I should have known better, since for years i have been working on engines, and presently have 2 cars under restoration.

The car has overheated in dangerous section of the highway, and i just had to top off yellow coolant with green concentrate. Now i have a cheese cake foam coming out of the reservoir. Its greasy and has light oily substance that separates.

Is it due to explosive mix i just created, or am i looking at gas/oil coming from blown head gasket?
thank for input

 

Blown head gasket. Mixing the orange and green fluid just makes a color between the two and doesn't protect as well.

 

thanx for hint. So the days of my car are counted. too bad i just did $100 "pass" inspection and today is my birthday. i better hurry with this project it is a air cooled so no more fluid color confusions

 

I will perform better inspection and compression check later, could the oil mix with coolant in the faulty radiator. foam is light in color- it probably mixes with fuel not oil, but still i just want to make sure before i ditch the car

 

I scrolled down after the initial post and got VERY confused. If you somehow filled that VW with coolant, you're either a miracle worker or very confused.
Then I read your other comment!

I'm no expert, but that's either a VW Beetle or the wierdest customizing
job I've ever seen on a Volvo.

BTW, I think the comment about the head gasket is correct. The problem arose even before you mixed the two colors of coolant. How's the oil look?
What's coming out of the tailpipe? How's you compression?

 

....Sorry for confusion.
Main question here was aimed towards volvo that i own.
Pictures below show my second car-air cooled vw beetle, which is under construction, but i will have to finish it quicker (since most likely volvo's head gasket is blown).
I hope that it explains the confusion.

Going back to original topic. In the Volvo's coolant color was yellow. After running low on coolant I have added green color coolant concentrate (not 50/50). It was due to emergency situation, i was stranded on the highway, and the bottle of the antifreeze that i've had in the trunk had a green coolant inside.
When i finally i got home, and opened a reservoir and saw bunch of white greasy foam coming out. At that point i have added distilled water, but still a lot of light foam kept coming out. I have not checked compression, or the color of the engine oil yet, but i believe that the reason for is a gasoline mixined with coolant, and is mostly caused by leaking head gasket.
For a moment i hoped that mixing two colors of antifreeze might be the reason, but i guess it is not.
I hope it helps a bit more. English is my second lanquage, and i know sometimes i write in a confusing way.
Thanks anyways. B

 

There is no way gasoline and coolant mixed unless you have a bad headgasket, then the piston bored filled with gasoline and it all escaped through a hole between the bore and a coolant galley. Check your oil, instead of doing a compression check you can just pull your plugs and turn the engine over see if water comes out one of the plug holes. Or Start the car and if steam comes out thats a positive sign your head gasket is done for.

 

I am assuming your Volvo is some sort of B23 engine. If so, replacing a head gasket on these engines is a lazy four to six hour job for someone such as yourself who seems to be fairly mechanically inclined. You'd be wise to send the head out for a quick skim too.
I say repair it.

Regards, Andrew.