[sam555]

So I got the dreaded low coolant warning on my 2020 M550 after starting cold after about 4 days.

Car has about 42K miles. I've read all the stuff online about potential coolant issues. My turbo lines etc. are metal, and there doesnt seem to be any leak there on visual inspection.

There was however some white, crusty stuff on top of the coolant tank, and when I opened the cap, a lot of that on top. Attached is a pic.

My question is as follows. My CPO expires in Sept 2024. I understand CPO doesn't cover hoses, but would it cover it in this case? Would CPO cover any other problems - such as cracks etc in the coolant tank? I am hoping mine is an instance of just a bad fitting cap, since so much seems on top!

I dont want the dealer blowing me off with the usual these cars burn coolant etc. I would like them to take a serious look and do whatever needs to be done and replace necessary parts, hopefully under CPO. How do I ensure they do it? What do I tell them etc? Any advise would be appreciated.

Thank you in advance as always!

[adhrp]

I'm at the dealership as we speak dropping off my car for my 2nd low coolant warning in less than a year. First one was coolant expansion tank leaking, replaced under warranty. Now it's the upper expansion tank hose that goes to the cylinders that is leaking. This isn't covered and is costing me $1200 out of pocket after the dealer reduced the original quote from 1700. Two respected indys in my city also quoted me $1200. The part is 75 bucks.. Rest is labor given what a labyrinth this engine is. They have to remove lots of components to get to the hose. Let's hope yours is not a leaking hose.

[sam555]

Originally Posted by adhrp

I'm at the dealership as we speak dropping off my car for my 2nd low coolant warning in less than a year. First one was coolant expansion tank leaking, replaced under warranty. Now it's the upper expansion tank hose that goes to the cylinders that is leaking. This isn't covered and is costing me $1200 out of pocket after the dealer reduced the original quote from 1700. Two respected indys in my city also quoted me $1200. The part is 75 bucks.. Rest is labor given what a labyrinth this engine is. They have to remove lots of components to get to the hose. Let's hope yours is not a leaking hose.

adhrp I am very sorry to hear. I hope this resolves it for you. I am visiting the dealer tomorrow. Saw some some other posts on the forum which I missed earlier. Seems like this is just waiting to happen on the M550.

[HerkHealer]

It's just stupid that BMW has not offered a TSB or Recall on this.
They obviously know it's an engineering fail, yet they tell the SA's to tell us "it's normal for V8's to eat coolant".
LOL

[adhrp]

Originally Posted by sam555

adhrp I am very sorry to hear. I hope this resolves it for you. I am visiting the dealer tomorrow. Saw some some other posts on the forum which I missed earlier. Seems like this is just waiting to happen on the M550.

Keep us posted on what they find/say.

[Joe-BMW33]

CPO covers hoses and lines. Aftermarket warranties sometimes do not. You should be covered no matter which coolant issue it is, tank, lines, etc.

[NGT2]

It’s a leak. Don’t let them tell you otherwise. On my first warning I was told it evaporates blah blah which I knew was BS. But I had a year of warranty left and my SA said we would top it off and document it and if we got the light again it would warrant a more thorough exam. I had over a year left of warranty so I at least knew I’d be covered if it caused more problems. Got it again right before going in for oil service anyway. Sure enough, they found the tank was leaking at the seam.

Its the same pattern over and over. They finally put out a TSB and a stop sale on F90 M5 and M8. But theirs is a different tank.

Also, my warnings both showed up after not driving for a couple days. Not sure why that contributed to the leak showing itself but it seems it did.

[sam555]

So they did not find anything. The pressure test showed no drop in pressure over 10 mins. Visual inspection showed no hoses leaking etc. In a way I am relieved. FYI, this was posted on another list in response to my concern, from the repair manual for the G30 M550. It says the cap has some kind of release valve. I'm no expert here, but this was interesting.

"Check the cooling system for watertightness with the special tool

GRA-SYM-GRCI0000-10-INFO

TECHNICAL INFORMATION
If the described test step is not completed successfully: repeat test step twice. Only replace the sealing cap after three tests with an incorrect opening pressure.
When driving at high ambient temperatures, the design may cause the pressure relief valve in the sealing cap to open slightly and air to escape together with dissolved coolant. This coolant vapour condenses on the surface of the coolant expansion tank and leaves traces of coolant when the vehicle has cooled down. These traces of coolant do not indicate whether the sealing cap is defective or not.
Escaping coolant vapours when the vehicle is at standstill may cause the pressure relief valve to stick to the sealing cap. This may cause an incorrect opening pressure. "

[NGT2]

I still don’t believe it evaporates but I have read of caps being loose or defective. And you had residue there so it makes sense. Did they replace the cap or say anything about it not being on tight?

[sam555]

No, they didnt say anything about the cap being bad. And the coolant pump weep hole may allow some coolant loss even when things are fine. So this whole system is not closed and hence coolant loss is possible. Finding out all of this from another list and thanks to the folks there. NGT2

[NGT2]

Originally Posted by sam555

No, they didnt say anything about the cap being bad. And the coolant pump weep hole may allow some coolant loss even when things are fine. So this whole system is not closed and hence coolant loss is possible. Finding out all of this from another list and thanks to the folks there. NGT2

Good to know!

[MrLatte]

Originally Posted by NGT2

I still don’t believe it evaporates but I have read of caps being loose or defective. And you had residue there so it makes sense. Did they replace the cap or say anything about it not being on tight?

