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Old 01-05-2017, 06:31 PM   #1
cscracker
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Heat problems

Hi everyone, I have a frustrating issue with my heat that I'm running out of ideas on and need some help.

I have a 1989 325iX that I got in fairly rough shape and I've been fixing up. I put a new (rebuilt) head on the engine and replaced just about every wear item that comes out when you do that, including all of the cooling system. I'm having issues with the heat - it gets warm, but never hot, and it's warmer when the car's sitting still than when it's moving. The faster you go, the colder it is. The engine also doesn't get as warm as I expected it to, it goes to at or just below the first white dash, and doesn't move much from there. My last e30 would always sit just above that dash, and this one did too before I tore it apart.

I've replaced pretty much every part of the cooling system except the heater core and the metal pipes coming through the firewall - all new rubber hoses, new cxracing aluminum radiator, new thermostat housing and thermostat and sensors, new coolant expansion tank, new water pump. I drained all the coolant out, radiator and block plug. I filled the cooling system with BMW coolant in a 67/33 mix with some water wetter (I live in a climate that gets well below 0 degrees), and I used an evacuation tool to pull vacuum on the system before filling. I've bled it both level and parked up a hill, and I'm 99.9% sure there is no air in the system. No air came out during any of my bleeding attempts, which makes sense if my evacuation tool worked properly.

I deleted the secondary thermostat - due to part availability more than anything else, but also to simplify it. I know I have the hoses on correctly because I didn't at first and had to redo it - top hose to the thermostat housing, bottom hose to the port on the back of the head.

Aside from the heater core possibly being plugged up and needing replacement, I have one other idea. I had the car parked and the heat on, and put my hand up under the dash, and found that there were two streams of air blowing around in there, one cold and one hot. If the car is leaking cold air in somewhere from the atmosphere and mixing it with the hot air, that could explain it, but I don't know enough about it to know where or how it could be doing this. The heater core itself is very hot to the touch, as it should be.

My car is equipped with air conditioning, but I removed the belt from the compressor because it doesn't work and was making awful noises. My blower motor probably needs replaced as it makes a lot of noise and seems like the bearings might be shot, but it does move a fair amount of air and I should still be able to get hot heat. I am also currently running without a radiator fan. The fan clutch is bad and the fan tore a hole into one of my radiator hoses, so I removed it when I replaced that hose.

Thanks for any help you can offer.

I have some pictures if you're interested in the progress, though they were taken before I got the new radiator and the hoses on straight:
http://pics.deadface.org/phone/e30/
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Old 01-05-2017, 08:14 PM   #2
M_3_X
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Did you remove the coolant hoses to and from the heater core through the firewall? I've read that is possible to mix the up during re installation making the heater behave erratically.
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Old 01-05-2017, 10:02 PM   #3
long tall eta
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the car is warm when not moving and cold when moving due to you not having a radiator fan. when the car is in motion, the air flow is cooling down the coolant and while standing still. the lack of air flow lets it increase in temp. also if you have the wrong thermostat or a non operating thermostat, it won't open and close correctly or maybe not at all allowing the coolant to flow freely through the motor resulting in the car never reaching operating temps.
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Old 01-06-2017, 04:59 AM   #4
ahlem
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There is an electrical valve on the pipes that connect into the heater core that can go bad.
It's right above your gas pedal. If that doesn't open you wont get any heat. The wires may have fallen off.
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Old 01-06-2017, 05:05 AM   #5
vpilarrt
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Are you sure the heater control valve is opening when you turn the control to hot?
Turning the control to hot should also close a flap in the heater box that directs the outside air thru the heater core. Is that working? Are the foam seals around the flap bad?
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Old 01-06-2017, 06:51 AM   #6
cscracker
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I know the heater hoses are on correctly, because I had them wrong when I first put it together and had to fix it.

