[XutvJet]

Over on the 3/4 series forum they're now starting to replace turbos for this issue. Apparently the turbo bearing is leaking coolant into the turbo and being burned up.

http://f30.bimmerpost.com/forums/sho...1324221&page=5

[amw896]

M3/M4 forums are showing coolant being ingested in through the intake valves. I don't know, every indy shop I've talked to has always said coolant loss is a big deal. Unless it's leaking from the tank or hoses.

Apparently, m3 owners are being told coolant going through the intake is not that big of a deal.....

Originally Posted by XutvJet

Over on the 3/4 series forum they're now starting to replace turbos for this issue. Apparently the turbo bearing is leaking coolant into the turbo and being burned up.

http://f30.bimmerpost.com/forums/sho...1324221&page=5

[XutvJet]

Originally Posted by amw896

M3/M4 forums are showing coolant being ingested in through the intake valves. I don't know, every indy shop I've talked to has always said coolant loss is a big deal. Unless it's leaking from the tank or hoses.

Apparently, m3 owners are being told coolant going through the intake is not that big of a deal.....

Some minor evaporation is normal since coolant in 50%+ water; however, BMWs and most German makes use nearly air tight overflow/expansion tanks, thus evaporation should very very minimal. I'd say if you're loosing even a cup of coolant a year in a newer BMW, it's a cause for alarm. All my current and prior Japanese cars have non-air tight expansion tanks and they routinely loose 1/2 cup of water (i.e. coolant) every 3 to 6 months.

As for the M3/M4, if coolant is going though the intake valves then that means there's a leak in the liquid/air intercooler setup. That's even more frightening than a leaking turbo because then there's a real risk of hydro-lock and total engine failure if the leak were to increase. The B58 uses a similar liquid/air intercooler setup as the M3/M4 and it's intake manifold is full of coolant (scary).

Since most people seem to be loosing coolant from the smaller expansion tank that feeds the turbo, I'm more inclined to believe that there's a problem with the turbo bearing/seal. It makes sense too as the turbo expansion tank only feeds the turbo. It's less concerning to have a leak at the turbo rather liquid/air intercooler given the potential failure points. A longterm coolant leak at the turbo will eventually kill the turbo and that's pricey ($4K+). A larger coolant leak into the motor could mean $25K for a new shortblock and head.

The B58 is a great performing motor, but some of it's designs, especially regarding it's elaborate cooling systems, rear mounted timing chain and oil cooler, give me great pause owning one of these motors outside of warranty.

[amw896]

Right?! Sounds a lot more concerning than the dealer is making it seem.

http://f80.bimmerpost.com/forums/sho...1433364&page=2

Pics are on page 2. Worst part is, they just changed the oil so an UOA coundn't be done.

[XutvJet]

Originally Posted by amw896

Right?! Sounds a lot more concerning than the dealer is making it seem.

http://f80.bimmerpost.com/forums/sho...1433364&page=2

Pics are on page 2. Worst part is, they just changed the oil so an UOA couldn't be done.

You're spot on with the oil concern. Think about the potential risk to something like the rod bearings? Yikes.

Per the link below, unlike the M3/M4, removing the intake pipe on the B58 would not help you diagnose a air/liquid intercooler leak issue because the intercooler is integrated directly into intake manifold itself. If this system was leaking, you'd need to remove the intake manifold to see if there was coolant entering the intake valve ports.

The link also shows the turbo coolant system setup and how it assists in cooling the turbo bearing. In BMW's eyes, the turbo and exhaust manifold are one part and not bench serviceable. That's why so expensive to replace a turbo on these cars if you go about it the factory way. It's the same way with the N54 and N55 motors.

http://f30.bimmerpost.com/forums/sho....php?t=1133836

[TajoMan]

Under normal circumstance, coolant level shouldn't go down at all.
It may lose very small amount of water, which typically means the expansion tank cap is leaking. (either seal or not tightened enough)
In this case it may lose very small amount over long period of time. (<50 ml per yr)

If the you keep losing coolant, it means it must be leaking somewhere.

If the coolant level is good after you fill up once or twice, it can be considered as improper fill at the factory. (as long as you don't lose coolant continuously)

BMW factory coolant fill is not that reliable.
(I had issues with my wife's 2013 X3 N55, filled up twice then it was ok until the coolant pump failed at 55k miles)

They should bleed properly or vacuum fill it.

[ingleberg1]

Took my M240i in for a coolant warning at approx 6 months/2500 miles. They blamed it on the cool weather. Well now it's in the 100's in Texas, and the warning started coming up again. Dealer said they topped it off and ran a pressure test... and sent me home with a jug of coolant. Said that was all they could do. How is this acceptable for a $53k car?

[TajoMan]

Originally Posted by Mr Carrots

I needed an engine replacement after the coolant issue came up. Don't let BMW dealers BS you, there are obviously serious material issues with at least up to 2017 b58s

I hope your case is one of the rare instance.
(At least I don't see a lot of engine replacement thread due to coolant leaking)

Of course, we shouldn't let the dealer BS about potentially serious problem.