This

[Chappers 71]

Am afraid it doesn’t matter what some of you guys may or may not believe, there will be some evaporation of the water in the coolant, fact. Now obviously if you’re topping up every month or so there’s an issue…but some ‘coolant’ will be lost due to evaporation through hoses & expansion tank walls, especially in very hot conditions….don’t have to take my word for it, a little Googling will confirm

[Joe-BMW33]

Originally Posted by Chappers 71

Am afraid it doesn’t matter what some of you guys may or may not believe, there will be some evaporation of the water in the coolant, fact. Now obviously if you’re topping up every month or so there’s an issue…but some ‘coolant’ will be lost due to evaporation through hoses & expansion tank walls, especially in very hot conditions….don’t have to take my word for it, a little Googling will confirm

Of course Chaps, but we are talking years (many) before the low coolant warning would go on for evaporation, not months.

[Chappers 71]

Originally Posted by Joe-BMW33

Of course Chaps, but we are talking years (many) before the low coolant warning would go on for evaporation, not months.

Agreed but the cars new to OP & there’s no info on when it last had coolant ( & water) added. Hopefully now it’s been topped up it’ll be ok.
I check mine every month or so, actually checked this morning before I took the G31 out & levels are good, no noticeable loss from when I last topped up

[Drifttime85]

I’ve got my own thread about my coolant leak and response from my dealership. I just feel like with 8 months in a brand new car, I shouldn’t have any low coolant lights. It’s one thing if I tracked or raced the car on a regular basis but this is literally my daily cruiser from work and back. I don’t mind filling my coolant if need be but definitely would love to know the root cause.

[adhrp]

Originally Posted by Chappers 71

Am afraid it doesn’t matter what some of you guys may or may not believe, there will be some evaporation of the water in the coolant, fact. Now obviously if you’re topping up every month or so there’s an issue…but some ‘coolant’ will be lost due to evaporation through hoses & expansion tank walls, especially in very hot conditions….don’t have to take my word for it, a little Googling will confirm

Hmm none of my cars (each owned for a decade almost) needed coolant, including my F30 328i that I owned for 8 years and 130k+ miles. Never changed the hoses or tanks either.

[Joe-BMW33]

Originally Posted by Drifttime85

I’ve got my own thread about my coolant leak and response from my dealership. I just feel like with 8 months in a brand new car, I shouldn’t have any low coolant lights. It’s one thing if I tracked or raced the car on a regular basis but this is literally my daily cruiser from work and back. I don’t mind filling my coolant if need be but definitely would love to know the root cause.

You are exactly right. You should not be adding coolant in an 8 month old car. Think about, have you EVER had to do this for any other car in your history?

[adhrp]

Originally Posted by Drifttime85

I’ve got my own thread about my coolant leak and response from my dealership. I just feel like with 8 months in a brand new car, I shouldn’t have any low coolant lights. It’s one thing if I tracked or raced the car on a regular basis but this is literally my daily cruiser from work and back. I don’t mind filling my coolant if need be but definitely would love to know the root cause.

Root cause = leak. Might be slow but there's a leak. My dealership seems to be good at finding them. First time it was the expansion tank, the second time it was the upper expansion tank hose that goes to the cylinder. I think I was lucky in that the hose leak was up top. I think most folks get the runaround because no dealership wants to take apart all the pieces to find leaks deeper in the labyrinth of the engine for a $200 diagnostic fee. Pressure tests don't always catch those slow leaks without a visual confirmation of coolant seeping out, I think.

[Drifttime85]

Originally Posted by Joe-BMW33

You are exactly right. You should not be adding coolant in an 8 month old car. Think about, have you EVER had to do this for any other car in your history?

Exactly. Never in any of my turbo cars. And ive had big snails before.

Originally Posted by adhrp

Root cause = leak. Might be slow but there's a leak. My dealership seems to be good at finding them. First time it was the expansion tank, the second time it was the upper expansion tank hose that goes to the cylinder. I think I was lucky in that the hose leak was up top. I think most folks get the runaround because no dealership wants to take apart all the pieces to find leaks deeper in the labyrinth of the engine for a $200 diagnostic fee. Pressure tests don't always catch those slow leaks without a visual confirmation of coolant seeping out, I think.

They did the pressure test and said no leaks like you said. Do you know of something I can request additionally that I can pay out of pocket ? I don’t want to run into a bigger issue out of warranty.

[Chappers 71]

Originally Posted by adhrp

Hmm none of my cars (each owned for a decade almost) needed coolant, including my F30 328i that I owned for 8 years and 130k+ miles. Never changed the hoses or tanks either.

Hmm…I’ve owned BMWs since 1995 & have on occasion added coolant to all of them & just take it as the norm & regularly check levels & top up if needed. Have never had a low coolant warning though, well not without something having failed, top hose letting go on the e39 540i at motorway speed…didn’t need the low coolant warning for that one
I guess we all have different experiences

[adhrp]

Originally Posted by Chappers 71

Hmm…I’ve owned BMWs since 1995 & have on occasion added coolant to all of them & just take it as the norm & regularly check levels & top up if needed. Have never had a low coolant warning though, well not without something having failed, top hose letting go on the e39 540i at motorway speed…didn’t need the low coolant warning for that one
I guess we all have different experiences

Key words highlighted I never look into the coolant reservoir on any of my cars, but without a warning I suppose it was all within acceptable limits/levels. My mechanic also didn't spot any coolant leaks anywhere (and believe me I over-maintained my 328i and he had plenty of looks inside the engine). That's what I am referring to when I say "coolant loss".