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Discussion Starter · #1 ·
Ok, two weeks ago, I did the cooling overhaul, water-pump, thermostat, expansion tank, upper and lower radiator hoses. Hose popped off the expansion tank so I filled it with water after I got the hose back on, and went on my way. Different hose popped off again a few nights ago, so I put it back on and filled it with water, and this is when everything awful starts happening. After filling the car with water, I got back on the highway to the car overheating. Cut the car off and pulled off immediately. Had to stop three more times on the way home to let it cool off before trying again. This morning I picked up coolant and distilled water and tried to flush the cooling system. The bolt on the block was impossible to get off, so I left it but was able to flush everything else. The whole time the key was in the on position and the heater was on low and 91 degrees. After the flush, I started the car and ran it until it came to temp and dropped it off the jack stands... Took it for a ride around the block and the temperature climbed again. On the OBC it started on 101 and got to 115 before coasting back into the driveway. I don't know why its dong this, should I flush the coolant again or could it be another problem? Now the whole time, once the car REACHES temp, hot air blows out, but until then, nothing really comes out. Also, when draining the coolant today, there was no oil so I hope its not a head gasket.
 

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1. Verify that the pump is spinning (I know this is trivial, but worth mentioning... I've seen wrong belt routing before)
2. Thermostat possibly went south, even though it's new.
3. Air in the system - most likely case here. Search for proper bleeding procedures.
 

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Bleeding is different from flushing the system.
Flushing the system to replace the whole fluid is useful occasionaly, but you probably have air bubbles in the system. Bubbles, more like air pockets, will stop the water from circulating properly. There's a million threads that help you learn how to Bleed the system of air.
Basically,
1) run the car - heater on is helpful, but not critical in my experience
2) unscrew the bleeder screw at the top of the radiator next to the cap and have the cap off the radiator
3) fill to the top
4) squeeze the hell out of the hoses (upper rad hose is easily accessable) - this forces the water through the system faster
5) watch the level of coolant/water mix and refill as needed
6) repeat squeezing and refilling
6) wait for coolant to come out of the bleeder screw instead of air
7) button her back up - cap and bleeder screw - you're all done.

8) keep some extra pre-mixed coolant/water in a bottle in the car for a week or so. Refill if you notice the level drop. There may be more bubbles.

Other possibility is faulty thermostat. It can happen.
 

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^after you did all he said let the car sit over night. Turn the key over but do not start the car. Set the temp on low and unscrew the bleed screw. There will still be air in the lines and that's the best way you will get all of the air pressure out. (after you have drove/warmed the car up previous day)
 

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Discussion Starter · #6 ·
Thanks for your help guys! I've done a little searching and couldn't find the answer, but what the highest my OBC should read when idling?
 

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Thanks for your help guys! I've done a little searching and couldn't find the answer, but what the highest my OBC should read when idling?
there has been some debate on this, somewhere between 90-100c depending. I believe our spec is 97c, however mine wont get above 90 since I changed out my thermostat. YMMV
 

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@auto180sx

Your readout should be at ~ 97C once your motor is warmed up / idling.

Also, Proper Bleeding can take 30 minutes or More to evacuate all the air from a major cooling system Refresh like the one you've done. And, when several Hose(s!) are popping off like that after the install... I dear say you rushed your DIY - you didn't double check your work. So, follow the instructions mentioned above carefully. DO NOT rush this process.

Regarding possible head gasket damage... when you were driving home from the overheat, did the red light come on in the temperature gauge? If so, how long did you drive with that light on after the fact??
 

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Bleeding is different from flushing the system.
Flushing the system to replace the whole fluid is useful occasionaly, but you probably have air bubbles in the system. Bubbles, more like air pockets, will stop the water from circulating properly. There's a million threads that help you learn how to Bleed the system of air.
Basically,
1) run the car - heater on is helpful, but not critical in my experience
2) unscrew the bleeder screw at the top of the radiator next to the cap and have the cap off the radiator
3) fill to the top
4) squeeze the hell out of the hoses (upper rad hose is easily accessable) - this forces the water through the system faster
5) watch the level of coolant/water mix and refill as needed
6) repeat squeezing and refilling
6) wait for coolant to come out of the bleeder screw instead of air
7) button her back up - cap and bleeder screw - you're all done.

8) keep some extra pre-mixed coolant/water in a bottle in the car for a week or so. Refill if you notice the level drop. There may be more bubbles.

Other possibility is faulty thermostat. It can happen.
OP, this might work, but many subscribe here to the bleed the way bmw TIS says...which is engine off, but key to Pos 2

Heater on highest temp, 3 red dots in center vent, fan on low

slowly add coolant until it comes out open bleeder screw bubble free.

Then, close it up, get to op temp, let it cool down and add coolant in a.m. as necessary.

Many here don't have good results doing that, probably coz they pour coolant in too fast...and thus bmw has added two, I believe, 30 secs. of running the car during the bleeding procedure.

I'm sure it's with bleeder closed and cap on, but I'm not sure about that...I haven't seen the new TIS but once, but I know it's here somewhere.
 