[PeterWT]

I haven't gotten a coolant low warning, but I checked both reservoirs and they were both low. I brought the car in for an oil change and asked them to check and top off, so they did. I also asked why it's "using" coolant. It shouldn't. The SA said it's common on the B58, they see it a lot. No explanation.

[loudiamond15]

So I first started researching this issue about 2 months ago when I took my 2018 M240i in for its first scheduled service at 9k miles. I started getting the low coolant warning about a week before my appointment. Like most others I read about, I checked both reservoirs and the main one was indeed under the "low" mark. As instructed by the stealership's service department, I topped her off with distilled water until they could get a look at it in a week's time. I did that and did not have the coolant warning come back. I also had no evidence whatsoever of any leaking anywhere I parked. I took it in for the appointment and the tech said the same as most have posted, that it was most likely slight evaporation and wasn't completely topped off from the dealer and there were no leaks of any kind anywhere. I kept a keen eye on it for the next month and saw no issues so I thought nothing more of it.

Fast forward to this past weekend. I took a short trip to a friend's Christmas party who lives about 2 hours away (125 miles one way). I get back into town and right as I'm on my last 5 miles of the trip, the coolant warning comes on again. I get home, park and within minutes I could see a pool forming under the front left (if you're looking at the headlights). I thought it may be water condensation from running the A/C, but nope, it definitely had a blue tint. After the car cooled down enough to check late that night I confirmed that the main reservoir was below the "low" mark again considerably. I called the stealership's service department this morning and scheduled to take it in. It's currently sitting there waiting for assessment.

For reference, I don't drive the car hard a lot. Mostly the only time I really get on it is when I'm merging onto the interstate going to and from work each day. I'd say it's about a 50/50 mix of highway/in-town driving. I just passed 11000 total miles. No mods of any kind, so it's straight factory. I'll update this when I get word back from the service department.

[Dj_Quik]

Same thing happened to me. Losing coolant every couple days. Jb4 indicating my intake air temps were unusually high even when driving on the hway and my radiator fan going on full speed all the time. Brought it in the dealership and lo and behold i had a hole in my radiator from a small rock hitting it. Apparently its common on b58 powered cars. Not covered under warranty but part of the cost was good willed by bmw canada because the issue is so common.

[loudiamond15]

So I got a call from the stealership Tuesday morning. They found there was a puncture in my radiator which looked like it had been caused by a rock or some other debris from the road kicking up and hitting it. So either I am the unluckiest person in the world or there is a serious design flaw that would allow for something like this to happen. Long story short, it's not covered by warranty and oddly enough it appears it was not related to my initial low coolant issue a couple months ago. Either way, I'll still be keeping an eye on the coolant levels moving forward.

Originally Posted by loudiamond15

So I first started researching this issue about 2 months ago when I took my 2018 M240i in for its first scheduled service at 9k miles. I started getting the low coolant warning about a week before my appointment. Like most others I read about, I checked both reservoirs and the main one was indeed under the "low" mark. As instructed by the stealership's service department, I topped her off with distilled water until they could get a look at it in a week's time. I did that and did not have the coolant warning come back. I also had no evidence whatsoever of any leaking anywhere I parked. I took it in for the appointment and the tech said the same as most have posted, that it was most likely slight evaporation and wasn't completely topped off from the dealer and there were no leaks of any kind anywhere. I kept a keen eye on it for the next month and saw no issues so I thought nothing more of it.

Fast forward to this past weekend. I took a short trip to a friend's Christmas party who lives about 2 hours away (125 miles one way). I get back into town and right as I'm on my last 5 miles of the trip, the coolant warning comes on again. I get home, park and within minutes I could see a pool forming under the front left (if you're looking at the headlights). I thought it may be water condensation from running the A/C, but nope, it definitely had a blue tint. After the car cooled down enough to check late that night I confirmed that the main reservoir was below the "low" mark again considerably. I called the stealership's service department this morning and scheduled to take it in. It's currently sitting there waiting for assessment.

For reference, I don't drive the car hard a lot. Mostly the only time I really get on it is when I'm merging onto the interstate going to and from work each day. I'd say it's about a 50/50 mix of highway/in-town driving. I just passed 11000 total miles. No mods of any kind, so it's straight factory. I'll update this when I get word back from the service department.

[Hpirx]

So apparently BMW radiators have a strength somewhere between spun sugar and feta cheese!
This happened to me on the Hutchinson River Parkway last spring in my '08 335.
Weird because it has a plastic belly pan and sits back from the grill.
Dad's indy shop, deep in the woods of Katonah, diagnosed it as a screwdriver puncture from a recent sparkplug change at my indy on LI. Iatrogenic wrenching for you healthcare types.
Looking for better luck with a NEW 2 series.