[cband]

Hi Guys,

I did 800 highway miles yesterday, with some fine snow, and average temp of -5F. Snow was everywhere... door jams, underbody, i think even around the transfer-case as it was making a noise too. So I went to the car wash an melted as much snow as possible, most the snow was gone, transfer case / axle seemed normal again and all was good.

parked the car outside, and then noticed that heater blower would not blow air out any vents. Also noticed fan for radiator was not spinning. KTMP-MOM is getting up to 96C at idle on driveway this morning and fan will not come on.

Coolant looks good. hoses are warm up top. I can see heat, more than normal coming off the grill.

No dash codes and no codes in INPA.

any suggestions?

I am trying to find a garage today to let the car get completely melted and dry at 50 degrees.

[Nordkeyz73]

Blower motor.

[cband]

so went for a drive... little triangle ! light came on (same as the one for low on gas), then when I shut off car the oil can light flashed. Car has been in garage for 2 hours and melting but blower still doesn't turn on.

radiator was hotter on the top than the bottom.

So I am still confused... blower and water both not working? any fuses to check.

INPA still give zero codes.

[Taskmaster]

Pull codes again.

[cband]

no codes... radiator is hot on the top cold as ice on the bottom... Coolant is not circulating.... has to be the thermostat or the water pump or a sensor controlling them.

Going to get the car completely above freezing overnight in garage.

then I can run the water pump circulation cycle to test the pump.

not sure how to test the T-stat?

also hoping the blower runs again because it seems that there are either two issues... unless they are related somehow else?

could there be a bad fuse?

[SDemetris]

Originally Posted by cband

no codes... radiator is hot on the top cold as ice on the bottom... Coolant is not circulating.... has to be the thermostat or the water pump or a sensor controlling them.

Going to get the car completely above freezing overnight in garage.

then I can run the water pump circulation cycle to test the pump.

not sure how to test the T-stat?

also hoping the blower runs again because it seems that there are either two issues... unless they are related somehow else?

could there be a bad fuse?

dude.. thats how your radiator works. by the time the coolant gets to the bottom, it cools off- especially when its that cold outside. t-stat and water pump are the same in our car anyways so you can just replace them together if theyre actually bad.. but it does sound like a blower motor to me

[MarkkyyMan]

Heat rises.

[JustinGTP]

Thermostat? Water pump? Blower Motor?

[mike3000fl]

Is the blower fan blowing air at all? Does the display show any bars?

the blower fan (the one for the AC vents) should work no matter what the waterpump/thermostat/radiator are doing. It is electric and should blow air out the vents when you ask it to (it just may not be hot or cold but it should still blow). There are certain situations when the car shuts off the blower fan if the electrical load is too great though.

If the blower is not blowing, then you should work on that, it removes easily under the passenger dash kick panel, takes 15mins tops.

If it is blowing, but not blowing hot, then you may have a clogged heater core, or a bad waterpump, or a stuck open thermostat causing the car to never really heat up and send hot coolant to the heater core.

When my waterpump went out, it went out at random times, then started working again later with a restart, anyways my point.. i could always tell when it had stopped working because my car would stop blowing warm air due to the lack of circulation of coolant. Perhaps this is your issue too. I like the idea of testing the waterpump using the vent procedure where you hold down the gas pedal (you can find this in some of the coolant flush DIYs).

There are also activations in INPA that allow you to run the radiator fan and the waterpump I believe, in order to test them, you can also turn on the blower fan at different speeds from INPA.

[SDemetris]

That is conplete crap. Your heater will not stop blowing hot air if the water pump breaks.

[stormtrooper7]

I could simply be seized. That's what was happening to mine last year. There is a DIY/How-To on this somewhere...

But if you remove the cabin filter cowel and look down into the vent on the passenger side you will see the blower. Grab a long stick or something and give that a spin to see if it starts moving. I gave mine a shot of WD-40 and it's been fine ever since. This will take you literally minutes.

[mike3000fl]

Originally Posted by SDemetris

That is conplete crap. Your heater will not stop blowing hot air if the water pump breaks.

Yes it will. I have been there and done that. The coolant wont circulate to the heater core. If the coolant magically circulated, then it would magically go thru the radiator too and the car would not overheat, but we both know cars overheat when the waterpump goes out. Using your (lack of) logic, if the coolant magically can flow thru the heater core when the waterpump dies, why can't it magically flow thru the radiator also? please tell me. According to your logic cars should not overheat because there is some magic force keeping coolant moving thru the radiator and heater core.

You clearly don't understand how a heater core works chump, its a small radiator, air passes thru and gets warmed up, this process removes heat from the engine, it moves it to the outside air and with the heater core it moves it to the cabin.

