Coolant Level Low

[nzpanda92 16]

So something I've noticed is that my 550i seems to be drinking coolant somewhere? I get the coolant level low warning come on. When I took it in to the dealer to get it serviced, they said just to monitor it - and using distilled water to "top it up" was okay. I went on to purchase some of the BMW coolant and mixed it accordingly, and topped it up.

Generally I can go say 4-6 weeks without seeing the coolant level low message. Today I got the message again (3rd time) which makes me think perhaps there could be a leak somewhere? I'm not sure. I've had a look under the car and there hasn't been any visible leaks.

Any thoughts? Would this be something I could call my mechanical insurance guys about if its serious? Seems like even diagnosing the problem may be time consuming?

Thanks in advance - and happy driving

 

[promo 93]

if there's no obvious signs of coolant, it maybe the valley pipe (there shouldn't be any water in there. I've done a few of these with the same issue. also get the workshop to do a pressure test. 

 

[Deffed 10]

Leak down test i think its call,you can buy the system for bout $80,also need a small compressor. Pressurize each cylinder through spark plug entry hole,then observation,air leak hiss from tale pipe exhust valve's, from throttle body,inlet valves,bubbles in expansion tank,cracked head,out of oil filer or dipstick bad ring.

[KwS 2425]

1 hour ago, Deffed said:

Leak down test i think its call,you can buy the system for bout $80,also need a small compressor. Pressurize each cylinder through spark plug entry hole,then observation,air leak hiss from tale pipe exhust valve's, from throttle body,inlet valves,bubbles in expansion tank,cracked head,out of oil filer or dipstick bad ring.

Thats something completely different to finding where coolant is going...

[Deffed 10]

Realy! If you have a crack between a valve,through water jacket into the cylinder you wont get a leak,it burn in the cylinder and come out as condesation from the exhaust,thats why it takes so long for results from refill,it burning the water....🧠

 

[Deffed 10]

Pressurize cylinder,air finds fault and exits trouble spot,like hole in ballon.

[Deffed 10]

Makesure you change piston position to tdc for each cylinder. 

[jom 98]

Don't know about 550s but if it was a 2.8 I'd be looking at the low coolant sensor. life is about 3 years max.

[KwS 2425]

3 hours ago, Deffed said:

Realy! If you have a crack between a valve,through water jacket into the cylinder you wont get a leak,it burn in the cylinder and come out as condesation from the exhaust,thats why it takes so long for results from refill,it burning the water....🧠

 

These engines are known for a lot of different coolant loss situations, none of them is generally a headgasket or "crack between a valve". Stop trying to over complicate things.

As @promo said (and he knows his stuff) a coolant pressure test can show where the coolant is going, but the N62 is very well known for its valley pipe leaks (and its hard to see until its at a point of literally pouring down the front).  Just like the inevitable valve stem seal failure, almost all N62s will eventually suffer the coolant pipe failure too.

Expansion tanks are known to split and leak under heat/pressure too.

Great engines, but built to a price point, making them a POS time bomb.

Edited June 22, 2021 by KwS

[nzpanda92 16]

47 minutes ago, KwS said:

These engines are known for a lot of different coolant loss situations, none of them is generally a headgasket or "crack between a valve". Stop trying to over complicate things.

As @promo said (and he knows his stuff) a coolant pressure test can show where the coolant is going, but the N62 is very well known for its valley pipe leaks (and its hard to see until its at a point of literally pouring down the front).  Just like the inevitable valve stem seal failure, almost all N62s will eventually suffer the coolant pipe failure too.

Expansion tanks are known to split and leak under heat/pressure too.

Great engines, but built to a price point, making them a POS time bomb.

Ah yes the old valve stem seals. Was in the shop for about two weeks getting those sorted. 
 

I’m nowhere near qualified to even attempt to see what’s wrong with it. But it’s good to know what to look for. 
 

Are there any mechanics or anyone here that would know if this kinda work can be claimed under my Autosure MBI? 

[Deffed 10]

By the sound of it your already in a complicated situation, if offering advice is make it worse i look for to reading about your remadie. Good luck.👍😂

[Olaf 3317]

On 6/21/2021 at 8:46 PM, promo said:

if there's no obvious signs of coolant, it maybe the valley pipe (there shouldn't be any water in there. I've done a few of these with the same issue. also get the workshop to do a pressure test. 

 

^^ this is the correct answer.

The only reason these cars are "known for it" is that people don't follow the recommended maintenance schedule, flush and replace with Genuine BMW Coolant every two years.  I do mine annually as a precaution. As you can see in Promo's picture, someone's been running green coolant.  Probably replaced it too late.

If it is the valley pipe, there's an expanding replacement tube available in the aftermarket.

@NZPanda the way your MBI works is you put it into the workshop, they do diagnosis and liaise with your MBI provider on your behalf.  If the claim is approved, you pay your excess.

Oh - and Jom's suggestion of suspecting the sensor is also a very good one.  They're cheap and they do fail, incl the seal.

