Temp drops while driving 2002 S80 T6

red057 · Post by **red057** » 27 Mar 2012, 07:18

I own a 2002 S80T6 193,000 miles on it. The radiator was leaking so I had it replaced, last night while I was driving on the highway the temp gauge dropped. The temp didn't drop all the way down but dropped to between cold and normal. When the temp dropped I felt cool air from heater.

fn42 · Post by **fn42** » 27 Mar 2012, 12:11

check coolant level - it may not have been bled correctly when the radiator was replaced

no heat usually means there's no coolant flowing through the heating system

Post by **boosted5cyl** » 27 Mar 2012, 18:53

Did the temps go back up when you stopped? Might be a stuck open thermostat.

Post by **fazool** » 27 Mar 2012, 20:02

big air pockets in the system. Started moving fluid then air. Bleed the system.

red057 · Post by **red057** » 29 Mar 2012, 07:43

Temp is normal when driving on local streets, check engine light is on.

Post by **mikealder** » 29 Mar 2012, 11:45

Change the thermostat, the check engine light will be on because the ECU isn't happy with the engine temperature reading, it also tends to turn the radiator fan on high speed all the time, you should still hear it running for a couple of minutes after shutting the engine down, if the above fits the bill get the thermostat changed as it's letting the engine over cool which is burning fuel there probably isn't anything wrong with the temp sender unit - Had this on my V70 a couple of years ago, cheap and easy fix, if DIY make sure you soak the thermostat housing bolts with release oil for a day or two before undoing the torx head bolts, also consider replacement bolts from Volvo which cost very little and make the job easier next time - Mike