It's very basic, the thermal energy from the combustion process is moved to the coolant, through conduction, the hot coolant is then pumped to the radiator where the thermal energy is then transferred to the air passing thru due to the surface area of the fins on the radiator. This process of moving heat to the air, takes the heat away from the engine. Without a pump to circulate the coolant, this process cannot occur and the engine keeps the heat and overheats.

The very same process happens with the heater core, it is a small radiator that cabin air passes thru. It takes hot coolant from the engine, and that heat is transferred to the cabin air. Without water pump circulating the coolant, the heater core will not receive hot coolant, and will not be able to heat the cabin air as it passes thru.

the car can't blow heat until the engine is warmed up in the morning, that is because the coolant carries the heat to the heater core and the coolant is still cold, once the coolant is hot you can get heat. Think about this jughead....If there is no waterpump to pump it around though, then there is no heat. You can't magic heat from nowhere, there is no heating element that glows red like in a toaster oven, the heat must come from the coolant, and that hot coolant must be pumped to the heater core from the hot engine, otherwise no heat comes out the vents, you simply can't magic hot coolant to the heater core without circulation, and that my stupid friend is what the water pump does, it pumps.

Like i said, i have been there and done that. I am talking from experience, not out of my ass. When my waterpump started to fail, it would go out once a week or so, then it increased to almost every trip that I drove the car. I think that it had an electrical issue and the DME would shut it down. All I had to do was restart the car and it would work again. I used to monitor the engine temp with the hidden menu, and then restart when I saw it get near where the yellow light comes on. I noticed that when the waterpump would quit, the heater core would quit providing heat thru the cabin vents, as in the air would suddenly blow cold until i restarted it. I went thru this for months so it is not something I am imagining. As soon as I the waterpump would kick in again, I could get heat.

Not saying the waterpump is the problem on this guys car, but if the blower is blowing air, and that air is not hot, then the somewhere along the line that heater core is either dry, clogged, or not getting hot coolant pumped to it. Or the air mixture blend flaps stepper motors have failed.

[cband]

Thanks everyone... Very good comments.

Car had been in friends garage for 16 hours. My friend tested bblower last night and it is blowing air again. I am heading over there soon and will test water pump and fan with INPA.

It got even colder here. -45F. Sidenote: this last week I drove 3400 miles from WI to Fairbanks Alaska. The car was a champ on highways and in Canada but it was 20-50 F with warm temps / ice there, so completely different conditions. I highly recommend Nokian hakkapeliitta 8 studded tires... Would not have made it without it. I intended to do an ALCAN post soon. Very thankful that I had no issues until I got to town.

I'll post later today if everything is running normal or not. I'm hoping it was just a stuck blower and frozen pump/thermostat. I am quite sure I had overheating because of dash light, coolant temp mon running in upper 90s C.

Car is running 0w40 synthetic, has battery tender, and oil pan heater. Car ran fine in -22 WI cold spells.

[SDemetris]

The heater core is right behind the engine. Therefore it will always be hot.. Why do you think everywhere tells you to put on your heater full heat and fan speed when your car overheats? Its not as effective as liquid cooling, but it makes a difference because the core is so close that there is significant heat transfer to it though the air in the engine bay...

[cband]

did water pump air vent cycle test -- passed
put car in accessory mode -- defrost button works normal
tested blower in DIS... works great.
cabin air filter looks good, no blockage
no codes in INPA relating to these issues.

dare I go for a drive at -38?

I bought new blower and will replace because mine is old and could be intermittent... will install this weekend.

[mike3000fl]

Originally Posted by SDemetris

The heater core is right behind the engine. Therefore it will always be hot.. Why do you think everywhere tells you to put on your heater full heat and fan speed when your car overheats? Its not as effective as liquid cooling, but it makes a difference because the core is so close that there is significant heat transfer to it though the air in the engine bay...

The part in bold is absolutely the stupidest thing i have ever read on here. A heater core is absolutely liquid filled (coolant) and the heat from the engine is not transferred to the heater core thru the air, that is just silly. Heat from the engine moves to the heater core by way of hot coolant being pumped to it.

You don't know what you are talking about. It does not sit behind the engine, it is in the dash, you have to remove the dash to change it out. Get a service manual and read it. It doesn't get hot unless hot coolant is passing thru it. That's just how it is, sorry that you are wrong, but someone has to be. And when you say that it is not as effective as liquid cooling, you are retarded because it is liquid cooling, there is liquid coolant running thru the heater core, it is a small radiator. People even get heater core leaks, and the passenger compartment will smell like coolant, google it, your ignorance is amazing.