Edited June 22, 2021 by Olaf
sensor

[Olaf 3317]

PS:  

 

[nzpanda92 16]

9 hours ago, Olaf said:

@NZPanda the way your MBI works is you put it into the workshop, they do diagnosis and liaise with your MBI provider on your behalf.  If the claim is approved, you pay your excess.

Managed to speak to my service dealer and they reckon it would be covered but just want to verify that's the problem. Hopefully it's all good.

9 hours ago, Olaf said:

Oh - and Jom's suggestion of suspecting the sensor is also a very good one.  They're cheap and they do fail, incl the seal.

I was thinking about that, but did notice that my coolant tank was rather low when the message did show up.

[nzpanda92 16]

9 hours ago, Olaf said:

PS:  

 

aw man definitely sounds like a big job for the dealer! BMW dealers would never use this right? Their mandate is to fix it with OEM parts?

[Gaz 1061]

2 hours ago, nzpanda92 said:

aw man definitely sounds like a big job for the dealer! BMW dealers would never use this right? Their mandate is to fix it with OEM parts?

Depends on the dealer, some are ok others may not

[Deffed 10]

Iv asked my local bmw dealer techs some pritty straight forward questions and they've ether said that there not sure,or that it wont work. Example, m54b30 i have 2 engins 98,04 had issues with o2 sensor, they have 2 different o2 sensors,different plug input,different diameter. 04 different 90mm diameter, asked would smaller one run the engine, the dude laught down the phone, said silly idea and no wont happen. So installed smaller o2 sensor, runs mint.

[Olaf 3317]

As in any part of life where there’s expertise in servicing any equipment (not just BMWs), there’s excellence and something that passes for service, and plenty of arrogance in between at both ends of that continuum, and in between.

[nzpanda92 16]

So just updating this - took it into BM Workshop this morning (read about them on the forums). Found the expansion tank was leaking. Booked in for next week to get sorted, and is hopefully covered under Autosure's MBI (apparently they need to send an inspector out to have a look and judge whether its covered or not).

I do have to say - the people at BM Workshop have been really helpful and pleasant to deal with. Will definitely be going back there to carry out any other work on the car.

[nzpanda92 16]

Another update in the coolant level low saga. 

The wonderful guys at BM Workshop replaced the expansion tank on the 550i without too many issues. Autosure did ask for proof for service history to make sure I was sticking to my service requirements.

Anyway, Sunday morning I went to hop in my car and go for a drive. After parking up at the supermarket for about a half hour, I got back in and the ol' iDrive came up with a low coolant message again. Luckily I lived a 5min drive away so quickly shot home and let it cool down. After an hour or so I opened the expansion tank to find it really low - almost empty (noting that it was filled up when I had the tank replaced). I didn't have any coolant on me, so just topped it up with a bit of demineralized water and left it overnight. 

This morning when i went down to the garage I found that the car had leaked coolant all over the floor (hadn't done that in the last few days). Threw a bit more demineralized water into it and drove to BM Workshop (another 5 min drive from me). They checked it out today and informed me that it had a leaking heater tap assembly and is covered under Autosure as well.

Forgive me for not knowing as I have bugger all knowledge of cars/engines etc, but what is the function of a heater tap? How do they work?

[Deffed 10]

51 minutes ago, nzpanda92 said:

Another update in the coolant level low saga. 

The wonderful guys at BM Workshop replaced the expansion tank on the 550i without too many issues. Autosure did ask for proof for service history to make sure I was sticking to my service requirements.

Anyway, Sunday morning I went to hop in my car and go for a drive. After parking up at the supermarket for about a half hour, I got back in and the ol' iDrive came up with a low coolant message again. Luckily I lived a 5min drive away so quickly shot home and let it cool down. After an hour or so I opened the expansion tank to find it really low - almost empty (noting that it was filled up when I had the tank replaced). I didn't have any coolant on me, so just topped it up with a bit of demineralized water and left it overnight. 

This morning when i went down to the garage I found that the car had leaked coolant all over the floor (hadn't done that in the last few days). Threw a bit more demineralized water into it and drove to BM Workshop (another 5 min drive from me). They checked it out today and informed me that it had a leaking heater tap assembly and is covered under Autosure as well.

Forgive me for not knowing as I have bugger all knowledge of cars/engines etc, but what is the function of a heater tap? How do they work?

Assumption is eather a drain or a switch to stop water entering heater core. I have 330i had issues with cooling system,unfortunately the plastic parts all seem to fail at the same time and ensuring you bleed all the air out is a must. Unscrew bleed point keep filling it up till I over flows out the bleed point and the top of expansion tank. Start it up, be ready with coolant as soon as it starts dropping put more in so it can't put any more in.

[jon dee 500]

2 hours ago, nzpanda92 said:

.... what is the function of a heater tap? How do they work?

Heater tap is a generic term for whatever mechanical/electrical or pneumatic device that controls the flow of hot coolant into the heater. This is apparently what you have on a 550i...

Appears to be two solenoid valves that work like a mixing valve to send coolant with the correct temperature to the heater.

Cheers...