Coolant boiling in overflow tank
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Neutral
Joined: Jun 2017
Posts: 10
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Coolant boiling in overflow tank
Looking for your expert suggestion. I have R56. The coolant boiling in overflow tank just happened to me. Yesterday, after the drive home I smell the coolant when I parked. When I opened the hood, I see coolant boiling a little bit in the tank and coolant being pressurized out of vent (top) and bottom hoses of the tank.
First I thought those hoses caused the leak resulting the boiling, so I put a new hose tide for the top and reconnect the bottom hose. I test-drove again and when I came back it still did the same (boiling and pressurizing coolant out of top and bottom hoses.
I also just noticed that I could not hear the fan running even after I left the car running after the drive. It's dark and I didn't have a flash light to confirm if the fan's actually running and it was running so quietly that i couldn't hear anything. Or the fan didn't run at all. However, I could hear it running though when I turned on the A/C.
I checked coolant and it doesn't have any oil contaminated. I also checked oil and it checked out ok.
What would be the next thing you would recommend I should check?
Thank you very much for your help.
First I thought those hoses caused the leak resulting the boiling, so I put a new hose tide for the top and reconnect the bottom hose. I test-drove again and when I came back it still did the same (boiling and pressurizing coolant out of top and bottom hoses.
I also just noticed that I could not hear the fan running even after I left the car running after the drive. It's dark and I didn't have a flash light to confirm if the fan's actually running and it was running so quietly that i couldn't hear anything. Or the fan didn't run at all. However, I could hear it running though when I turned on the A/C.
I checked coolant and it doesn't have any oil contaminated. I also checked oil and it checked out ok.
What would be the next thing you would recommend I should check?
Thank you very much for your help.
Thread Starter
|
Neutral
Joined: Jun 2017
Posts: 10
Likes: 1
I will report back. Thank you.
Thread Starter
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Neutral
Joined: Jun 2017
Posts: 10
Likes: 1
After replacing the bottle and lower hose connector, I'm glad to say that I believe it fixed the boil-over issue. Test-drove for about 30 miles. Monitored the coolant temp using the hidden feature. It stayed between 102-105 C. Couple of things from this troubleshoot.
1. I noticed is that when I left the car idling, the fan will kick in when it reaches 108C then it will stop when the temp goes down around 103 or 104. I could not tell whether it's a low or high fan. I could hear kicking in and running, but I felt it's not that loud (supposedly it's a low fan, maybe). But I read it somewhere that the low fan should kick in around 105C and the high one would be around 110C. Mine doesn't sound normal.
2. When adding the coolant, I followed the bentley manual (Burping the system) but the coolant level didn't drop (rising instead) for me to add coolant as instructed. Then I tried the bleeding valve method (power on, highest heat, low fan). When adding coolant, nothing would come out from the bleeding valve. Weird! So, here is what I did.
- I decided to use the test tool to pressurize the system while leaving the bleeding valve open. I then saw coolant coming out from the valve.
- Filled up expansion tank and pressurized it again to make sure the coolant coming out without air (also making sure that there is still coolant in the tank).
- Closed the bleeding valve while coolant still coming out.
- filled up expansion tank to full
3. When installing the expansion tank, I found that the rubber grommet was missing. I didn't want to order a new one. I went to Lowe's and found a grommet ($1.5) that would fit. So, I used that instead of buying an OEM grommet. Hope this helps. See the pictures.
I'll continue to monitor the temp and coolant another week. If I don't come back to report, it means that it's fixed.
Thank you
1. I noticed is that when I left the car idling, the fan will kick in when it reaches 108C then it will stop when the temp goes down around 103 or 104. I could not tell whether it's a low or high fan. I could hear kicking in and running, but I felt it's not that loud (supposedly it's a low fan, maybe). But I read it somewhere that the low fan should kick in around 105C and the high one would be around 110C. Mine doesn't sound normal.
2. When adding the coolant, I followed the bentley manual (Burping the system) but the coolant level didn't drop (rising instead) for me to add coolant as instructed. Then I tried the bleeding valve method (power on, highest heat, low fan). When adding coolant, nothing would come out from the bleeding valve. Weird! So, here is what I did.
- I decided to use the test tool to pressurize the system while leaving the bleeding valve open. I then saw coolant coming out from the valve.
- Filled up expansion tank and pressurized it again to make sure the coolant coming out without air (also making sure that there is still coolant in the tank).
- Closed the bleeding valve while coolant still coming out.
- filled up expansion tank to full
3. When installing the expansion tank, I found that the rubber grommet was missing. I didn't want to order a new one. I went to Lowe's and found a grommet ($1.5) that would fit. So, I used that instead of buying an OEM grommet. Hope this helps. See the pictures.
I'll continue to monitor the temp and coolant another week. If I don't come back to report, it means that it's fixed.
Thank you
Neutral
Joined: Jan 2019
Posts: 1
Likes: 0
How much does the coolant expand in the overfill expansion tank when hot?
Hello,
I have a 2007 Mini Cooper 7. When cold, the coolant is within the low and high marks on the expansion tank, yet when running the car (coolant temp rises to 210 to 220 F) and turning it off, the coolant rises 2 inches above the high level mark, and sometimes appears to have bubbles within the tank. Is this normal, how much does hot coolant expand within the expansion tank in your Mini? I have done a coolant pressure test to look for leaks, and besides some minor seepage that is comes from the seams of the expansion tank (which I will soon replace), the pressure holds. I also ran three chemical tests to look for a blown head gasket and the Mini passed. The coolant temperature sensor was also recently replaced, and the water pump passed a test to ensure it was working.
So, how much expansion of the coolant is normal within Minis?
Thank you.
I have a 2007 Mini Cooper 7. When cold, the coolant is within the low and high marks on the expansion tank, yet when running the car (coolant temp rises to 210 to 220 F) and turning it off, the coolant rises 2 inches above the high level mark, and sometimes appears to have bubbles within the tank. Is this normal, how much does hot coolant expand within the expansion tank in your Mini? I have done a coolant pressure test to look for leaks, and besides some minor seepage that is comes from the seams of the expansion tank (which I will soon replace), the pressure holds. I also ran three chemical tests to look for a blown head gasket and the Mini passed. The coolant temperature sensor was also recently replaced, and the water pump passed a test to ensure it was working.
So, how much expansion of the coolant is normal within Minis?
Thank you.