And of course turning on the heat helps cool an overheating car, ON A NORMAL CAR WITH A BELT OR GEAR DRIVEN WATERPUMP. On a BMW the waterpump is electric, once it is dead, it is dead and no coolant circulates, so you cant remove that heat from the engine by turning on the blower fan and setting it to heat mode. Simple physics. How can heat move from the engine, to the heater core, if the pump isn't moving the coolant, think about it, the coolant is the medium that transports the heat. Think of the coolant as a conveyor belt carrying heat. The conveyor stops when the waterpump dies, so the heat stays trapped in the engine, it can't move to the radiator OR the heatercore, the conveyor stops moving it anywhere. If it could still move coolant to the heater core when the pump dies, then the same dead cooling system would also allow coolant to pass thru the radiator and cool the engine as air passes thru the fins, but IT DOESN'T and the proof is that the car overheats. Simple physics.

Heres another one for you genius, lets say your body's heart stopped beating (your body's waterpump), can your blood still flow and carry oxygen to your brain? Of course not, your brain dies. Same thing here, the heater core can't stay hot with no hot coolant passing thru it if the electric waterpump has died. Blood and coolant are both mediums that carry things to other parts of the system. If the pump stops, then the conveyor belt stops.

Heres another interesting fact. Why does BMW put an auxillary water pump in the car..... So you can use the REST feature when the engine is not running. The car has to move the coolant to be able to create heat. If you could use the REST feature without pumping coolant, then they would not have needed an auxillary water pump. Read about it here genius.... http://www.bimmerforums.com/forum/sh...ary-water-pump

Page 640-12 of the bentley manual also confirms that the waterpump MUST run to create heat while in REST mode....
"Residual heat (REST) function allows hot or warm engine coolant to heat up vehicle interior when engine is not running . This function is available for a run-down period of approx. 15 minutes from the time ignition is switched OFF (terminal 15 OFF).
Pressing REST button signals EGM via bus system to activate electric coolant pump and circulate coolant."

So there you go, you can't have heat without moving that hot coolant to the heater core. So please go play with your toys and leave the grown ups alone.

[shadow191]

Heater core is where it is because it's between the engine and the cabin. They could put it other places and it would still work fine, it's heated by coolant, not air. If you change coolant on a car and don't bleed the system correctly, you can get air trapped in your heater core. When that happens, your heater will blow cold air, it's happened to me. Air has nowhere near the heat carrying capacity of liquid.

On cars with belt driven water pumps, you turn the heater on precisely because coolant circulates through the heater core. It provides another way to exchange heat, it's blowing it into your cabin. I've owned cars with aftermarket turbos and the OEM radiator wasn't sufficient sitting in traffic because the surface area wasn't enough and the fan wasn't powerful enough. Turning the heater on gives the coolant another place to go and it can shed some heat through the core. It's not much though.

Water transfers heat something like 25 times better than air does. A 70 degree day feels pretty nice. 70 degree water is freezing (you can even get hypothermia if you stay in it long enough).

Originally Posted by SDemetris

The heater core is right behind the engine. Therefore it will always be hot.. Why do you think everywhere tells you to put on your heater full heat and fan speed when your car overheats? Its not as effective as liquid cooling, but it makes a difference because the core is so close that there is significant heat transfer to it though the air in the engine bay...

[bimmerquick43321]

I could be wrong, but no one sees the connection, cold temperature versus car wash, versus a fan not turning? Probably small water infiltration, fan got stuck, now all is good...

makes me think of my first car, same issue but a little bit worse, had to heat the engine quite a bit before it would start, problem is that I was always late in the morning to go pick up a friend in way for university, so long story short, after he got in a few lights later, once the car got a little bit warm, at red light, I pop the hood, he gets out, starts punching the heater fan like crazy, starts working, I give him thumbs up, gets back in car, light turns green, nothing to see lol

[cband]

I think it was water or moisture in the system.

Been working great all day until I parked it in cold for 30 minutes. Turned it on and fan didn't blow again... Pushed a few buttons and then a rush of air ccame.

How many flappers and things are in the way of the air flow? I think it could also be some vent is shutting stuck causing the air not to flow. I am replacing the motor and would like to lub the flaps if it easily accessible.

[stormtrooper7]

cband, did you see my post? Your issue sounds exactly like mine. The shaft for the blower is probably rusty and takes a bit to start it turning (hence when warm it works). Take the 10 minutes and try what I suggested.

[cband]

Originally Posted by stormtrooper7

cband, did you see my post? Your issue sounds exactly like mine. The shaft for the blower is probably rusty and takes a bit to start it turning (hence when warm it works). Take the 10 minutes and try what I suggested.

Yes I looked down the vent. It was rusty. So I sprayed wd40 at it. Kind of hard to shoot it in the right spot and you only hit the top nut, not the whole shaft. Replacement comes tomorrow.

[stormtrooper7]

Originally Posted by cband

Yes I looked down the vent. It was rusty. So I sprayed wd40 at it. Kind of hard to shoot it in the right spot and you only hit the top nut, not the whole shaft. Replacement comes tomorrow.

I just taped a few of those little red attached nozzles together to get down there. But if you have replacement coming then just wait for that...cool air is good for you anyway (in moderation of course)