Radiator fluid topup tank filled with pinkish strabery like fluid

[AinurC5X7]

Hi,

Sent my perfectly running Citroen C5 X7 1.6 THP for regular oil change, but sadly, the radiator coolant topup container is filled with pinkish strawbery like liquid. I suspect that the transmission fluid somehow is mixing with the radiator fluid.

I don't know how this could be possible. Does the car have a transmission fluid line that goes into the radiator? My mech doesn't think so.

I'm screwed big time! Help!

[GiveMeABreak]

You'll need tp provide your VIN so I can check the cooling system and type of Auto box you have.

[AinurC5X7]

It's VF7**************[VIN obfuscated, can be read by forum staff]

[GiveMeABreak]

Ok, so you have the 6 speed AM6 gearbox.

There is a cooler for the Auto gearbox that uses the engine coolant. Usually if this leaks, you will end up with some sort of goo or 'mayonnaise' in the expansion tank.

See this thread for what I mean:

viewtopic.php?p=625376#p625376

[xantia_v6]

Has the coolant been changed for OAT type with pink dye?

The transmission coolers do occasionally fail, but transfer is usually in the other direction, with water getting into the transmission, rapidly destroying it.

It would probably be best to drain and refill the transmission. If the fluid coming out is red, brown or even black the cooler is ok, if it is . mayonnaise, then the cooler has failed, but my not yet have caused damage.

[AinurC5X7]

Ok, so you have the 6 speed AM6 gearbox.

There is a cooler for the Auto gearbox that uses the engine coolant. Usually if this leaks, you will end up with some sort of goo or 'mayonnaise' in the expansion tank.

See this thread for what I mean:

viewtopic.php?p=625376#p625376

Thanks very much for the thread.

[AinurC5X7]

Has the coolant been changed for OAT type with pink dye?

The transmission coolers do occasionally fail, but transfer is usually in the other direction, with water getting into the transmission, rapidly destroying it.

It would probably be best to drain and refill the transmission. If the fluid coming out is red, brown or even black the cooler is ok, if it is . mayonnaise, then the cooler has failed, but my not yet have caused damage.

The fluid in the refill tank is pink mayonnaise. Suppose the cooler is the problem. I'm praying that none of the coolant has entered the gearbox. Cry!

[Paul-R]

Yes but what was the colour of the coolant before you had these problems?

[AinurC5X7]

I think the colour wasnt pink. I had it actually sent last to the dealers for some recall fix, and servicing too. I don't think they changed the coolant. Looked clear to me.

[AinurC5X7]

On hindsight, I wonder if putting K Seal. Into the coolant caused all this. I think K seal has some copper and you know copper reacts with aluminium. Though the bottle and website did state that it was compatible with aluminium radiators. I think the oil cooler for the transmission is made from aluminium. Perhaps the copper reacted with the aluminium to cause galvanic corrosion, then perhaps failure of the cooler.