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

Varixto · May 20, 2025

A few days ago I decided to check the coolant. The level was ok but it was hard to tell the colour, as the expansion tank is black.

I checked it and the old coolant had barely any colour, just a slight grey tint to it. I simply syringed some out and it was pretty much colourless, semi-transparent.

Today I took my car for a coolant flush to a local BMW indy.

When I picked the car up, I asked what kind of coolant had been used and the two people at the reception desk couldn't give me a specific answer, just "pink". BMW's OEM is normally blue and the spec is Glysantin G48.

I have emailed them and hopefully will be taking my car back tomorrow to have both issues rectified.

Should I be concerned? What could be the issue that has caused the whitish/very light brown oily and slimey residue?

By the way, they used a radiator cleaner product called Normfest radiator cleaner. (Normfest 2897373) but that does not explain why the residue is slimy AND oily to the touch.

This residue in the coolant tank has appeared AFTER I took the car to the workshop. It wasn't present before...
Could it be the mixing of coolants? Perhaps using a funnel or a container contaminated with oil?
Another (worse) possibility would be the oil cooler gasket failing but they would have had to drive the car really hard while with them for it to suddenly leak...having said that, there was a Google review where a customer (who had a tracker) complained about his car being driven very fast while being road tested.

I hope this is not a sign of something much more serious...

Any advice will be much appreciated!

B21 · May 20, 2025

Could be all sort of strange reactions…gold standard solution is to flush out with deionised water to get rid of contaminants for a few minutes then refill with G48 and then review

john-e89 · May 20, 2025

Your car is what, 14 odd years old, many thousands of miles on it I presume, what are you worrying about, a little slime after all that time and miles is nothing to worry about. You’ve flushed out a system that probably hasn’t ever been flushed before, you can’t expect pure water/coolant now. Quit whittling.

Varixto · May 20, 2025

john-e89 said:
Your car is what, 14 odd years old, many thousands of miles on it I presume, what are you worrying about, a little slime after all that time and miles is nothing to worry about. You’ve flushed out a system that probably hasn’t ever been flushed before, you can’t expect pure water/coolant now. Quit whittling.

The car has only 62k miles. My daily Megane 1.5 dci Mk3 with 115k mile's coolant is in perfect condition.

Scooba_Steve · May 20, 2025

john-e89 said:
Your car is what, 14 odd years old, many thousands of miles on it I presume, what are you worrying about, a little slime after all that time and miles is nothing to worry about. You’ve flushed out a system that probably hasn’t ever been flushed before, you can’t expect pure water/coolant now. Quit whittling.

Disagree. You've paid for a service to be carried out with the correct spec fluids. Cheap crap pink coolant isn't that.

Varixto said:
This residue in the coolant tank has appeared AFTER I took the car to the workshop. It wasn't present before...
Could it be the mixing of coolants? Perhaps using a funnel or a container contaminated with oil?
Another (worse) possibility would be the oil cooler gasket failing but they would have had to drive the car really hard while with them for it to suddenly leak...having said that, there was a Google review where a customer (who had a tracker) complained about his car being driven very fast while being road tested.

I hope this is not a sign of something much more serious...

Any advice will be much appreciated!

I wouldn't immediately worry, but I would want the correct coolant to be used.

Having had an oil cooler gasket fail I can't recall any visible contamination, but I did run a system flush/cleaner through before doing two plain water flushes. Easy with the electric pump to ensure it all circulates but far too time consuming for a garage.

I, personally, wouldn't be going to an alleged BMW specialist that doesn't use the correct spec fluids.

Do you have the time/ability/interest to start DIY?

My F10 had some crap pink coolant in. That was oily. You may be onto something with them possibly using the same equipment for oil/coolant. Now I use a clean 20L bucket and vac filler for coolant changes.

Varixto · May 20, 2025

B21 said:
Could be all sort of strange reactions…gold standard solution is to flush out with deionised water to get rid of contaminants for a few minutes then refill with G48 and then review

I've emailed them explaining everything. Hopefully I can take the car back tomorrow to have both issues rectified.

