E46 Fanatics Forum banner
1 - 18 of 18 Posts

·
Registered
2000 328i Sport, 2003 325iT
Joined
·
34 Posts
Discussion Starter · #1 ·
I recently purchased my second E46 in the fall of 2020. One of the first things I took care of was bleeding the cooling system since I was getting an intermittent coolant light and little to no heat (I believe this gave me heat again for a short period of time). The previous owner had stated that he refreshed the cooling system the previous year, however when I noticed coolant began spraying all over the front of the engine, car overheating, coolant smelling steam/ smoke, and slow leak on the ground, I ended up refreshing it again. Here is what I replaced:

Mahle Expansion Tank
Mahle Thermostat
Graf Water Pump
OEM Coolant Temp sensor & gasket
Hudson (OE brand?) upper and lower hoses

After bleeding the system and letting the car get to operating temp, I noticed lots of steam/smoke coming from the radiator. At first I assumed that some of the coolant may have spilled on it and it was burning it off. After a few days this smoke has seemed to go away significantly, but I check and notice it from time to time after I get out of the car. I am considering replacing this just to rule it out, but I'm holding out until I get some feedback on my situation.

I still have no heat. I do believe I bled the system correctly as I also did the exact same procedure on my 2000 328i with no issues. The hoses are warm/hot after driving.

I did some research on here and was curious to see that some people remedied this problem with a new Final Stage Resistor? I do have one on order since my vents don't really blow any air at anything but the two highest settings, but I don't want to get my hopes up that that will be the fix.

Any help is appreciated. I still have a lot to learn about these cars and I hope this isn't too much info. First post!
 

·
Registered
Joined
·
9,090 Posts
I still have no heat. I do believe I bled the system correctly as I also did the exact same procedure on my 2000 328i with no issues. The hoses are warm/hot after driving.
Use the hidden display and see what coolant temp at operating condition. Is the low radiator hot?
Unplug the heater valve cable and this forces the valve to open, then see if the valve body gets hot as coolant passing through.
 

·
Registered
2000 328i Sport, 2003 325iT
Joined
·
34 Posts
Discussion Starter · #5 ·
Use the hidden display and see what coolant temp at operating condition. Is the low radiator hot?
Unplug the heater valve cable and this forces the valve to open, then see if the valve body gets hot as coolant passing through.
Operating temp is 95. I've been watching it a lot. Where is the heater valve cable located?
 

·
Registered
2000 328i Sport, 2003 325iT
Joined
·
34 Posts
Discussion Starter · #7 ·
Driver side under the air intake, along the frame rail.

Sent from my ONEPLUS A6000 using Tapatalk
Im going to give this a shot in the morning. If I feel the valve body getting warm with coolant, will that tell me that the valve is stuck closed and that I need a new heater valve? Can I just leave it disconnected to have heat in my car?
 

·
Registered
Joined
·
9,090 Posts
Im going to give this a shot in the morning. If I feel the valve body getting warm with coolant, will that tell me that the valve is stuck closed and that I need a new heater valve? Can I just leave it disconnected to have heat in my car?
If the valve is warm with cable disconnected, which means hot coolant flows through it. If not then it's closed or no warm coolant.
 

·
Registered
Joined
·
2,424 Posts
Im going to give this a shot in the morning. If I feel the valve body getting warm with coolant, will that tell me that the valve is stuck closed and that I need a new heater valve? Can I just leave it disconnected to have heat in my car?
Feel the hoses coming in and out of it.

Sent from my ONEPLUS A6000 using Tapatalk
 

·
Registered
2000 328i Sport, 2003 325iT
Joined
·
34 Posts
Discussion Starter · #11 ·
Yes, default is open anyway. I'm surprised you were able to bleed it if the valve was closed while the engine was running.
oh is that what is supposed to be opening when you bleed the car with the heat on max temp? That makes sense. Didn't have any trouble bleeding the system to my knowledge.
 

·
Super Moderator
Joined
·
2,396 Posts
I am a little surprised you threw all those cooling system parts at it before you actually identified where the leak came from. You may have a leak in your radiator or something else you did not replace.

I just went through this yesterday on my e39.. I had a persistent leak, but only under pressure. I put 20 psi (no more) of air pressure to my cold cooling system and voila, I found a leak in the radiator...where plastic meets the aluminum. If you don't have a compressor, you can borrow a coolant pressure tester from autozone or other auto parts chain for free. It screws into the expansion tank.
 

·
Registered
2000 328i Sport, 2003 325iT
Joined
·
34 Posts
Discussion Starter · #13 ·
I am a little surprised you threw all those cooling system parts at it before you actually identified where the leak came from. You may have a leak in your radiator or something else you did not replace.

I just went through this yesterday on my e39.. I had a persistent leak, but only under pressure. I put 20 psi (no more) of air pressure to my cold cooling system and voila, I found a leak in the radiator...where plastic meets the aluminum. If you don't have a compressor, you can borrow a coolant pressure tester from autozone or other auto parts chain for free. It screws into the expansion tank.
I should probably look into that, thanks. The reason I replaced everything else was because the T-stat was bad, both upper hoses were leaking, the O-ring for the temp sensor was leaking, and I was hearing a hissing noise from the expansion tank area.
 

·
Registered
2000 328i Sport, 2003 325iT
Joined
·
34 Posts
Discussion Starter · #14 ·
I unplugged the heater valve and turned on the heat with the car at operating temp. Ran it for about a minute, still no real heat. Hoses going to the valve are warm, the valve itself was not.
 

·
Premium Member
2005 330xi Auto, 2006 330ci Vert Auto
Joined
·
1,285 Posts
I had the same symptoms as you. Even though the valve is designed to fail open, in my case it did not fail open. I replaced it with one I purchased from Amazon (Prime shipping as I wanted it fast and not pay outrageous shipping), bled the system again, and now I have heat.
 

·
Registered
Joined
·
9,090 Posts
I unplugged the heater valve and turned on the heat with the car at operating temp. Ran it for about a minute, still no real heat.
1) ran cold engine for a minute is too short to check heat.
2) If temp got to 95C and still having a cold valve, check and feel how hot is the radiator lower hose which tells us if you have coolant flow issue or not.
3) if lower hose is hot, then remove the valve hoses and check if it clogged or closed. It should be opened.
 

·
Registered
2000 328i Sport, 2003 325iT
Joined
·
34 Posts
Discussion Starter · #17 ·
1) ran cold engine for a minute is too short to check heat.
2) If temp got to 95C and still having a cold valve, check and feel how hot is the radiator lower hose which tells us if you have coolant flow issue or not.
3) if lower hose is hot, then remove the valve hoses and check if it clogged or closed. It should be opened.
I ran the engine for a minute at operating temperature, not cold. I’ll remove the valve hoses to check if they’re clogged or the valve is clogged or both?
 
1 - 18 of 18 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top