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:
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:
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