HELP NEEDED! Z4 E89 30iSDrive - Pink coolant after engine flush by workshop?!

[Scooba_Steve]

Well, I have just left the workshop and the manager told me that they would flush it again and put the, G48 instead.
He told me that the coolant was correct (I guess to save face) in spite of the colour but agreed to do another flush and fill up with blue G48.

Does sound like, BS. Otherwise why change it...

He said that the residue was due to the product used in the flushing, which takes a little while to fully eliminate, picking up grime, etc... from the bowels of the coolant system and then finding its way to the expansion tank.

Perhaps. But then why not advise that at the time and suggest coming back for another coolant change in a month or so? And being transparent at the time, e.g. "we advise using this flush. If we do you may find small contamination and if you want to be sure it's all gone then come back for another change".

A coolant change at the dealer might not have been that much more to be honest. It's always worth a quote, sometimes they have deals on e.g. proper air con clean for £45.

I will try to do as much of the work as my ability allows me.

That's what this place is for, expand that ability!

If you have an air compressor, a coolant vac filler is well worth getting.

[Varixto]

In the end they flushed it again and they replaced the coolant. They assured me that it was G48 but I am getting paranoid paranoid and am thinking that they could have put G11, which is also blue... Is there any way of telling? Does it matter if I mix G11 with G48?

At least the slimy residue seems to have gone and now the coolant has a clear colour...
This is what it looks like now.
The phone's pic. seems to distort the colours a bit. In reality, it looks a bit different. It has a greyish, almost dark greenish tint.

20250521_210152.jpg (90.93 KiB) Viewed 488 times

What do you guys think?

[Scooba_Steve]

It has a greyish, almost dark greenish tint.

Probably OK then.

If it was the same colour as the pic I'd say it was G11 which is definitely not compatible as it contains Borate.

If it's going to bother you then the only choice is to drop it and refill. It's an easy, if messy, DIY. With the electric pump you can at least flush easily.

You can drain (obviously not all comes out) refill with plain water, run the pump, drain, repeat then put in half the total volume of concentrate and finally top up with water.

[Pondrew]

It's always worth a quote, sometimes they have deals on e.g. proper air con clean for £45.

I would love to know what this 'proper air con clean' involves for £45.00.
The only things you can 'clean' on a car's a/c system are the evaporator coil and/ or the condenser coil. To 'properly' clean the evaporator coil involves a LOT of work. The entire dash needs to come out, for starters. To clean the condenser coil involves quite a bit aswell. Neither are something any car garage will a) know how to do IME and b) if they did they would be charging for 5 hours plus work and materials.

The last time I did a 'proper' clean on an car's a/c system it took nearly all day. So at dealer rates that around £2,000.00

I would guess that the 'proper air con clean' (for £45) will involve them sticking one of those anti-bacterial 'bombs' inside the car and running the a/c on recirc for half an hour. You can do that yourself for a fiver. That is far from a 'proper' clean, though.

[Pondrew]

What do you guys think?

I think you need to have something more important to worry about TBH. Fussing about which colour or 'G' number is in your car is mad.
It's coolant!
It's a mixture of water and anti-freeze. No matter what the marketing people want to tell you, it's (unleaded) water with some chemicals in to a) stop it freezing in Winter and b) stop the anti-freeze eating away your engine block, water pump impellor, radiator and heater matrix. That is it!

As long as the mixture of different coolants in the system don't react with each other too much to a) turn to jelly and clog the system or b) eat your block away it will be OK. Both the previous scenarios are very, very, very unlikely. Different chemical make-ups of coolants are more to please the 'environment' than the car TBH.

[2k35is]

[
[/quote]
I think you need to have something more important to worry about TBH. Fussing about which colour or 'G' number is in your car is mad.
It's coolant!

As long as the mixture of different coolants in the system don't react with each other too much to a) turn to jelly and clog the system or b) eat your block away it will be OK. Both the previous scenarios are very, very, very unlikely. Different chemical make-ups of coolants are more to please the 'environment' than the car TBH.
[/quote

No specific knowledge but do know that N52 block is made from aluminums and magnesium - one of the lightest six cylinder blocks in existence apparently.
Could this be why a specific coolant is required- never thought about it before- I've got same engine in my 125i and used Prestones yellow coolant in it. Even had a look for spec in cars handbook says to ask dealer.
So anyone know definite answer

[B21]

Big big problem with engines with mixed aluminium / magnesium castings …they can suffer from rabid corrosion if the right inhibitors are not added..we had lots of issues with the Mercedes based engines with this..for those in the end they put a pouch of extra inhibitors in the coolant circuit..

No point in not using the correct stuff..

