Hi i have a 1999 Volvo s80 and I'm having a problem with it overheating. The fan works and i removed the thermostat but still it overheats and the water boils over the overflow tank. Any ideas what this could be, I'm guessing the water pump but the water seems to be flowing when i grab the hoses. I also don't think it is a blown head gasket because there is no water in the oil but there is some coming from the exhaust. But i believe that's just from florida's humidity. Any help or ideas would be appreciated. thank you

 

Any help please? I just put a new thermostat in and still the same thing happens. I drove it with the heat on and windows open and everything was fine, which now leads me to think that the radiator is clogged. Could this be possible? The previous owner had water in it, so I believe rust just built up.

 

Replace the expansion tank cap, cheap enough and means you can isolate that to begin with. The rad could be clogged either internally or on the fins, but if the expansion cap releases pressure early (before 15PSI) the coolant will boil sooner than normal possibly leading to overheating. With an alum block and head, theres not a whole lot that can rust!

 

Just got the new cap and it works! Thank you so much for your help, I can finally drive the Volvo with no worries that something major is wrong with it.

 

Awesome, thanks for posting back. Enjoy!

 

thanks to bro I don't have the problem but if I do at least I can get the answer thanks bro

 

Hey guys, I got a 99 S80 that over heats after a short period of time on the road. I changed the expansion cap and replace the front engine seals. I'm in the process of changing out ALL the seals (rear, timing, camshaft and even valve stem). the thermostat seems to be ok but I'm replacing that today. if it still over heats, what could possibly be the issue?