The car ('88 245 B230F) was running fine this morning, came home from a 50 mile trip and noticed the exhaust was a bit louder and had a burbling tone to it. From inside the cabin and with the hood closed it doesn't sound too bad but you can tell the exhuast is not smooth, however, with the hood open it sounds like a lawn mower and the sound seems to be coming from the exhaust manifold area. I can smell the exhuast fumes in that area as well.

Is it safe to assume its the exhuast manifold ? or could it be a downpipe too ? Will a junkyard manifold from any B230F motor work ? There's a quad light (older) 240 with a B230F at the junkyard near by, the oxygen sensor on it is not the 3 wire like mine but I assume the bung for the sensor is the same size ? btw they want $52 for it, i suppose I should get a warranty on it in case its bad too ?

What tools do I need to get this off at the junkyard ? A 13mm socket and a combination wrench (for the two bolts that connect the manifold to the downpipe) ? Can I remove the O2 sensor with a combination wrench or do I need a special wrench for it ?

Thank you for your help!
Sometimes the volvos can be more fun than you can handle...