Hey guys i have my heat temp. all the way up and it just blows out barely warm air..I have a new thermo. and raditor..any ideas what it cou be????

Was it blowing hot before the new components? Check your coolant level, it may be low or need to be bled.

I agree with the above, but it could also be the valve nearest the firewall the controls the left and right heat control. Sometime even if I have the settings on cold on the dash and floor, sometimes certain places will still be hot. Same thing on the other side, so maybe that diverter valve needs to be replaced.

No it had the same problem before and everything is fine..coolant is good and no air in the system..no freakin idea what it could be...heater valve??

Turn the center wheel from BLUE dot to RED dot.

Easy to overlook.

jake

If the engine is reaching proper operating temperature then it's probably the heater valve/aux pump assembly on the firewall. Or the heater core. Is the air temperature the same on both sides (driver/passenger)? Maybe it's the climate control module?

Here's a link: http://www.realoem.com/bmw/showparts.do?model=GH83&mospid=47531&btnr=64_0621&hg=64&fg=18

Like I said, the heater valve mounted on the firewall ;)

When is the last time you changed the interior filters? If they're clogged, then no air will get through.

Try this -- have the fan on full speed and have it set to recirculated air, then switch it to outside air. If you notice a significant change in speed of the air coming out of the vents then your filters are clogged.

Remove the driver side carpet on the center console, there a 3 aluminum pipes that run to the heater core, feel each pipe to make sure they are hot, be carefull they get very hot. Rev engine slightly and listen for any gurgling, sign of air in system. all pipes should be of equal temperature to the touch, when the sytem is set to full heat, if any of the pipes are not hot, rev engine and see if it helps. For interest sake there is one input and two returns. Water thru the core is determined by the heat settings that controls the heater control valve and motors in the dash that regulate temperature output mixing of the air. Also to check if under hood filter are at fault, open hood and secure the spring loaded intake flaps on the firewall to open position, this bypasses the filters.

Just to add to bmw5868's post, there are two sets of filters -- hood filters and interior filters. It wouldn't be bad to change both sets, but it's the interior filters that I think are causing your problem.

http://www.autohausaz.com/secure/PartImages/64118391385.jpg

And here is a picture of the three pipes he is referring to.

http://www.bimmerboard.com/members/davidsoine/heightofdestruction.JPG

Don't let this image confuse you, it isn't necessary to remove that much to access the pipes. Simply removing the carpet panel, like he said, will expose them so you can grab them and burn your hands.

If it turns out that your heater core is working, here is a link to buy the filters, http://www.autohausaz.com/search/product.aspx?sid=uhuvah55herwio55wvzuhm45&makeid=800003@BMW&modelid=1303254@740I&year=1998&cid=24@AC%20%26%20Heat%20-%20Climate%20Control&gid=6832@Cabin%20Air/Pollen%20Filter

Remove the driver side carpet on the center console, there a 3 aluminum pipes that run to the heater core, feel each pipe to make sure they are hot, be carefull they get very hot. Rev engine slightly and listen for any gurgling, sign of air in system. all pipes should be of equal temperature to the touch, when the sytem is set to full heat, if any of the pipes are not hot, rev engine and see if it helps. For interest sake there is one input and two returns. Water thru the core is determined by the heat settings that controls the heater control valve and motors in the dash that regulate temperature output mixing of the air. Also to check if under hood filter are at fault, open hood and secure the spring loaded intake flaps on the firewall to open position, this bypasses the filters.

Excellent troubleshooting tip, sir!

where are the interior filters? I figure i should change those out either way..and why would it be a bad idea to change out the inerior filters and hood filters??

And if thats not it..it has to be the heater valve

where are the interior filters? I figure i should change those out either way..and why would it be a bad idea to change out the inerior filters and hood filters??

And if thats not it..it has to be the heater valve

http://www.e38.org/gsussman/images/Passengers%20side%20cover%20plate.jpg

http://www.e38.org/gsussman/images/Passengers%20side%20filter%20visible.jpg

http://forums.bimmerforums.com/forum/showthread.php?t=709174

The interior cabin filters seem to get overlooked quite frequently by owners. When the climate control system is set to re-circulate the cabin air is drawn in through these filters. As far as I can tell, these filters only come into play when you're using re-circulate mode ONLY. It sounds like you're not getting any heat in any setting which would mean the interior filters probably aren't the problem. It certainly won't hurt to change them. Mine were completely plugged up when I finally found them.:rolleyes

When the climate control system is set to re-circulate the cabin air is drawn in through these filters. As far as I can tell, these filters only come into play when you're using re-circulate mode ONLY. It sounds like you're not getting any heat in any setting which would mean the interior filters probably aren't the problem.

Well, wouldn't you agree if you were drawing in the cold, outside air then the system wouldn't heat it up fast enough?

And the same is true with air conditioning -- if it's hot outside, trying to cool the outside air will do you no good.

So if he's not getting hot air for either outside air or re-circulated air, then the problem could still be just the air filters.

However, there could also be more than one problem going on here. It wouldn't be unimaginable to have both a bad heater core and bad filters.



I say, change the filters, see if that fixes it, then move on to the other possibilities.

Well, wouldn't you agree if you were drawing in the cold, outside air then the system wouldn't heat it up fast enough?

And the same is true with air conditioning -- if it's hot outside, trying to cool the outside air will do you no good.

So if he's not getting hot air for either outside air or re-circulated air, then the problem could still be just the air filters.

However, there could also be more than one problem going on here. It wouldn't be unimaginable to have both a bad heater core and bad filters.



I say, change the filters, see if that fixes it, then move on to the other possibilities.

No, I don't agree. If the heater is functioning normally it will heat up the outside air just fine. You might think you're getting more heat by re-circulating the warmer air inside the cabin but the fact of the matter remains: his heater isn't doing the job. To prove the point, remove all the filters (under the hood and under the dash) and see if the problem goes away.

No, I don't agree. If the heater is functioning normally it will heat up the outside air just fine. You might think you're getting more heat by re-circulating the warmer air inside the cabin but the fact of the matter remains: his heater isn't doing the job. To prove the point, remove all the filters (under the hood and under the dash) and see if the problem goes away.

I'll have to be honest with you, I've never used my heater -- I live in Arizona, I've never needed it.

That just goes to show you, aki82, the real solution isn't fixing your car, it's moving to Arizona. That would instantly solve your heater problem.