gauge shows high temp and settles down to normal  quickly.  In looking at the system the fan sensor and temp switch  seem to be in line with the coolant flow coming from the heater core. I think I can bypass the core and put coolant flow straight from the water pump to both sensors.  If the temp stays constant, that would mean there is something causing the flow in the heater core to change........some kind of a restriction.........maybe.......

[RD]

if that is the case, just remove both heater hoses to the heater core and blow some low pressure air reverse of the flow to blow out any blockage.  I did that on my 93 escort and voila!  heat again.

[chgr500]

Hi Guys, would love some input here , if possible. My Mom calls me and said her 96 3.0 Ford Taurus has no heat. Her local repair shop says she needs a heater core and it will be 500 bucks to change out.  I said hold off , let me look at it. I found the coolant low, fill it up , and began driving across the state home. I got heat , but the temp gauge swings from normal engine temp down to cold and back up all the way home, a three hour drive.  I changed thermostats and flushed out the heater core, had heat , but the temp gauge still swings up and down.  Installed a heavier duty thermostat and tried to flush out the radiator. Took the car for test drive, motor overheats and no heat from inside.   Installed a brand new radiator, re flushed  motor, all lines and heater core again, and now have heat inside, the motor heats up to normal temp, the fans come on when they should , BUT, the temp gauge still swings from normal down to cold and back up again as I drive. The car has 118,000 miles on it and I think the water pump is fine   Have not changed out the temp gauge sending unit , but did remove it to check for any corrosion or crud. There are no engine computer codes or anything else I can find abnormal...........any ideas..........thanks......J

[chgr500]

Hi Guys, would love some input here , if possible. My Mom calls me and said her 96 3.0 Ford Taurus has no heat. Her local repair shop says she needs a heater core and it will be 500 bucks to change out.  I said hold off , let me look at it. I found the coolant low, fill it up , and began driving across the state home. I got heat , but the temp gauge swings from normal engine temp down to cold and back up all the way home, a three hour drive.  I changed thermostats and flushed out the heater core, had heat , but the temp gauge still swings up and down.  Installed a heavier duty thermostat and tried to flush out the radiator. Took the car for test drive, motor overheats and no heat from inside.   Installed a brand new radiator, re flushed  motor, all lines and heater core again, and now have heat inside, the motor heats up to normal temp, the fans come on when they should , BUT, the temp gauge still swings from normal down to cold and back up again as I drive. The car has 118,000 miles on it and I think the water pump is fine   Have not changed out the temp gauge sending unit , but did remove it to check for any corrosion or crud. There are no engine computer codes or anything else I can find abnormal...........any ideas..........thanks......J

Does your car have a coolant bypass kit currently installed? ..If by-pass kit was NOT previously installed, install Coolant By-pass Kit (F7DZ-8522-AB) OR (METHANOL VEHICLES F8DZ-8522-CC), new Water Pump (1F1Z-8501-AA, Motorcraft PW-404)
 
There are alot cooling system concerns with these engines...water pumps fail with the impeller spinning on the shaft..depending upon speed...96-98 Taurus / Sable ...there was a lot of casting sediment concerns also with the early 3.0 litre ...there were chemical flushes as well as a reverse flush procedure including removing a core plug on each bank to help the tech get rid of sediment from engine block casting......plenty would come out for a new car at the time....would also plug up the cooling system components....most 3.0 litres always have rusty looking coolant....Be sure the coolant is topped up proper..
.
NOTE: IT IS RECOMMENDED THAT THE COOLANT CAN BE SAFELY FILLED TO THE TOP OF THE CLEAR PORTION OF THE BOTTLE (WHEN THE ENGINE IS COLD) TO PROVIDE EXTRA RESERVE COOLANT

So if all else looks fine on your car...go get a water pump...everything else is new....you now have heat because the poor flow can move a bit better?....makes sense with a slipping impeller at highway speeds and a fluctuating temp gauge, but all the way to cold....hmmmm...you always have heat from the registers when it does this?  there is no coolant loss? monitor coolant level with the engine cold...without the bypass kit the engine likes to air lock the cooling system when refilling...would also fluctuate the gauge , no heat from vents and eventually will overheat...  head gasket can also fluctuate the gauge...airate the cooling system then bleeds off the air....should also loose heat from vents and have coolant loss....aerated coolant will cause gauge fluctuating...no heat from vents......might want to test the gauge and sender...if you currently don't have any other concerns except with the gauge???.....good luck

[Tilar]

I don't know if it applies to Ford, But my Chevy has 2 bleeder valves to bleed air out of the cooling system. When I bought the car, the guy was having overheat problems and it turns out he had just had the cooling system flushed, and the guy that did it didn't know you had to bleed the system. I did end up having to have a head job done on the car because it had a heat crack in one of the heads.

[bandit67]

Thanks Chr500, just what is a coolant bypass kit and where does it go. Never have heard of one. The gauge does not drop down to the exact cold level , but almost, and then rises to normal. I will pull the water pump and change it. The water pump outlet goes straight to the heater core and I wondered how to check for correct pressure, which would indicate if water pump impeller had failed.  I have flushed heater core using water hose pressure BOTH ways and did not notice any restrictive flow either way. I have not noticed any coolant loss since installed new radiator. I also have always had heat from heater core since rad change out.   I always drill a small hole in any thermostat I install and thought  that would help prevent air in system.  But , IF head gasket is leaking pressure into coolant system ,,,,,not sure how I could tell this.
          As to pulling core plugs in order to clean out block of crud, I have never looked at this.  But will. I do this on ALL v 8's in which I am trying  to service.              Thanks for all the input...........the knowledge from folks here on this site is unmeasurable.......John