99 E38 not blowing hot air from vents

[masangya]

99 E38 not blowing hot air fr vents. set the IHKA to 90 degress , set the ctr dial inbetween the ctr vents to hot. recently repl rad , thermo n bleed system . any thoughts?

[meteck]

There's a lot to check, but I would start with the fuses especially those that control the heater control valve.

[bmwbob89]

They don't blow hot air from the center vents. It puts you to sleep. If you get hot air from the floor and defrost it is working as designed.

[pizzaman09]

They don't blow hot air from the center vents. It puts you to sleep. If you get hot air from the floor and defrost it is working as designed.

?? Both my 98 e38 and now 01 e38 would blow hot air from the center vents.

Oh, hey 4,444 post! hehe

[Edwin NL]

Check your heater valves, the center vent generates warm or cold air by driving

[bmwbob89]

I did not mean you get no heat from the center vents. You get warm air but usually not really hot air on the drivers side. Once the cabin is heated up there is no need for it and it does put you to sleep.

[audiavant]

q Q........and some manual pics ;-))

[mpower5266]

I have the same issue but with no heat from anywhere?

[miylive]

welcome all to the no heat club!

I am but a sailor in the same boat! no heat since onset of winter(

my quest for a HCV is still on - I get heat on the passenger side but cold air on drivers...

want to try a T hook up to replace the HCV - anyone ever tried this - ? would it be better to use steel or a plastic pipe for this ?

for all those clueless people - its usually the HCV

[mpower5266]

Is there anyway to test the heater control valve? Also I seem to be losing coolant but I dont have a leak that I have found. The whole cooling system is new and intalled this summer, I didnt lose any coolant until I started to run the heat.

[masangya]

some1 mentioned 2 ck the aux water pump 2 c if it is pumping coolant into the heater core.

[getty58840]

They don't blow hot air from the center vents. It puts you to sleep. If you get hot air from the floor and defrost it is working as designed.

Is this true bmwbob I used to get hot air from my vents and all of a sudden I only get it from the floor and the defrost. Unless I am mistaken

[RIboater]

welcome all to the no heat club!

I am but a sailor in the same boat! no heat since onset of winter(

my quest for a HCV is still on - I get heat on the passenger side but cold air on drivers...

want to try a T hook up to replace the HCV - anyone ever tried this - ? would it be better to use steel or a plastic pipe for this ?

for all those clueless people - its usually the HCV

I"ve got a T in place of the HCV now, but I haven't put the rest of the cooling system back together yet to try it. Won't until probably Friday night or Sat. I'm using plastic because it's a temporary repair to test the theory on this. As amazing as it sounds, getting at the HCV is easier on the V12 than the V8. It's located on the shock tower near the oil filter, sort of, wedged in between the engine. Very easy access. A small miracle on this car.
I had another small plastic Y connector let go last week and lost coolant. I replaced it with brass. It was where the expansion tank hose, a water pump hose and a hose from the top of the engine that come together just under the oil fill cap on a V12 for those curios.

[miylive]

I"ve got a T in place of the HCV now, but I haven't put the rest of the cooling system back together yet to try it. Won't until probably Friday night or Sat. I'm using plastic because it's a temporary repair to test the theory on this. As amazing as it sounds, getting at the HCV is easier on the V12 than the V8. It's located on the shock tower near the oil filter, sort of, wedged in between the engine. Very easy access. A small miracle on this car.
I had another small plastic Y connector let go last week and lost coolant. I replaced it with brass. It was where the expansion tank hose, a water pump hose and a hose from the top of the engine that come together just under the oil fill cap on a V12 for those curios.

Excellent - thanks for the info, I'll be more confident to try this once you have your results out!

keep us posted and also tell me the diameter of the T to be bought, the pipe size dimensions and material, im also thinking brass would be better than plastic - or even steel may work.. just curious of whether there is a need to push water up through the pipes or does it just flow there by itself as through a fluid motion once the engine starts?

about the aux pump - i am of the reasoning that it only "pumps" when the car is off - hence the REST function.. correct me if im wrong?!

another small ask if I may ...pics of the mod please as Ill be more confident doing it once I have all the data/info I need....thanks in advance!

about where the HCV is in he v8 - lol .. no comments on this one :p .. why do you think I have been putting this off for so long:p

[Her740]

about where the HCV is in he v8 - lol .. no comments on this one :p .. why do you think I have been putting this off for so long:p

The HCV is on the drivers side firewall, directly behind the left valve cover. Access is not bad if you do decide to replace it. It's a matter of removing three hoses and two electrical connections. The unit just lifts straight up and out. Use my screen name to do a search for recent posts. I did a write up on R&R on it and where I bought it. HTH.

Sean

[Qsilver7]

Is this true bmwbob I used to get hot air from my vents and all of a sudden I only get it from the floor and the defrost. Unless I am mistaken

Because you haven't clarified what position your stratified air dial is in...we are obliged to suggest the simple things first...check if you have it turned to the blue or the red. If you've done this...then let us know so that we don't frustrate you with suggestions that you've already tried.

The dash vents (and vent at rear of center console) can be "tempered" warmer or cooler based on the position of the dial...note that they have red & blue arrows intimating they can be tempered:

The stratified air wheel allows the driver to "temper" the air from the dash vents:

[masangya]

i moved the dial in the center of the center vents to red(hot). im suspecting the HCV.

[bmwbob89]

I am telling you they don't blow hot air, Warm only. Somewhat hot when the car/cabin is dead cold. I've been dealing with this complaint since 1989 when the E34's started to use this system. I've seen techs spend countless hours trying to fix what ain't broke. When the cabin is cold you get some heat out of the center vents. Why do you want heat there anyway? If the cold air coming in bothers you close the vents. They let some cool air in on your face to keep you awake.

If you have good heat on the floor and defrost the heater valve is fine. The auxiliary pump is only needed at idle and rest function.

[RIboater]

If you have good heat on the floor and defrost the heater valve is fine. The auxiliary pump is only needed at idle and rest function.

So this aux pump should be running with the car just sitting in the driveway? It doesn't. Haven't tried it using REST. I don't have good heat unless I rev the engine.

[bmwbob89]

See if it has power going to it. If it does it should be running. If you have poor heat at idle I would suspect it's inop. You should be able to put a long screwdriver on it and put the other end in your ear and hear if it's running. It's a cheap stethoscope. even if it does not work I don't think I would spend that much money on a new heater valve to fix it. I am not at idle that often.

[RIboater]

I have a "T" where the HVC should be. I have the HVC off to the side with the two electrical plugs connected. I can visually see the pump is not running and the valves don't close. I'm not sure when they should and how to make them is the problem.

[bmwbob89]

My wife has a suggestion. We just had the defrost on to clear the windshield and she said if they want to cook their face off just put the defroster on. I agree.

[masangya]

cust say s does not blow hot fr def n floor vents.

[bmwbob89]

Hey Masangya what the heck are you trying to say. Speak English not text.

[masangya]

customer says , does not blow hot air from either defroster or side vents/floor (not center).