[Si-M240i]

My 2018 LCi M240i has been using coolant for over a year and it's been to dealership twice and pressure tested and no leaks anywhere. I have Just tested its consumption over 1000 miles and is used 20ml in the small reservoir and 120ml in the large reservoir. A total of 140ml in 1000 miles..... that's 1.4 litres in 10,000miles !!! It's booked back in with BMW but I'm worried they will say it's normal again and no fault found . That amount of coolant loss is definitely not normal. Anyone got any ideas as dealership say they have never seen this issue before. I can only think the engine is using it. Turbo issue around the seals for water cooling maybe? I don't have any emulsification in the oil filler cap so it's not getting past the head gasket into an oil feed

[m240nj]

Originally Posted by Si-M240i

My 2018 LCi M240i has been using coolant for over a year and it's been to dealership twice and pressure tested and no leaks anywhere. I have Just tested its consumption over 1000 miles and is used 20ml in the small reservoir and 120ml in the large reservoir. A total of 140ml in 1000 miles..... that's 1.4 litres in 10,000miles !!! It's booked back in with BMW but I'm worried they will say it's normal again and no fault found . That amount of coolant loss is definitely not normal. Anyone got any ideas as dealership say they have never seen this issue before. I can only think the engine is using it. Turbo issue around the seals for water cooling maybe? I don't have any emulsification in the oil filler cap so it's not getting past the head gasket into an oil feed

Went through the same ordeal for two years. Each time they pressure tested and found no leaks. Finally after the fifth time of needing to add coolant, they all the sudden found a hole in the lower radiator. Quoted me at some insane price to replace it. It ended up being a whole long ordeal so hopefully that's not your issue. These cars are infamous for lower radiator damage prior to model year 2018 since they began installing protective screens in front of the radiator beyond 2017. Check to see if you have the screen. If not, I'm willing to bet it's cracked somewhere.

[dradernh]

Originally Posted by sec5197

These cars are infamous for lower radiator damage prior to model year 2018 since they began installing protective screens in front of the radiator behind 2017. Check to see if you have the screen.

I just had the rock guard installed on my car. It wasn't cheap. They removed the intercooler and radiator along the way, as well as replacing the coolant.

The issue has been discussed at length on BabyBMW.net – this is the principal thread: https://www.babybmw.net/viewtopic.php?f=74&t=110573.

[NISFAN]

Originally Posted by Si-M240i

My 2018 LCi M240i has been using coolant for over a year and it's been to dealership twice and pressure tested and no leaks anywhere. I have Just tested its consumption over 1000 miles and is used 20ml in the small reservoir and 120ml in the large reservoir. A total of 140ml in 1000 miles..... that's 1.4 litres in 10,000miles !!! It's booked back in with BMW but I'm worried they will say it's normal again and no fault found . That amount of coolant loss is definitely not normal. Anyone got any ideas as dealership say they have never seen this issue before. I can only think the engine is using it. Turbo issue around the seals for water cooling maybe? I don't have any emulsification in the oil filler cap so it's not getting past the head gasket into an oil feed

Define your filling habits.

In my experience (engine - large rear tank), if you fill to the full mark when cold, the system will vent some coolant until it's back down around the low fill mark. It will keep doing this no matter how many times you keep topping it up. However, if you're saying when you don't top up it keeps disappearing and you get low level alarm then for sure you have an active (abnormal) coolant loss.

[Si-M240i]

Originally Posted by NISFAN

Define your filling habits.

In my experience (engine - large rear tank), if you fill to the full mark when cold, the system will vent some coolant until it's back down around the low fill mark. It will keep doing this no matter how many times you keep topping it up. However, if you're saying when you don't top up it keeps disappearing and you get low level alarm then for sure you have an active (abnormal) coolant loss.

I fill it to the max mark and in about 1000miles it just above the minimum mark, so I top it up again. BMW have a service bulletin to say to fill 200ml above the maximum level!

[Si-M240i]

Originally Posted by dradernh

I just had the rock guard installed on my car. It wasn't cheap. They removed the intercooler and radiator along the way, as well as replacing the coolant.

