Long story. Here are the details:
The crisis: My sister is supposed to drive from CT to visit us in OH for Christmas.
Her car is acting up intermittently, she took it in to her service/dealer in , they spent over an hour looking, could find nothing wrong and could not make the problem occur. With an undiagnosed car problem my sister does not want to risk driving from CT to OH and back again over the holiday.
The problem with her 2006 Honda Civic XL 5-speed, 4-door sedan: The heat in her car cuts out intermittently and the last two times it did, she noticed that at the same time the temperature gauge indicated the car was beginning to over heat.
Details and background:
1) This problem began after her last tune-up in October during which the dust/pollen filter was replaced along with usual oil change.
2) Ever since, the heat has been slower to warm the car; it previously took about 3 miles driving but now 8-10 miles to warm up.
3) Her habit is to turn heat and fan all the way up when driving once she feels the heater warming the car. She usually has the heat set in the defrost and/or foot position.
A week or so ago the heat cut out and about simultaneously she noticed the temp gauge rising rather rapidly. Instinctively, she turned off the fan (opposite, she’s since learned, from what usually helps in this situation). BUT the temp gauge immediately went back to the normal zone (normal is around 9 little triangles, I think she said).
2)After a bit she turned the fan back on to just the first notch, continued driving and the problem did not recur, either the heater cutting out or the overheating.
3)She has used the heater fan in only the first-notch setting ever since.
4)A few days ago the heater cut out again and she noticed the temp gauge begin to rise, but slowly and not as high as the first time. Again turned off the fan and again the gauge returned to the normal zone.
5)A coworker offered to take a look, thought maybe the antifreeze was low and added some.
6)My sister also called the service dealer who told her to bring it in rather than wait for next scheduled oil change on Dec. 17. Fearful of a breakdown between work and the dealer – over 40 miles distance – she had the car towed in.
7) After examining the car for over an hour, including a test drive, service folks could find no problem, no leaks and could not make the heater cut out or the temperature gauge go up.
Now my sister is dives from home in CT to work in Mamaroneck NY and back in a state of high anxiety – in a less than cozy car because she can only set the fan on low and with one eye on the temperature gauge at all times.
And my anxiety level is climbing, too, because a) I know what her work drive is like and want her relaxed with both eyes on the road at all times; and b) because Christmas won’t be the same without her.
she scheduled her next oil change with the dealer a bit early so her car would be all serviced and ready for the trip to OH and will be taking it in for regular check-up on Dec. 17.
Does anyone have suggestions for what she should tell service folks to do/look for when she takes it in? She needs to know the problem has been fixed/eradicated or she won’t feel safe driving over to visit for the holiday.
Beaucoups thanks to anyone who can help us.
You didn’t say how many miles are on your sister’s 4-year-old Civic, but it’s hard to imagine there could be too much wrong with this car.
An air pocket in the cooling system could cause the symptoms you describe, but I have to assume the dealer service people would check that. Maybe not.
When her co-worker checked the anti-freeze was it low? You say he added some. Do you know where he added it (radiator or overflow reservoir)?
The slow warm-up time makes me think the thermostat isn’t working correctly. The engine should reach normal operating temperature in just a few miles.
When you say the heat cuts out, do you mean that the fan shuts off, or do you mean the fan is still blowing, but it goes from really warm air to really cold air?
My guess is one of three things:
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There could be an air pocket in the cooling system, that then gets trapped in the heater core for a while, causing the period of cold air. Best solution is to have the entire cooling system flushed, and refilled with new coolant.
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The water pump in the car might be failing. During the periods of the car not having heat, the water pump is stuck or cavitating, and that would also explain the car starting to overheat. A new water pump and cooling system flush would be the proper resolution. How many miles are on the car?
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The heater core might be partially blocked internally. This would explain the period of no warm air, and the blocked flow of coolant might cause the engine temp to rise. This would be the least likely of the three, in my opinion, but a coolant flush might give it a bit more life, and possibly clear up the blockage.
So, for the mean time, have your sister have her cooling system completely flushed, not just drained and refilled, and see how the car behaves after that.
BC.
So why is she only using the Low setting on the fan? I would use whichever setting I am comfortable with. I agree with Mcp that thermostat may be the problem, but I am missing the logic behind only using the low fan setting. Does the air consistently blow hot during these instances?
Oh, by the way, tell her she can use any fan speed she wants. It won’t make any difference.
Wow. Thanks for all the advise. I don’t know the mileage – I can ask if you think it would help, but I bet higher than you’d expect because her work drive is 80 miles round trip plus she does a lot of work related and other driving.
The coworker who added antifreeze wasn’t sure it needed any, couldn’t quite tell, and I’m not sure where he put it put he put in in carefully. Plus, from that point the car was towed to service dealer so I would think they checked antifreeze level there.
