Bubbles in coolant reservoir

[noscail]

Hi! As the title says, my MK3 Focus 1litre ecoboost coolant resovoir is full of bubbles! anyone have any idea what caused this? Please see attached picture.

Cheers.

[Comares2001]

Could be head gasket. What does engine oil look like on dipstick?

[noscail]

19 minutes ago, Comares2001 said:

Could be head gasket. What does engine oil look like on dipstick?

Thanks for the reply. The oil looks normal on the dip stick, what am I looking out for?

[StephenFord]

In the olden days, if you removed the oil filler cap and it had a 'mayonnaise' type gunk in it, that was an indication of a blown head gasket. Though that was in the 70s LOL Not sure if modern cars give the same symptom!

[Comares2001]

Sometimes but not always if head gasket leaks , coolant gets into sump so oil would look milky colour. If your not losing coolant and engine is running normally I would just monitor things but a compression test on each cylinder at a garage should show if the gasket is leaking combustion gases into the coolant. If it is you may also see a change in colour of the coolant.Another possibility although unusual is that you have a faulty expansion tank cap that is allowing air to enter the tank when its cooling although I would have thought if it was this the engine may be overheating and you may also see coolant level going down.

[pragmatix]

Get a sniff test done, this will tell if it's head gasket, most garages should be able to do it.

[st line x 140 driver]

looks like someone's urinated in it😁 when was the fluid changed last looks pretty weak.- change and see if you get same symptoms.

[noscail]

I changed the coolant this morning, it seems to be fine now! Wonder what caused all of those bubbles? I'll keep an eye on it. Thanks for the replies!