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Discussion Starter · #11 ·
@auto180sx

Your readout should be at ~ 97C once your motor is warmed up / idling.

Also, Proper Bleeding can take 30 minutes or More to evacuate all the air from a major cooling system Refresh like the one you've done. And, when several Hose(s!) are popping off like that after the install... I dear say you rushed your DIY - you didn't double check your work. So, follow the instructions mentioned above carefully. DO NOT rush this process.

Regarding possible head gasket damage... when you were driving home from the overheat, did the red light come on in the temperature gauge? If so, how long did you drive with that light on after the fact??

I know, and I learned from my mistakes so I wont be rushing things like that any more. As for the car overheating, the car was only "in the red" for a split second, as the car was turned off.

Thank you everyone for your help today! I bled the system today, so hopefully all is well now.
 

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OP, this might work, but many subscribe here to the bleed the way bmw TIS says...which is engine off, but key to Pos 2

Heater on highest temp, 3 red dots in center vent, fan on low

slowly add coolant until it comes out open bleeder screw bubble free.

Then, close it up, get to op temp, let it cool down and add coolant in a.m. as necessary.

Many here don't have good results doing that, probably coz they pour coolant in too fast...
This method worked for me, the key is to slowly pour in the coolant. I mixed my coolant/distilled water as I went, one bottle at a time, leaving plenty of time for the coolant to settle and the air to escape.
 

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Discussion Starter · #13 ·
Ok guys, how do I tell if a thermostat is dead? The car has shot out sooo much coolant and air that I still don't know how there is any in there! I've bled the car 5 different ways and I just feel like 'm going nuts and nothing is going to fix it.... I am losing hope. If your in the Columbia, SC area and have time to look at the car today, PM me PLEASE!
 

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You may need to have girlfriend/wife/whomever vid what you're doing.
Because with what you're verbally describing - what you have or haven't done is not giving us the actual account of what's happening.

if you had a Bad Main thermostat, you would* likely get some error codes.

>>>> I didn't ask, but do you have an automatic or manual? If you have an Auto, did you replace the transmission thermostat that is located inside the bottom socket mount of your Expansion Tank??? I didn't see it mentioned as a replacement part you did. If you didn't replace that, it could have been damaged or is FAILED, causing your cooling system to no circulate properly. Did you see my video talking about the topic?

NOTE: Bleeding the cooling system takes time, BUT is Not difficult to do especially with all the help/instructions given above by all the members.
The only thing I see missing from the instructs... is to (on occasion) raise the front of your vehicle by a couple of degrees to help "motivate" any stuck air-pockets to get out of the system easier.


* "may" - is more like it.
 

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Discussion Starter · #15 · (Edited)
No, the cars a manual.

To start out the day, I mixed my coolant and water, opened the bleeder screw and topped off the expansion tank. After that, I turned the car on, and let it idle while watching the OBC at which point the bleeder screw was closed and the car turned off once it reached 100c. Of course this was repeated a few times after letting the car sit for a bit..

Edit: The car blows out hot air when it should also, and it does get pretty hot...
 

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The thing that scares me the most is the thing you mentioned about hoses coming off and now that it's still shooting coolant. When I did my new therm, not a drop leaked from the new hoses and one bleed was enough (using the method I described). I'm not sure what you're doing and you certainly shouldn't be losing any coolant at this point if everything was installed correctly.
I fear that you may just need to bring it in to a shop.
 

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Discussion Starter · #17 ·
The thing that scares me the most is the thing you mentioned about hoses coming off and now that it's still shooting coolant. When I did my new therm, not a drop leaked from the new hoses and one bleed was enough (using the method I described). I'm not sure what you're doing and you certainly shouldn't be losing and coolant at this point if everything was installed correctly.
I fear that you may just need to bring it in to a shop.
I'm losing coolant through the bleeder screw.... NOT the hoses.
 

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I'm losing coolant through the bleeder screw.... NOT the hoses.
Did you lose the rubber o-ring on the bleed screw? There should be a rubber o-ring on the bleed screw. You might have over tightened the bleed screw and ruined the o-ring or not tightened it enough. Make sure everything is cooled down when you screw the bleed screw back down. (let the car sit for a few hours then tighten it back down)
 

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Discussion Starter · #19 ·
Did you lose the rubber o-ring on the bleed screw? There should be a rubber o-ring on the bleed screw. You might have over tightened the bleed screw and ruined the o-ring or not tightened it enough. Make sure everything is cooled down when you screw the bleed screw back down.
No, when I say I am loseing coolant through the bleeder screw, it because its open and I am tring to bleed the system. I also bought a new bleeder screw this morning from BMW along with MORE coolant...

I'm just so frustrated with everything so I know I sound pretty confusing right now. Thank you everyone for your help, its greatly appreciated, and hopefully my baby can get back on the road.. (Today hopefully...)
 

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I'm surprised to hear there are that much coolant coming out of your bleeder screw when you're bleeding. You realize you do Not have to completely remove the screw, just loosen it enough to allow air to escape.

Also, it should be screw down finger tight... no need to crank/torque that thing.
 
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