Coolant on floor after Thermostat replacement

jumpman86 · 10-12-2019, 10:10 PM

Hi All,

Apologize in advance for the long read but appreciate any incites in advance.

I attempted my first DIY on my 08 e90 M3 today and I swapped out the thermostat, temp senor and also the Fuel Tank Breather part.

As for the Thermostat swap, I took out as much fluid from the overflow tank reservoir as possible, but unfortunately, i did spill quite a bit of coolant when removing the hoses attached to the thermostat housing. I cleaned up as much as I could see and reinstalled everything once the new thermostat is on. I also replaced the 4 o-rings that are at the back of the housing unit.

Everything seems to work after bleeding the coolant a bit. I saw that some coolant came off the car as I backed out of the driveway. I think they were from the spillage during the swap.

I took a short 15 min drive and everything seems to be good. I parked the car in the garage and put a cardboard on the floor and 3 hours later, i see a small puddle of coolant on the cardboard.

I then removed the plenum (much faster this time) and checked if there were any leaks. From what I can see up top, there were no leaks from the housing nor the coolant pipes.

Do you guys think the coolant that were spilled during the swap can take some time to completely drip from the bottom of the car.

Anyone has any experience on this swap? I initially though the back of the housing where the 4 o rings were replaced were leaking but I dont see any leaks there as well.

Took me 5 hours total and would hate to redo everything again as my back is aching now as I type

Thanks in advance.

Ed

msan · 10-12-2019, 11:42 PM

From what I've read usually the leak, if there truly is a leak, will occur where those 4 o-rings are. Did you lubricate the orings with some coolant when putting them back together so they don't snag and tear?

Good luck! Hope its just spilled coolant dripping out

pbonsalb · 10-13-2019, 06:26 AM

It takes some force to full seat the housing, so maybe it is not all the way on. And as noted, you could damage an o-ring when installing, particularly if you did not lubricate them. I think there is a small hose that attaches as well, so make sure it is fully seated.

At this point, it’s probably not just left over spilled coolant, but you will know in a day or so.

jumpman86 · 10-13-2019, 07:00 AM

Thanks all.

I ran your posts on the other DIY thermostat thread as well. Thanks for your helpful contribution to that thread.

I checked the o-rings for leak and seems dry right now.

While i have t plenum off, I am going to start the car without it today and see if there are any leaks from the o-rings area.

My observation is that most coolant (probably less than half a cup came down on the cardboard from the 1st 3 hours. Since then, only a few drips were on the new cardboard 10 hours ago. The rate of drip definitely slowed and maybe stopped but I wont know until i run the car a bit.

Another question for you, do i have to wash out all the coolant that got on other parts of the engine or do I just wipe it dry? Thanks all.

jumpman86 · 10-13-2019, 06:45 PM

I think I found out the leak, it's from the hose from the expansion tank to the thermostat housing. I saw coolant dripping from that spot when car is running.

Part number 11537838219. Hope this solves the problem.

Other wise, I have no clue what else can be leaking. Thanks.

Thanks all.

ItsGary · 10-13-2019, 07:07 PM

I spilled a lot of coolant when I did the job. A lot of the coolant ends up resting in the skid plate until you move the car around, once it gets a little bit of a drip going its going to continue until the levels are low or gone. Hopefully its just a pipe, I did replace all 4 o-rings myself too

SAMM3Y · 10-13-2019, 07:13 PM

Quote:

Originally Posted by jumpman86

I think I found out the leak, it's from the hose from the expansion tank to the thermostat housing. I saw coolant dripping from that spot when car is running.

Part number 11537838219. Hope this solves the problem.

Other wise, I have no clue what else can be leaking. Thanks.

Thanks all.

The end of the hose gets brittle and breaks off inside the housing. When you remove it, find a lag bolt/screw just the right size to thread into the broken piece and pull it out with a pair of pliers.

jumpman86 · 10-13-2019, 07:29 PM

Thanks Samm3y, I think there may be a small broken piece inside. Will try your method.

Itsgary, I hope most of that is coming from the skid plate along with the small leak from the expansion pipe.

SAMM3Y · 10-13-2019, 08:20 PM

Quote:

Originally Posted by jumpman86

Thanks Samm3y, I think there may be a small broken piece inside. Will try your method.

Itsgary, I hope most of that is coming from the skid plate along with the small leak from the expansion pipe.

It snaps off after the oring and the coolant goes through the hollow tube and up thru the crack, so you get a slow but steady drip. So when you pull the broken piece out it comes with the oring, so have a good purchase when you pull.

You know it's broken if you can spin the hose freely.

jumpman86 · 10-13-2019, 08:26 PM

Samm3y, when you say, have a good purchase when I pull, are you saying that I should buy the oring too? Thanks.

SAMM3Y · 10-13-2019, 08:44 PM

Quote:

Originally Posted by jumpman86

Samm3y, when you say, have a good purchase when I pull, are you saying that I should buy the oring too? Thanks.

No I mean have a good grip cuz it takes a good pull to get the old one out cuz the oring is still in there. It takes a little leverage, make sure the screw has a hold of it.

jumpman86 · 10-13-2019, 09:24 PM

Got it, thanks so much for your advice. I do still see the oring in the housing unit and I was able to pull it out to check if it still good.