The issue has been discussed at length on BabyBMW.net – this is the principal thread: https://www.babybmw.net/viewtopic.php?f=74&t=110573.

Mine is a late March 2018 LCi so hopefully I have the guard you mentioned. Do you have a picture of what I'm looking for?

[NISFAN]

Originally Posted by Si-M240i

I fill it to the max mark and in about 1000miles it just above the minimum mark, so I top it up again. BMW have a service bulletin to say to fill 200ml above the maximum level!

Why not try leaving it? IMO you are continually topping up the spill off. I bet you have residue around the cap? Clear sign of natural venting.

[Si-M240i]

Originally Posted by NISFAN

Why not try leaving it? IMO you are continually topping up the spill off. I bet you have residue around the cap? Clear sign of natural venting.

Nope nice and clean around the filler cap. I even fitted a new cap before doing my 1000 mile test

[dradernh]

Originally Posted by Si-M240i

Mine is a late March 2018 LCi so hopefully I have the guard you mentioned. Do you have a picture of what I'm looking for?

I do; unfortunately, I don't have any 'before' photos. Here they are:

Upper Grille Opening After Rock Guard Installation


Lower Grille Opening After Rock Guard Installation

[Si-M240i]

Originally Posted by dradernh

I do; unfortunately, I don't have any 'before' photos. Here they are:

Upper Grille Opening After Rock Guard Installation


Lower Grille Opening After Rock Guard Installation

Ah, I thought you meant an oem version. I am in the process of buying mesh to do this too. Just need to see if I can remove my lower grilles again as they were a pig to replace and I don't want to take the bumper off

[Si-M240i]

Originally Posted by Si-M240i

Ah, I thought you meant an oem version. I am in the process of buying mesh to do this too. Just need to see if I can remove my lower grilles again as they were a pig to replace and I don't want to take the bumper off

The centre one I may fit the mesh on the outside with cable ties and put some edging around it to make it look neater

[dradernh]

Originally Posted by Si-M240i

I fill it to the max mark and in about 1000miles it just above the minimum mark, so I top it up again. BMW have a service bulletin to say to fill 200ml above the maximum level!

Originally Posted by NISFAN

Why not try leaving it? IMO you are continually topping up the spill off. I bet you have residue around the cap? Clear sign of natural venting.

Another data point, in the event it's of use: I follow the recommendation of Mike Miller* to keep my coolant level between MIN and MAX. After setting it there, that's where it remains, whether I'm just driving on the highway or I've run it at the track.

My dealer must follow the 200ml above MAX direction, as that's pretty much how it's come back after the two coolant changes I've had.

* Mike is the Technical Editor for the BMW Car Club of America's Roundel Magazine. His rationale is based upon the years (decades?) of BMW cooling system issues. Mike's thinking is that somewhat less coolant (but not too little!) will result in less pressure in the system, followed by fewer cooling system failures.

[dradernh]

Originally Posted by Si-M240i

Ah, I thought you meant an oem version. I am in the process of buying mesh to do this too. Just need to see if I can remove my lower grilles again as they were a pig to replace and I don't want to take the bumper off

No, no...forget the mesh in front; what you're meant to look at is the radiator-like panel behind it. That's the rock guard, both top and bottom. Sorry for the confusion!

[Si-M240i]

Originally Posted by dradernh

No, no...forget the mesh in front; what you're meant to look at is the radiator-like panel behind it. That's the rock guard, both top and bottom. Sorry for the confusion!

Lol. The have that plastic frame on my lower radiator for sure

[dradernh]

Originally Posted by Si-M240i

The centre one I may fit the mesh on the outside with cable ties and put some edging around it to make it look neater

That would certainly be easier and much cheaper than the route I took. I spent $710 / £550 getting that rock guard installed.

But, I did get another coolant change out of it!

[Si-M240i]

Originally Posted by dradernh

That would certainly be easier and much cheaper than the route I took.

I have found black aluminium mesh and some "U" profile rubber edging that I am hoping I can wrap around the outside edge to make it neat and then a few black cable ties to fit it to the plastic oem grille. The lower side ones I hope to be able to remove and the kidney grilles cone out easy anyway