[Varixto]

Big big problem with engines with mixed aluminium / magnesium castings …they can suffer from rabid corrosion if the right inhibitors are not added..we had lots of issues with the Mercedes based engines with this..for those in the end they put a pouch of extra inhibitors in the coolant circuit..
No point in not using the correct stuff..

I think exactly the same! I did not want to mix coolants inadvertently and reduce the corrosion-inhibiting properties of the coolant. I don't skimp on anything related to car maintenance and always use either OEM or with OEM specs.
You told me in a previous post what the correct coolant spec. was. I assumed that a BMW "specialist" would also know... so I did not mention it when booking for the flush. Well, lesson learnt.

[Varixto]

I received confirmation this morning that they used the BMW's OEM coolant: LT Coolant 87 G84 spec. BMW part Number 83515A6CDD7
Well, it seems that now it's all good...
But I have been left thinking that had I been a person with 0% knowledge of cars (most people) and with a black coolant expansion tank where you can't see what they put in there unless you take the trouble to open it and check with a syringe or something like that...they would have got away with it!
And I am sure that they knew that the coolant they put was not of the correct spec. I am inclined to think that they simply thought that they would get away with it...
They were quick to rectify the problem and were pleasant to deal with. They had been very good when they fixed the leak in the boot that destroyed my parking brake EMF module. However, all this has made me think of taking my car elsewhere whenever I have to carry out any work on the car. The problem is that I'm trapped, as they're the only BMW specialists in my town.

[B21]

I received confirmation this morning that they used the BMW's OEM coolant: LT Coolant 87 G84 spec. BMW part Number 83515A6CDD7
Well, it seems that now it's all good...
But I have been left thinking that had I been a person with 0% knowledge of cars (most people) and with a black coolant expansion tank where you can't see what they put in there unless you take the trouble to open it and check with a syringe or something like that...they would have got away with it!
And I am sure that they knew that the coolant they put was not of the correct spec. I am inclined to think that they simply thought that they would get away with it...
They were quick to rectify the problem and were pleasant to deal with. They had been very good when they fixed the leak in the boot that destroyed my parking brake EMF module. However, all this has made me think of taking my car elsewhere whenever I have to carry out any work on the car. The problem is that I'm trapped, as they're the only BMW specialists in my town.

Always a problem with folklore, the uneducated, the botchers and then in the other direction user / garage's experience that sometimes runs contrary to the published info..

I've had to travel literally hundreds of miles to get best in class support..and even then been let down..its never easy..the problem these are complex cars and not very common so for many garages its a journey into the unknown as much as for the owner..

[TIMMOS29]

TBH I think I'd be looking for a new BMW "specialist"!

I think you're right! Actually, I must admit that when I went to my local BMW dealership and I explained that I had been to this "specialist", stating the issues, they told me "we normally have to repair the cars they can't fix or they mess up". Ouch!
But as I said in a reply to another member, lesson learnt. Even if I have to go far away, I'm going to try to find a good BMW independent specialist in the Suffolk area.

Ask on here if someone can recomend a good indy or better than that a guy that knows BMs that can help you.

[Mr Tidy]

Here's a link to a list from another forum:- https://www.pistonheads.com/gassing/top ... 2&t=796191

There is one in Suffolk, but if that is where you've been going it won't help!

Depending where you are in Suffolk there are options in Essex and Norfolk - plus of course our very own enuff_zed at the HQ of "Norfolk Zed Rescue"!

[Scooba_Steve]

It's always worth a quote, sometimes they have deals on e.g. proper air con clean for £45.

I would love to know what this 'proper air con clean' involves for £45.00.
The only things you can 'clean' on a car's a/c system are the evaporator coil and/ or the condenser coil. To 'properly' clean the evaporator coil involves a LOT of work. The entire dash needs to come out, for starters. To clean the condenser coil involves quite a bit aswell. Neither are something any car garage will a) know how to do IME and b) if they did they would be charging for 5 hours plus work and materials.

The last time I did a 'proper' clean on an car's a/c system it took nearly all day. So at dealer rates that around £2,000.00

I would guess that the 'proper air con clean' (for £45) will involve them sticking one of those anti-bacterial 'bombs' inside the car and running the a/c on recirc for half an hour. You can do that yourself for a fiver. That is far from a 'proper' clean, though.

Whatever is in TIS. Wasn't a bomb, more like a lance with expanding foam cleaner.

[Scooba_Steve]

I think you need to have something more important to worry about TBH. Fussing about which colour or 'G' number is in your car is mad.
It's coolant!

Do you ignore the spec for oil and just put anything in?

[SV8Predator]

Whatever is in TIS. Wasn't a bomb, more like a lance with expanding foam cleaner.

Expanding foam cleaner? That frightens the life out of me. How do you get that stuff out of the system?

I'm with Pond on this one I'm afraid.