I have had very low or no heater/defroster hot air output on my 97 Taurus GL wagon (3.0 liter Vulcan with AC) since I used some Prestone Stop Leak to (successfully) control a slow loss of coolant level. I suspect the coolant loss was a due to very small head gasket leak, as there was no evidence of external leakage at the ususal suspect locations, and no smell of leaking coolant anywhere inside or outside of the car.
Back to the heater, since the Stop Leak was introduced, heat output has been very low or non existent, though very infrequently, I do get some hot air out. The engine and the rest of the cooling system is coming to normal temperature, however, the return line on the heater is cool, indiciating to me that the core is likely clogged, probably from the Stop Leak. The heater bypass hose is hot, so it looks like everything else is OK.
I am going to try to backflush the heater core through its supply and return hoses. Is this likely to clear the clogging? Assuming that it does not, how difficult is it to actually change out the core? I've done this on a few other cars, and it usually requires a massive dashboard disassembly. Never done this on a car with dual air bags.
Am I overlooking something obvious, such as a stuck thermostat? I'm thinking that's OK, based on otherwise normal coolant temperature gauge readings, and the fact that flow in the bypass line, which appears to be directly in parallel with the heater core, is hot.
Look below for a thread "99 Taurus heater problems". I flushed mine, and it has helped. I disconnected the heater core hoses, and flushed it seperately with scalding hot water from a garden hose connected to the water heater in my barn, and it helped a lot. From what my Haynes manual has on changing the heater core in a Taurus, its not a fun nor easy job. If you have the orange Dex-Cool antifreeze, get rid of it. It had turned to sludge in my Taurus, causing the heater core blockage.
Chris, I owe you a 6 pack for posting your procedure. I just followed it, minus the air compressor portion, and I have heat again in my 98 Taurus. What kinda beer do you drink?
And yes - that would be two six packs, one for the Guiness and one for the Bass! (I actually posted back before I read the rest of the replies!)
Glad to hear things worked out for you. My heater will drive you out of the car now on max temp...and it also survived another dose of stop leak to the system to clear up a persistent slow leak I have somewhere (head gasket, I suspect). I think when I did the stop leak trick a year ago, the heater was well on its way to a full clog and the stop leak was the coup-de grace. This time, no problem.
Chris Bowne wrote:
Chris, I just got an estimate of $1500 to replace the heater core and radiator on my 97 Sable becasue of a heater problem that sounds a lot like yours. I am not mechanically inclined, any chance you live in MA and are interested in some side work? I am not going to put $1500 into the Sable but would love to give your fix a try.
I'm beginning to think that this is a common problem with Tarurses. A lady I work with has a 99 Sable with the same problem. Does your 97 have the orange antifreeze? If so, its only a matter of time before its clogged again. Flush the entire system really well, then switch her to green!
It originally had the Ford orange stuff. I think the dealer changed it to green when they did the "rust in coolant" recall that added the bypass line about a year after I bought the car. I had the coolant replaced about a year ago, just after I had added the Stop Leak. The oil change shop that claimed and charged big time for a "flush" of the system nothing more than a drain and refill. That change did not fix the low heat output problem. And they re-filled the expansion tank solid, which caused a big mess when the fill cap relief valve lifted on the way home as a result. Luckily, nothing worse happened. I have been living with the lack of heat through the warm weather, but driving through the season's first snow storm the other night with a windshield that was constantly fogging up due to the lack of heat finally got me motivated to fix it right!
Chris, I owe you a 6 pack for posting your detailed procedure. I followed it, minus the air compressor portion, and I now have heat again in my 98 Taurus. What kind of beer do you drink?