Coolant pressure
 

I had a coolant hose from a coolant pipe to the turbo split. It had a bulge by the hose clamp. I replaced the hose, then when I was driving the car about a mile down the road, the hose from the thermostat to the radiator came off. That hose looks older and is showing some cracks but not split yet. Is it normal to build up that much pressure to blow the hose off? Also, I noticed when the car sits idle for a few minutes, the temperature gage rises to just under the red lines. Is that normal? What would cause that?

Definitely not normal. The only coolant line that I know of to the turbo is a steel line. There is a soft hose that runs from the reservoir to the coolant gateway piping on the back of the engine. Maybe that's the hose that originally failed?

Let's see a few pics of what is happening.

Pics
 

Here is a picture of the rubber hose that split at that hose clamp. The hose goes to one of the 2 nipples on item number 7 of the coolant diagram. I fixed that, then the hose from the thermostat to radiator; item 12 in cooling diagram, blew off after driving 2 miles down the road.

I have never had a volvo before, so I am not sure how everything is connected. I think the engine sounds okay, but I am not sure what sounds I am expecting. I would think I could hear the turbo more, maybe...

The hoses on item #7 are heater hoses, at least one.

Hose #12 is the upper radiator coolant hose. If you're blowing them off you either have excessive pressure or the clamps are not tight. From what you are describing, it appears to be a head gasket leak.

Pressure
 

I was talking with a friend and he said that if there is not enough water in the system, it could build up pressure and do that. I am not sure about that, but seems plausible.
I do not see much of any water leaking now that I replaced the one hose and the upper hose did not come off yesterday when I was idling the car for a bit.
I did however start to see some oil leaking to the ground. I was laying under the car and it appears to be from the drivers side of the engine. I can not see where from though.
Pretty good leak. Could water be getting into the engine and pushing oil out from somewhere? It seems like the leak is below the air box on that side. At first I thought it was from the
transmission seal where the axle come out but it looks to be above the hose that I replaced. Any suggestions?

The system is relieved by the radiator cap, and they run under pressure all the time, but the relief pressure is modest. The temperature indicated by the gauge sounds bad. Volvos don't like that. Every one I have had, the temperature runs right at 3 o'clock, middle of the range, all the time.

As far as water getting into the engine and pushing oil out, that is possible, but your water level and oil dipstick would show you that was going on. It takes a lot of water to do that. I don't think that is your problem. I would look at the rear (driver's side) exhaust cam seal first if I had a big oil leak that I thought came from the drive axle.

Usually the temp stays in the 3 o'clock area.

I think the water problem is fixed, no leaks that I see. Now I have the oil leak... where is the rear exhaust cam seal located at? Trying to find it in the Volvo parts diagrams on
https://usparts.volvocars.com/volvo_...70/engine.html

Is there a good place to get a Haynes or Chiltons manual? Or an digital copy of a manual?