No heat, some warm...on one side.

[Her740]

2000 740i. Took a little trip yesterday and back home today. On the way out, seemed pretty warm on drivers side, wife complained of no heat on passenger side. On way home today, blowing cold on passengers side and kinda warm on drivers side. Settings on auto, tonight, my wife had hers set to like 87, mine was at 80 and fan speed setting did not seem commensurate with fan speed.

I searched and saw a few similar problems. Most of the responses were, "Me too". A little help to narrow this down would be appreciated, TIA.

Sean

[Edwin NL]

Sounds like your heater valves (water valves)are gone

[skipv]

Ditto on the heater valves. Also check to see that they are not corroded. If so you may want to consider flushing the system and refill with BMW approved coolant. If you do the job urself it is a PITA and I would advise replacing the hoses.

[stas2007]

x3 on the heater valve; most mechanic shops have a special gun that they put to next the heater hoses next to the firewall to check the temperature or smth; that should tell more about the problem; another possibility is your thermostat-i had no heat when mine went-check if your lower radiator hose is cold after driving for 15 minutes, if it is its your thermostat.

[RIboater]

My lower hose is much colder than the top even after putting in a new t stat a month ago and new water pump a year ago. And the engine temp never goes above 110c. I seem to have heat but the hose being cold bothers me. The 3 hoses on the valve are hot.
There is circulation as I see a steady stream from the bleeder valve overflow into the expansion tank with the cap off.
What's up with my lower hose? Is the radiator THAT efficient?

[novasol]

My lower hose is much colder than the top even after putting in a new t stat a month ago and new water pump a year ago. And the engine temp never goes above 110c. I seem to have heat but the hose being cold bothers me. The 3 hoses on the valve are hot.
There is circulation as I see a steady stream from the bleeder valve overflow into the expansion tank with the cap off.
What's up with my lower hose? Is the radiator THAT efficient?

Did you unplug your aux water pump like I said to on your other thread?

[Her740]

Wow, well thanks for the quick replies. Water pump/thermostat is a little over a year old, hope that wouldn't be the problem. Replaced the heater hoses late this summer when one had a split in it. where are the heater valves located?

OH CRAP...it's not that secondary water pump thing is it?!?!?! That's like $400!

Sean

[RIboater]

Did you unplug your aux water pump like I said to on your other thread?

I did but what am I looking for now? That's not going to make my lower hose hot is it? I just dont' understand with a brand new thermostat why that lower hose remains cold. The upper is hot and hard, lower is luke warm and mushy. My temp on the OBC never goes above 110c so the engine is getting cooled somehow.

[KJLegend]

I'm having similar issues.. I checked my bottom hose and it was cold after driving across town (15 minutes highway).

Is this a for sure thing that its my thermostat? Any major problem that it may have been like this for a while?

[novasol]

I did but what am I looking for now? That's not going to make my lower hose hot is it? I just dont' understand with a brand new thermostat why that lower hose remains cold. The upper is hot and hard, lower is luke warm and mushy. My temp on the OBC never goes above 110c so the engine is getting cooled somehow.

Do you get heat in the cabin with the secondary pump unplugged? If not, then your car is not circulating coolant through the system properly...the water pump in these cars is usually sufficient to get heat to the cabin.

[Edwin NL]

Why not change the heater valves?

[RIboater]

I could change the heater valve/motor but how would that solve a cold lower hose?
I'll try a three way connector to eliminate it first.
Seems like the radiator is the block. I see a steady stream from the pee hole with expansion cap off so something is flowing. I think I saw the PO had changed it before 55k in the pile of paperwork. Could it be completely blocked?

realoem.com shows there are two heater valves but not where the second one goes. For a V12 anyway...
http://www.realoem.com/bmw/showparts...=64&fg=18&hl=3

[miylive]

I could change the heater valve/motor but how would that solve a cold lower hose?
I'll try a three way connector to eliminate it first.
Seems like the radiator is the block. I see a steady stream from the pee hole with expansion cap off so something is flowing. I think I saw the PO had changed it before 55k in the pile of paperwork. Could it be completely blocked?

realoem.com shows there are two heater valves but not where the second one goes. For a V12 anyway...
http://www.realoem.com/bmw/showparts...=64&fg=18&hl=3

do let me know how the 3 - way connector goes.. ive been dying to try that as I have a blown HCV that only works on the passenger side!

[novasol]

I could change the heater valve/motor but how would that solve a cold lower hose?
I'll try a three way connector to eliminate it first.
Seems like the radiator is the block. I see a steady stream from the pee hole with expansion cap off so something is flowing. I think I saw the PO had changed it before 55k in the pile of paperwork. Could it be completely blocked?

realoem.com shows there are two heater valves but not where the second one goes. For a V12 anyway...
http://www.realoem.com/bmw/showparts...=64&fg=18&hl=3

Edwin was referring the original poster, not your issue. Changing the auxilary heater valve will not make a difference in your coolant circulation. What I said was an easy way to check the proper functioning of the water pump is to unplug the auxilary pump, if you still get hot air inside the cabin, then the main water pump is doing its job and you can rule that out as being the issue.

