My 2002 Volvo V70 XC Turbo overheated (the dash and gauges were broken so the problem showed itself when it started steaming) and had these symptoms. Coolant in the oil, coolant disappearing, and steam coming out of the exhaust pipe. I was reasonably sure it was a head gasket failure, so I started taking it apart. Today I took the head off. I did not see any major breaks. Here are some photos.



I did find a break, where the light is shining through.



The head does not have any visible cracks. The blue is where the break I found was.






Cylinder 3 looks cleaner than the rest, so coolant was getting in there.







Coolant mixed with oil





Here is a another photo of the break. It also seems there is a crack running from the hole to the cylinder.


Let me know if you need more or better photos.

It doesn't seem to be a direct path for coolant to get into the cylinder. Also, how would the oil mix with the coolant?
How would I tell if the head needs to be surfaced, or is warped?

 

You answered most of your own questions - compression is leaking into #3 cylinder through the clearly damaged area. And oil mix with the coolant? As I mentioned that is never seen with a Volvo. Possibly near cyl 5 - is that an oil drain? , so the oil would not be under pressure there -

Warped is measured using a straight edge - a 3 foot long piece of perfectly flat steel - but your head is warped. It was seriously overheated. You had no temp gauge! Is the plastic spark plug cover melted on the edges where it touches the head? You might be able to check for warpage on the top of the head after removing all the valves - remove the valves and put the cam back in - spin a cam by hand and check clearance between the cam bearing front and rear

 

I did the cam thing, and it looked good. I looked at the spark plug things, and they were not melted. I found a metal yardstick, and according to that, either the yardstick or the head is warped. I will probably get it machined. How do I tell if the head needs straightening? Is that common?

When you say " And oil mix with the coolant? As I mentioned that is never seen with a Volvo. Possibly near cyl 5 - is that an oil drain? , so the oil would not be under pressure there -" I am confused. My oil looks like light brown mud or chocolate milk. Are you saying that there is no problem with the head that caused coolant getting into the oil?

Also, can you explain what you are seeing where you circled in red?

Merry Christmas

 

warped heads don't get "straightened" but the flat surfaces can be milled to come back into spec. Best to visit a machine shop to have them measure with their professional tools and see if the head can be rebuilt or needs to be replaced.

Regarding how oil and coolant can mix, think about what's going on inside a warm, running engine. cylinders typically produce 150+ PSI when there is no combustion so that's where a failed seal by the metal head gasket rings can push exhaust gasses into the other passages for oil and coolant. Similarly, your oil pressure willl be as high as 60-80 PSI range for a running engine so if the oil passages are not sealed properly by gasket, oil will find its way into lower pressure areas. Finally you have your coolant system which will be in the -15 20 PSI range (15 PSI being ambient atmosphere) so oil pressure is like 5x that of coolant pressure. That says if the head gasket fails around an oil port, it will push oil into the coolant. Similarly, if the head gasket fails around a piston and a coolant port, it will push exhaust gasses into the coolant which in turn can add HCs to the coolant (thus the HC test kits) and can add additional pressure to the coolant system - enough to make hoses rock hard or worse - pop off the overflow cap (which is really a pressure release valve).

One other thought - when you have your head at the machine shop, you will probably want to ask them about doing a dye test on the head (ie a magnaflux test) which is used to ensure you don't have a crack in the head itself. Not sure if that's a common issue for white blocks or not.

 

I was told warped heads need to be straightened because the cams on top would not be aligned as the head warps on the top also. I put the cams in the head, spun them, and didn't notice any problems with alignment. Does this mean that I can not see the bad alignment, or it is good?

Also, as you were saying, oil is higher pressure than the coolant, so it would seem that I would get oil in my coolant. However, It is the other way around; coolant is getting into the oil for my car. How would this happen? The gasket does not have any visible cracks or breaks near the oil holes.

 

In my part of the world my machine shop straightens Volvo heads that are warped to make sure the cam journals are aligned - I would imagine using a process similar to this you tube video. Note they are trying to fix .015 - fifteen thousands of an inch.


At this point that needs to be answered before or during the head refurbishment process. Before head replacement and the same thing happens again.

I suppose it's possible - Your cooling system would have been under extreme pressure after the engine was shut off. That high pressure coolant could have leaked into the oil through the oil cooler. The oil pressure would be 0 at the point, radiator pressure maybe 25 psi if the cap did not release. As I mentioned I have only seen a few oil coolers fail the other way - 75 psi oil get into the 15 psi coolant.

 

Is there anything I can do to tell if it needs to be straightened?

Also, how would I go about finding how coolant is getting into the oil?