I asked her if the service folks told her exactly what they did when they checked out the car. They just told her they’d spent over an hour on it, including test drive but only charged for 1/2 hour since they found nothing.
She and I assumed checking it out included using the diagnostic machinery but we don’t know what all would be caught in the process.
I’m going to send her your suggestions about the thermostat and cooling system. I know it will help her to know something to have checked out. When you don’t know anything about cars – as we “women of a certain age” often don’t – you feel a little crazy when you say there’s a problem and the pros say there’s not. And you think they think you’re a little crazy, too!
Hi Bladecutter – It is the warm air temperature that turns cold. The fan remains on, which is why she sort of instinctively turned it off when she noticed the heat loss and the temp gauge climbing at the same time.
You and mcparadise both have the same idea about an air pocket in the cooling system. I’ll definitely tell my sister to have a full coolant flush at minimum.
As far as mileage goes, as I told mc-p, probably more than normal because of her 80-mile round trip commute and other work-related driving.
I’m not sure what things have been replaced on car so far but I’ll tell her your thoughts on the water pump along with mc-p’s on the thermostat. Could be one or both is about to go.
But shouldn’t the diagnostic thing-y (that’s tech talk for women of a certain age!) tell the techicians about the condition of thermostat and water pump?
Also, when you say “but a coolant flush might give it a bit more life” do you mean mmore life to the heater core – i.e., is it possible the heater core could need replacement, too?
Worlds of thanks – SP
I’m not sure logic has much to do with it. The first time she noticed the temp gauge climbing just as the heat in the car cut out so she impulsively turned off the fan. I’d probably do the same thing just to eliminate sound so I could think and panic at the same time!
The temp gauge immediately dropped to normal so she cautiously turn fan on to low. Everything worked fine for rest of that trip so she just kept the fan on low thinking that would help.
So the second time the heat cut out and the gauge went up it was with fan in low setting. The gauge was creeping up more slowly that time, she turned the fan off and the gauge went back to normal. When she turned the fan back on low, everything remained ok. She was on her way to work that time and when she arrived, that’s when the coworker added some antifreeze and she had the car towed to the dealer.
So for ladies like us who don’t understand what really correlates with what, turning the fan on high correlates with big jump in temperature gauge – very scary, and low fan correlates with lower/slower rise in temp gauge – scary but less so.
Probably sounds a lot more like superstition than logic to you. And it probably is! Thanks for the question. It will probably help clarify our “cars are magic” approach in pickles like this!
Mega thanks for response – SP
The diagnostic thingy won’t show anything abnormal unless the “Check Engine” light is on, and you didn’t indicate it was.
This problem requires old fashioned troubleshooting and diagnosis by a human being.
Thanks more, mc-p. I near to positive the check engine light didn’t go on. I told her I was going to post here and we went over all she could remember as carefully as we could. She would have noticed the “check engine” light, I’m sure.
Thank the powers what am for folks who can do it the old fashioned way. And that I’ve found them here. You’ve been terrific.
More thanks – SP
This all sounds to me like a sticky thermostat. No, the diagnostic computers will not know anything about a sticky thermostat or bad water pump. There are no sensors on those for it to read. A good technician could infer from other readings, like the coolant temperature sensor, that those things might be bad, but they can’t just plug in the tester and have it tell them.
It is normal for the temperature to fluctuate a little. If you are watching it closely you can usually see it drop a little when the thermostat opens and go up a little when climbing steep hills, etc. That is normal as long as it doesn’t get into the red zone or stay close to it constantly. A sticky thermostat would exaggerate those fluctuations by staying open a little too long, thus over cooling, or staying closed a little too long, thus over heating.
There is one other possibility here. It may be some sort of intermittent electrical problem. In other words the gauge or sending unit or the wiring between them has a problem. I tend to discount that idea because she loses heat, which means the coolant is actually getting too cool, or isn’t flowing to the heater core.
I do agree with the others, changing the fan speed will have little effect. In fact running the fan faster should bring the temperature down a little, not make it go up. An air bubble in the cooling system could also cause this. It would be interesting to have a real time analyzer plug in to see if the temperature gauge is tracking the coolant temperature accurately, or if it’s giving false readings. I really have a hard time seeing how the heat goes away when the temp gauge goes up, though air bubbles will cause that.
If it IS the waterpump, then she might just as well have them change the timing belt while they’re in there, it’ll save a good deal of time/money on labor. It might be due about now anyways due to mileage, depending on how much is on the odometer
“But shouldn’t the diagnostic thing-y (that’s tech talk for women of a certain age!) tell the techicians about the condition of thermostat and water pump?”
The diagnostic codes are part of the emissions control system. There is a code for the thermostat, but none for the water pump.
P0128: coolant temperature below thermostat regulating temperature
But it didn’t set, so this is not the problem