10-12-2019, 10:10 PM	#1
jumpman86 First Lieutenant 26 Rep 306 Posts Drives: bmw M3 Join Date: Dec 2008 Location: anywhere iTrader: (3)	Coolant on floor after Thermostat replacement Hi All, Apologize in advance for the long read but appreciate any incites in advance. I attempted my first DIY on my 08 e90 M3 today and I swapped out the thermostat, temp senor and also the Fuel Tank Breather part. As for the Thermostat swap, I took out as much fluid from the overflow tank reservoir as possible, but unfortunately, i did spill quite a bit of coolant when removing the hoses attached to the thermostat housing. I cleaned up as much as I could see and reinstalled everything once the new thermostat is on. I also replaced the 4 o-rings that are at the back of the housing unit. Everything seems to work after bleeding the coolant a bit. I saw that some coolant came off the car as I backed out of the driveway. I think they were from the spillage during the swap. I took a short 15 min drive and everything seems to be good. I parked the car in the garage and put a cardboard on the floor and 3 hours later, i see a small puddle of coolant on the cardboard. I then removed the plenum (much faster this time) and checked if there were any leaks. From what I can see up top, there were no leaks from the housing nor the coolant pipes. Do you guys think the coolant that were spilled during the swap can take some time to completely drip from the bottom of the car. Anyone has any experience on this swap? I initially though the back of the housing where the 4 o rings were replaced were leaking but I dont see any leaks there as well. Took me 5 hours total and would hate to redo everything again as my back is aching now as I type Thanks in advance. Ed
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10-12-2019, 11:42 PM	#2
msan Major 403 Rep 1,171 Posts Drives: 2011 E90 M3 / 2012 X5 35i M Sp Join Date: May 2015 Location: Los Angeles, CA iTrader: (16)	From what I've read usually the leak, if there truly is a leak, will occur where those 4 o-rings are. Did you lubricate the orings with some coolant when putting them back together so they don't snag and tear? Good luck! Hope its just spilled coolant dripping out
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10-13-2019, 06:26 AM	#3
pbonsalb Lieutenant General 5212 Rep 10,594 Posts Drives: 18 F90 M5, 99 E36 M3 Turbo Join Date: Feb 2011 Location: New England iTrader: (4)	It takes some force to full seat the housing, so maybe it is not all the way on. And as noted, you could damage an o-ring when installing, particularly if you did not lubricate them. I think there is a small hose that attaches as well, so make sure it is fully seated. At this point, it’s probably not just left over spilled coolant, but you will know in a day or so.
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10-13-2019, 07:00 AM	#4
jumpman86 First Lieutenant 26 Rep 306 Posts Drives: bmw M3 Join Date: Dec 2008 Location: anywhere iTrader: (3)	Thanks all. I ran your posts on the other DIY thermostat thread as well. Thanks for your helpful contribution to that thread. I checked the o-rings for leak and seems dry right now. While i have t plenum off, I am going to start the car without it today and see if there are any leaks from the o-rings area. My observation is that most coolant (probably less than half a cup came down on the cardboard from the 1st 3 hours. Since then, only a few drips were on the new cardboard 10 hours ago. The rate of drip definitely slowed and maybe stopped but I wont know until i run the car a bit. Another question for you, do i have to wash out all the coolant that got on other parts of the engine or do I just wipe it dry? Thanks all.
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10-13-2019, 06:45 PM	#5
jumpman86 First Lieutenant 26 Rep 306 Posts Drives: bmw M3 Join Date: Dec 2008 Location: anywhere iTrader: (3)	I think I found out the leak, it's from the hose from the expansion tank to the thermostat housing. I saw coolant dripping from that spot when car is running. Part number 11537838219. Hope this solves the problem. Other wise, I have no clue what else can be leaking. Thanks. Thanks all.
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10-13-2019, 07:07 PM	#6
ItsGary Colonel 1458 Rep 2,336 Posts Drives: 2009 E90 M3 Join Date: Oct 2017 Location: Vancouver iTrader: (0)	I spilled a lot of coolant when I did the job. A lot of the coolant ends up resting in the skid plate until you move the car around, once it gets a little bit of a drip going its going to continue until the levels are low or gone. Hopefully its just a pipe, I did replace all 4 o-rings myself too __________________ '09 ///M3 Sedan - Jerez Black/Fox Red Ext. '09 335i Coupe - Alpine White/Black - SOLD
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10-13-2019, 07:29 PM	#8
jumpman86 First Lieutenant 26 Rep 306 Posts Drives: bmw M3 Join Date: Dec 2008 Location: anywhere iTrader: (3)	Thanks Samm3y, I think there may be a small broken piece inside. Will try your method. Itsgary, I hope most of that is coming from the skid plate along with the small leak from the expansion pipe.
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10-13-2019, 08:26 PM	#10
jumpman86 First Lieutenant 26 Rep 306 Posts Drives: bmw M3 Join Date: Dec 2008 Location: anywhere iTrader: (3)	Samm3y, when you say, have a good purchase when I pull, are you saying that I should buy the oring too? Thanks.
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10-13-2019, 09:24 PM	#12
jumpman86 First Lieutenant 26 Rep 306 Posts Drives: bmw M3 Join Date: Dec 2008 Location: anywhere iTrader: (3)	Got it, thanks so much for your advice. I do still see the oring in the housing unit and I was able to pull it out to check if it still good.
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