Mr Tidy · May 20, 2025

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

Varixto · May 20, 2025

Scooba_Steve said:
I wouldn't immediately worry, but I would want the correct coolant to be used.
Having had an oil cooler gasket fail I can't recall any visible contamination, but I did run a system flush/cleaner through before doing two plain water flushes. Easy with the electric pump to ensure it all circulates but far too time consuming for a garage.
I, personally, wouldn't be going to an alleged BMW specialist that doesn't use the correct spec fluids.
Do you have the time/ability/interest to start DIY?
My F10 had some crap pink coolant in. That was oily. You may be onto something with them possibly using the same equipment for oil/coolant. Now I use a clean 20L bucket and vac filler for coolant changes.

I emailed them because by the time I had arrive home and checked the coolant, they had just closed the workshop. In the email I explain what the issues are and that I would like the coolant replaced by the correct type and have the oil/residue in the coolant fixed. I'm giving them a ring tomorrow first thing and I hope I'll get somewhere with them... but I will definitely NOT be taking the car there again!
You're absolutely right...I was rather shocked when they told me about the pink coolant, specially as they've worked on the car before and I had been satisfied with the repairs.
In fact, they told me today upon leaving the car there woth them that the coolant is a "lifetime coolant" and that it should not need to be replaced!?
To be honest, that should have set the alarm bells ringing. The only issue is that it's the only BMW "specialist" in my town. The other option would be the local dealer and that...well, it's not an option for my wallet.

Regarding DIY, I normally do the servicing of my cars myself. It's just this time, for some reason I decided to take it to a workshop. I used to have a 225 Mk1 TT years ago and that was an absolute nightmare of a car so I had no choice but to learn how to DIY quite a few things, including fitting shocks and springs and a long etc... I do brake discs, pads, servicing, etc... and I will continue to do so, specially seeing what the local "BMW indy" is like.
I will try to get the workshop to fix these issues, since they've caused them but from here on, lesson learnt. I will try to do as much of the work as my ability allows me.

Varixto · May 21, 2025

Mr Tidy said:
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.

Varixto · May 21, 2025

B21 said:
Could be all sort of strange reactions…gold standard solution is to flush out with deionised water to get rid of contaminants for a few minutes then refill with G48 and then review

Thanks. That's a good starting point. Hopefully it is nothing serious other than the headache of having to take it back there and the time it might take them to have this fixed. I hope not to have any trouble with them, for example not accepting to rectify the issues and/or coming up with some bullc..p of an excuse.

Deepseaskateboard · May 21, 2025

Varixto said:
Mr Tidy said:

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

Click to expand...

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.

BMW can discount the work for older cars.
They often do this for me. They have been really up front and honest. This is Cotswold BMW, but all should discount work on older models.

Varixto · May 21, 2025

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.

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.

Well, I would have thought that if they repeated the procedure enough times, that would not have been a problem but as I have never used a coolant flush fluid before, I will give him the benefit of the doubt.

He told me that over the next week or so, as the car gets driven, some more stuff might come out of the expansion tank. He suggested either to syringe it out and top up with clean one or do what I did and use a kitchen towel sheet, dipping it and using as a "filter" to catch the residue (like I did in one of the pics).

I will pick it up in the afternoon today, hopefully sorted.

Rockhopper · May 21, 2025

I've never heard of a coolant flush product before - sounds like a good way to encourage leaks to be honest! I think I'd only use it after a head gasket failure when you might have oil in there somewhere.

Varixto · May 21, 2025

Rockhopper said:
I've never heard of a coolant flush product before - sounds like a good way to encourage leaks to be honest! I think I'd only use it after a head gasket failure when you might have oil in there somewhere.

I think it's mainly to flush the radiator.

Scooba_Steve · May 21, 2025

Rockhopper said:
I've never heard of a coolant flush product before - sounds like a good way to encourage leaks to be honest! I think I'd only use it after a head gasket failure when you might have oil in there somewhere.

That was why I used it, well oil cooler gasket so there could have been contamination. I certainly wouldn't advise using a cleaner or flush if the car has had even semi-regular (double interval) changes with the correct coolant.

Scooba_Steve · May 21, 2025

Varixto said:
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...

Varixto said:
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.

Varixto said:
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 · May 21, 2025

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.

What do you guys think?

Scooba_Steve · May 21, 2025

Varixto said:
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 · May 21, 2025

Scooba_Steve said:
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 · May 21, 2025

Varixto said:
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.

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

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