The thermostat is brand new but it's possible they sent me the wrong one or it's defective. It doesn't appear to be stuck all the way open because the engine does warm up to about that first dash at the same rate no matter the weather and stays close to that spot. Is there a way to know without draining the coolant? I have a FLIR handheld camera so I can see and record the temperature of different parts as it warms up.

I think you're on to something with the flapper at the heater valve. I think the valve is working but the flapper may not be, or the seal may be bad. Do I need to remove the center console to see it?

Thanks again for all the suggestions.
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Old 01-06-2017, 07:05 AM   #7
Kershaw
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The thermostat should open at 80C/176F. Can you verify that your coolant is running at that temp?
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Old 01-06-2017, 07:18 AM   #8
superj
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yes, you have to pull the lower console to get to that valve. its easy though, pull the shifter stuff and undo some screws above the coin holder and some plastic push plugs by your feet on each side and it just lifts up. then the heater valve is easily accessible above your gas pedal. and the heater core can also easily be pulled and cleaned since it is right there. its very easy to pull, you will see.
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Old 01-07-2017, 10:30 PM   #9
cscracker
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Ok, I tested it with my FLIR, and I'm sure the thermostat is working correctly. The hose from the thermostat toward the lower radiator housing stays cold until the other side of the housing its about 80C +/- ~3C. I also verified the heater hoses are both hot once it starts to warm up, so hot water is getting in and back out. The inlet hose is about 70-75C and the outlet hose is about 55-65C.

I removed the center console and as much stuff as I could to try and see what's going on in there. I'm really not sure what to check in terms of wiring and I still don't see the flapper, but as you'll see in this picture, the wiring is a disaster on this car (previous owners' handiwork). I was going to take more pictures but my phone died when I tried to take the next one.


Last edited by cscracker; 01-07-2017 at 10:46 PM. Reason: Spacing
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Old 01-07-2017, 11:38 PM   #10
uturn
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I spy... the old heater core inlet valve(that light blue thing). I also see green tinge from a small leak forming as well as carpet staining. Touch it as you turn the temp dial and feel if it clicks. It could be clogged inside. New from BMW is a new design and spendy if in stock.
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Old 01-08-2017, 06:41 AM   #11
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Yup, top right of the pic under the green box
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Old 01-08-2017, 08:29 AM   #12
cscracker
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Thanks. I'll get a closer look at it today.

Is this one the new design? It looks similar to the one I have now.
https://www.ecstuning.com/b-genuine-...e/64111386706/

Or is it this one, that says it's for aluminum inlets, here?
https://www.ecstuning.com/b-genuine-...e/64111386707/

And if it is the second one, do I need to replace the plastic inlets to use it?
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Old 01-08-2017, 09:12 AM   #13
superj
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Second one. Which plastic inlets
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Old 01-08-2017, 02:17 PM   #14
vpilarrt
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I looks like you have to remove either the heater core or the AC evaporator to be able to see the flap I was talking about. On my car when you turn the heat control to full cold you can hear the flap open (or close, whichever one it might be) with a slight thump.
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Old 01-29-2017, 09:20 PM   #15
cscracker
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Replaced the valve and heater core, as well as the blower motor (bearings were toast), and now it's quiet, and the heat is considerably warmer. I also got the recirculation flaps unstuck while I was in there, and replaced/fixed a bunch of broken stuff in my center console. I don't have everything back in yet so I only took a short test ride, but it's already a lot better.

I also found a fairly large hole in the firewall that was missing a plug, I think it's a 35mm, which was definitely not helping. I ran some wires through it for my wideband and I'm ordering some plugs to see what fits. Couldn't find the original part, but found some that ought to work.

Unrelated, I finally fixed my misfire (bad or wrong fuel injector on #5) and now it runs great. Frustrated that one of my expensive refurbished Bosch design IIIs was DoA, but very happy that the car runs right again, better than ever. I'll probably just keep the old one in there until I go for turbo and get bigger ones.

Thanks for all the help.
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