The temperature gauge for my Volvo 740 shot up on my way to school today, the needle shot up past the red part of the thermometer and stayed tbere.

 

that could mean either the sensor has failed, or you are in fact overheating, typically due to loss of coolant or broken water pump belt. if you were overheating, your engine block would smell burnt if you'd popped the hood, and you should NOT have driven any farther than to the nearest place you can get safely off the road.

are the belts intact? coolant level OK?

 

If not the belt or lack of coolant or not enough antifreeze then I would consider a stuck thermostat.

 

Okay, thanks everyone, it seems that I have a blown headgasket. Is there any way I find some resources to get it done myself?

 

head gasket is fairly straight forward. remove the valve cover, remove the timing belt and cam shaft, remove the intake manifold, detach the exhaust downpipe from the exhaust manifold, remove the head (leaving the exhaust manifold attached as its a bear to get off). take head to machine shop to be surface ground and tested (typically ~ 150-200$). use genuine head gasket, new head bolts recommended, reassemble in reverse of assembly order. there's a specific pattern and method to properly torque the head bolts down, you should be able to find this in the bentley 240 book. use new intake manifold gasket, use new valve cover gasket, new timing belt. use new exhaust downpipe gasket too.

most folks go ahead and replace the water pump since its all apart unless you know your pump was new in the last 60K miles or so.

 

Is there any place where I can get instructions for this, perhaps an online manual or something?

 

Volvotips.com is a good start for an online manual. Also try googling something like "volvo 240 haynes PDF" or "volvo 240 service manual pdf"

 

also here, https://www.volvoclub.org.uk/faq/Hea...sketRepair.htm
and https://www.volvoclub.org.uk/faq/Eng...eplacementTips