2002 Ford Taurus - Irregular Heat Temps

[maharrick]

We have a 2002 Ford Taurus 3.0L that has had a couple heater core flushes, 3 thermostats, head gasket job done and still lousy heat. heat goes from cool to medium and back down to cool. never over heating. never staying constant while running.

can anyone help me.. mark

[ricmorin]

We have a Ford Taurus, 2002 3.0l that has had a couple heater core flushes, 3 thermostats, head gasket job done and still lousy heat. heat goes from cool to medium and back down to cool. never over heating. never staying constant while running. can anyone help me.. mark

I think those are the ones with the 'H' pipe at the heater core. Very poor design. I usually pinch off the bypass portion of the hose and see if the heat increases. If it does, you need a heater core. These are famous for heater cores, and sometimes flushing is not enough. They get partially restricted and because of the 'H' hose design, coolant flow is routed around the core, not through it.

[steven kiser]

as said above i agree. i've done enough of these to know to replace the heater core. even if there is a minor restriction in the core it's enough to redirect the flow through the bypass. no you can't plug off the bypass and call it fixed. replace the core and heater hose tubes. they've been redesighned. you can flush these cores for ever and any heat increase will be minnimum at best and short lived. including the replacing of the heater hoses and coolant system flush (some of these cars need to have the plenum removed) the cost to replace them in my shop will be around 1,200.00 dollars. unfortunatly the customer will balk at this and expect you to perform a mirical. you'll bang your head against the wall trying to accomidate him with no sucess and he'll get exasperated and go to another shop. i've had people come into my shop with no heat before and it's obvious that someone has tried everything but replacing the core. i'll give the customer the replacement cost and tell them that anything else is a waste of time and money. i usually get the job.

[wbuxton]

Fords attempt at fixing the original design, which caused EXCESSIVE rust build up, resulted in poor heat output. By the original post I'm thinking you are talking about the HVAC system and not the engine temperature as indicated by the gauge? If so, I agree with the advice from the above posters.

[asample]

I have experienced a heater problem on some of these cars. It may be only the 3.0L, but the impeller on the water pump erodes away the fins and will not circulate coolant through the heater core, however, will not in most cases cause an overheating problem.

Took a lot of convincing from my tech after numerous flushes and changing thermostat to tear down and inspect water pump. The first one actually had no fins left on the impeller.

Arlin

[ricmorin]

I have experienced a heater problem on some of these cars. It may be only the 3.0L, but the impeller on the water pump erodes away the fins and will not circulate coolant through the heater core, however, will not in most cases cause an overheating problem.

Took a lot of convincing from my tech after numerous flushes and changing thermostat to tear down and inspect water pump. The first one actually had no fins left on the impeller.

Arlin

We've seen a few of those. That's why we invested in an electronic borescope. You can look right inside that pump and check the impellar without taking things apart. Best tool I ever bought!

[maharrick]

thanks everyone, why would the temp flucuate between medium on gauge and cold. it goes up and down..never over heating, in a 5 mile loop. the gauge goes through this cycle 4 or 5 times and the heat has the same maddening cycle

[ricmorin]

thanks everyone, why would the temp flucuate between medium on gauge and cold. it goes up and down..never over heating, in a 5 mile loop. the gauge goes through this cycle 4 or 5 times and the heat has the same maddening cycle

Oh, you didn't say the gauge fluctuated with the heat. If you did, sorry, I missed it. I would verify that the temp is really changing by monitoring the ECT PID with the scanner. You may have a coolant flow problem as mentioned before.

[Jeff @ Able Auto]

Sounds like trapped air. Do you have a vacu-fil? Saves tons of trouble. If ya can get ur hands on one I would try that.

[steven kiser]

ok, now that new information is in the mix i have to ask a few questions. how is the heat coming from the vents? it should be almost scorching. tou say the temp goes from medium to cool. please be more specific. if you're relying on the dash guage please don't. in cases like this it can be very misleading. use a scanner and read temp through it. if the radiator was replaced and a high flow one was installed that in itself would cause a varied temp reading. if temp remains constant while driving (in the normal range) see if the flucuation at idle correlates with the fan coming on. you may be keying in on the guage because you feel that the climate inside the car is too cool. a lot of work has been thrown at this car. i need more of why and when's to be more of a help. if it's been a comfort issue inside the car the heater core should be replaced along with the tubes. if the temp guage reads in the normal range then it's normal. i've seen many customers become consumed with guages being "incorrect" all because they've started paying attention to them because of a major repair. ever have a customer come in complaining of their mileage being off after spending 800$ on a major tune up and 02 replacement because the check engine light came on? the first thing i'll ask is what was it before? i've gotten "i don't know" as answers. now, ive found they're comparing it to price not mileage or a graph. i had customers come in complaining that it was costing way more to fill their tank than before it was tuned. the price of a gallon of gas had jumped 1$ a gallon between fill up's. if the car had come in for a blown head gasket (hate to tell you but it could have been a cracked head in this engine) you replaced the gasket and have good heat and the only issue is the guage flucuating within the normal range while at an idle then the "normal" reading may infact be "normal". you may be having an air pocket issue around the t/stat housing. if this is happening time and time again either the head is warped or cracked. that liquid head gasket repiar from barz leak seems to work on occasion.

[Tim Martin]

I have also seen most of the issues already mentioned. The most common problem has been the heater core. If the temperature gauge is fluctuating back and forth it seems fairly safe to eliminate the water pump as the source, no discredit to the techs that have seen impeller blades gone, I have also seen that but in those cases the coolant flow is consistent just slow. Another issue I have seen is coolant temp sensors out of calibration and will not turn the radiator fan on at the proper temp. I would agree, ya cannot rely on the dash gauge for diagnosis in this situation, although that should be fairly accurate. These cooling problems are difficult to solve. Another thing I have done in a few is when replacing the thermostat if the stat does not have a relief hole in the top of it, I take a very small drill bit (1/8") and make a small hole for air to escape. This allows only minimal coolant to bypass the stat while still allowing for engine warmup. I use my AirLock to fill these cars with coolant. Works real well.

[steven kiser]

i'll use air lock to fill these as well. another little thing i do is on occasion i'll stick a tylenol caplet in the t/stat to keep it open. it fills quick and will circulate right away to bleed any air out. then it dissolves.

[Stewart Levy]

Steve will a assprin do the JOB?

[maharrick]

MY TECH HAS READ ALL THE RESPONSES AND WANTED ME TO CORRECT A COUPLE THINGS I SUBMITTED. VEHICLE HAD A BLOWN HEAD GASKET ORIGINALLY AND FAILED THE CO2 TEST. AFTER BLEEDING, COOLANT GAUGE IS STEADY WITH GOOD HEAT FOR A FEW DAYS, THEN FLUCUATES. TECH THINKS THE MACHINE SHOP MISSED A CRACKED HEAD. GASKET DIDNT LOOK BAD. THE CAR WAS A CRONIC NO HEAT. WE HAVE FLUSHED AND REVERSE FLUSHED, PUT WATER PUMP AND DONE THE HEATR CORE BYPASS. I THINK WE ARE GOING TO TEAR DOWN MOTOR AGAIN. MARK

[steven kiser]

that's the biggest reason i use alabama cylinder head. i've seen cracks in these heads where i never thought one could be. you may want to try that barz leak head repair kit. i've seen it work.

[fortknoxx]

well, what did you come up with?