Here's a DIY showing you the placement on V8, should be the same as the V12. In the second pic you can see the connector that you unplug

http://www.bimmerboard.com/forums/posts/59836/

[RIboater]

On the V12 the valves/pump is by the side of the engine next to the shock tower. A little easier to access. believe it or not....
There are two electric connections on these. One for the valves and one for the circulation pump. The only connector visible in that second pic is for the valves, not the pump.
Didn't have much time to deal with this problem this weekend but it's warm in the car when it's 32f/0c out so I don't care. Let the lower hose be cold. Engine temp is right at 108-110c like it's supposed to be.

[e30luv318i]

Edwin was referring the original poster, not your issue. Changing the auxilary heater valve will not make a difference in your coolant circulation. What I said was an easy way to check the proper functioning of the water pump is to unplug the auxilary pump, if you still get hot air inside the cabin, then the main water pump is doing its job and you can rule that out as being the issue.

Here's a DIY showing you the placement on V8, should be the same as the V12. In the second pic you can see the connector that you unplug

http://www.bimmerboard.com/forums/posts/59836/

what if you unplug it and its still the same? like still cold

[RIboater]

should have kept my mouth shut. just now after just a 20 min. ride i saw the temp hit 111c. no big deal right? when i got out of the car i could hear the steam. opened the hood and i was overheating. the gauge on the dash was fine and no lights came on.
i'm really hating this car right now.

[darkstarmedia]

should have kept my mouth shut. just now after just a 20 min. ride i saw the temp hit 111c. no big deal right? when i got out of the car i could hear the steam. opened the hood and i was overheating. the gauge on the dash was fine and no lights came on.
i'm really hating this car right now.

You might want to start a new thread... to issues in one thread can get confusing....

richard

[mikasaur]

n00b here with similar problem. Heat seems to come out of the floor vents, but I have cold air coming out of the dash and defroster vents. A/C seems fine and temp gauge on dash is fine.

Now for the stupid question: where are the heater/water valves? Is that something under the hood or behind the dash? Do I have to take apart my interior?

Thanks.

[novasol]

n00b here with similar problem. Heat seems to come out of the floor vents, but I have cold air coming out of the dash and defroster vents. A/C seems fine and temp gauge on dash is fine.

Now for the stupid question: where are the heater/water valves? Is that something under the hood or behind the dash? Do I have to take apart my interior?

Thanks.

For what an E38 or the M3?

[Her740]

Just an update as I like to do when I fix something! I ordered a new heater valve w/secondary waterpump from KO Performance, for $340, cheapest new one I could find. Free shipping, I paid $5 for 3 day shipping. Arrived in 3 days, packed well. Took all of about 30-40 minutes to change it over and now it's so fricken' hot, I couldn't turn the heat down far enough!!

Mikasaur: If you have an E38, the heater control valve is on the firewall, basically right in front of the driver. It is directly behind the left valve cover, it looks like two round cylinders on top. There are three heater hoses to disconnect. Two on top, directly across from each other and one on the bottom right (passenger side.) There are also two plugs, one right on the top right and one on the lower right. I also disconnected the brake booster hose to gain a little more room. The assembly just lifts straight up. New one goes in just as easy. Reconnect everything and your good. I only disconnected the heater hoses from the valve and moved them out of the way. I did not remove completely. If I had to guess, I only lost about a cup of coolant doing this and if more, not much more. I did do the obligatory cooling system bleed afterwards as well and will keep my eye on it for the next few days because, I didn't end up adding any coolant. Again, super easy about 30-40 minutes only used a 1/4 inch ratchet with about a 6 inch extension and a swivel socket, (sorry, forget what size...small) for the hose clamp. I also used a screw driver to help pull the hoses back off the old valve. I can post pictures if anybody would like, later.

Sean

[darkstarmedia]

Just an update as I like to do when I fix something! I ordered a new heater valve w/secondary waterpump from KO Performance, for $340, cheapest new one I could find. Free shipping, I paid $5 for 3 day shipping. Arrived in 3 days, packed well. Took all of about 30-40 minutes to change it over and now it's so fricken' hot, I couldn't turn the heat down far enough!!

Mikasaur: If you have an E38, the heater control valve is on the firewall, basically right in front of the driver. It is directly behind the left valve cover, it looks like two round cylinders on top. There are three heater hoses to disconnect. Two on top, directly across from each other and one on the bottom right (passenger side.) There are also two plugs, one right on the top right and one on the lower right. I also disconnected the brake booster hose to gain a little more room. The assembly just lifts straight up. New one goes in just as easy. Reconnect everything and your good. I only disconnected the heater hoses from the valve and moved them out of the way. I did not remove completely. If I had to guess, I only lost about a cup of coolant doing this and if more, not much more. I did do the obligatory cooling system bleed afterwards as well and will keep my eye on it for the next few days because, I didn't end up adding any coolant. Again, super easy about 30-40 minutes only used a 1/4 inch ratchet with about a 6 inch extension and a swivel socket, (sorry, forget what size...small) for the hose clamp. I also used a screw driver to help pull the hoses back off the old valve. I can post pictures if anybody would like, later.

Sean

Just so you know on 750's the heater control valve unit is on the shock tower...

richard