coolant weep?

[delirium330]

Has anyone else experienced a small coolant leak here? I think this is the vent hose for the thermostat back to the coolant expansion tank? Part #11537838219 (#12 in diagram)?

My coolant level has been fine so I assume this is just a weep or small leak. Not sure if there is a little gasket or something there in that vent hose that could be getting aged?

I wasn't sure if I changed out the hose if it would fix the problem or if anyone knows if the issue is actually the thermostat housing itself. And if I do change that hose, is coolant going to pour out or is this high enough as a sort of vent backstop and I can replace without making a mess?

[SAMM3Y]

Yes, the end of the hose is cracked off inside the water pump housing.. just happened to me the other day when I disturbed it installing an oil distribution block. I used a lag screw to get the stuck part out the pump housing..

And yes drain the coolant before you remove it or you'll have a quart maybe 2 of coolant on the floor..

[mapster37]

yes, pretty common leak on these cars. at least its easy to replace...

[delirium330]

Originally Posted by SAMM3Y

Yes, the end of the hose is cracked off inside the water pump housing.. just happened to me the other day when I disturbed it installing an oil distribution block. I used a lag screw to get the stuck part out the pump housing..

And yes drain the coolant before you remove it or you'll have a quart maybe 2 of coolant on the floor..

Would a radiator drain be sufficient to avoid a huge mess coming from that outlet? While I've overhauled the entire cooling system on my E46, I've never changed the coolant on my E92... had the shop do it when they did my rod bearings last year. Aren't the 2 engine block drain plugs virtually inaccessible?

[SAMM3Y]

Originally Posted by delirium330

Would a radiator drain be sufficient to avoid a huge mess coming from that outlet? While I've overhauled the entire cooling system on my E46, I've never changed the coolant on my E92... had the shop do it when they did my rod bearings last year. Aren't the 2 engine block drain plugs virtually inaccessible?

Yes radiator drain will be perfect 👌

[wfdeacon88]

I had this exact small coolant leak at this hose, I actually went in for an oil leak which ended up being the Oil filter housing. It was pretty cheap and easy fix for my Indy.

[Ajolives]

Originally Posted by SAMM3Y

Yes, the end of the hose is cracked off inside the water pump housing.. just happened to me the other day when I disturbed it installing an oil distribution block. I used a lag screw to get the stuck part out the pump housing..

And yes drain the coolant before you remove it or you'll have a quart maybe 2 of coolant on the floor..

Jack up the front of the car a little and maybe a pint will fall out.

[delirium330]

Originally Posted by Ajolives

Jack up the front of the car a little and maybe a pint will fall out.

Good thinking, going to give this a try over the weekend. I've got a steep driveway so might put it in the driveway... maybe on front wheel ramps as well as long as I don't bottom out the back. I really don't want to go through a full coolant drain just to change out this little hose...

[Ajolives]

Originally Posted by delirium330

Good thinking, going to give this a try over the weekend. I've got a steep driveway so might put it in the driveway... maybe on front wheel ramps as well as long as I don't bottom out the back. I really don't want to go through a full coolant drain just to change out this little hose...

I changed out the upper hose right next to it and not much came out at all with it tilted back. I also had plastic covering the engine down to the ground fed into a pan which also worked out well. I hate cleanup, haha.

[delirium330]

Originally Posted by Ajolives

I changed out the upper hose right next to it and not much came out at all with it tilted back. I also had plastic covering the engine down to the ground fed into a pan which also worked out well. I hate cleanup, haha.

I will be doing the same thing with a plastic sheet.

Did you do anything specific to bleed out the air after you installed the new hose? Coolant reservoir left open or bleed screw?

[Ajolives]

Originally Posted by delirium330

I will be doing the same thing with a plastic sheet.

Did you do anything specific to bleed out the air after you installed the new hose? Coolant reservoir left open or bleed screw?

I used the bleed screw until it snapped on me.

Bought a brass screw off amazon (fit for Mini Cooper but it's the same screw for us) and bled it again a couple times in 10 minute intervals, then once the next day to make sure no bubbles came out.

https://www.amazon.com/dp/B01N446111..._TNPvDb3ZB7FRV

[delirium330]

Yep, having owned other BMWs, replacing the plastic bleeder screw is one of the first things I do!

I got around to doing this repair today. When parking the car in the driveway I realized it wasn't as steep as I thought and was worried I didn't have it tipped back enough. I also couldn't get it on ramps or any higher than the slight pitch of the driveway.

Went pretty smooth overall. See below picture of what I rigged to capture the fluid that would leak out. Once I had the plastic Form A Funnel in place with the gallon Ziploc bags, I just pried a corner of the hose connection to the side and let the coolant seep out. Surprisingly only 1-2oz of coolant leaked out. I also made sure to clean out remaining gunk/debris from the water pump outlet port before installing the new hose.

Great tip from SAMM3Y to use a lag bolt to remove the broken plastic part from the water pump outlet. Worked great.

[PACarGuy]

Originally Posted by delirium330

Yep, having owned other BMWs, replacing the plastic bleeder screw is one of the first things I do!

I got around to doing this repair today. When parking the car in the driveway I realized it wasn't as steep as I thought and was worried I didn't have it tipped back enough. I also couldn't get it on ramps or any higher than the slight pitch of the driveway.

Went pretty smooth overall. See below picture of what I rigged to capture the fluid that would leak out. Once I had the plastic Form A Funnel in place with the gallon Ziploc bags, I just pried a corner of the hose connection to the side and let the coolant seep out. Surprisingly only 1-2oz of coolant leaked out. I also made sure to clean out remaining gunk/debris from the water pump outlet port before installing the new hose.

Great tip from SAMM3Y to use a lag bolt to remove the broken plastic part from the water pump outlet. Worked great.

Looks like you managed this w/o removing the plenum. Is that correct? Any tricks/tips?

[jun_e92]

I also had a very small coolant leak on this hose, I replaced the hose when I changed the oil filter housing and it broke inside the end head of the hose.

[jun_e92]

This is a broken inside the plastic end of the hose.

[PACarGuy]

Originally Posted by jun_e92

I also had a very small coolant leak on this hose, I replaced the hose when I changed the oil filter housing and it broke inside the end head of the hose.

Looks like a common failure. I have some weeping around my coolant overflow hose now and wondering whether I can sneak a new hose on w/o removing the plenum, though it looks pretty tough to do that way.