97 850 GLT Overheating, losing coolant

Holly Mia · Post by **Holly Mia** » 12 Feb 2014, 19:30

Hi there.
I recently moved to America and bought a 97 850 GLT Volvo to travel the country in for a few months. Two weeks in the engine wildly overheated (according to the gauge), just after hitting the top edge of Nevada. We refilled with water, she ran okay, then overheated again, filled her up with coolant. She worked well for awhile, then continued to overheat and suck coolant. No exterior leaking. We drove through to Las Vegas, where we left her to cool down for a few days.
We left Vegas, and she was still over heating, despite refilling with coolant. We got into a garage, where they replaced the temperature gauge. Still overheated. At this point the garage believed that there was air trapped in the cooling system, so replaced the coolant container. Drained radiator system and refilled with coolant mix.
She drove well for awhile, then continued to overheat. The temperature gauge however fluctuates rapidly, which makes me wonder how true the reading is. She will drive fine for a hour or so, then the gauge will race up to almost redline, then over a few minutes slide back down to halfway. She is definitely overheating though, and guzzling coolant. At this point we are refilling coolant every half day / day: in the morning once she's cooled down from the previous night, and again late afternoon, after letting her cool down for a few hours. As I said before there is no exterior leakage of coolant, and we changed the oil after replacing temperature sensor and coolant container - there was no sign of coolant in the oil. Other symptoms - shuddering very occasionally while slowing down to stop eg, at lights - mostly only after a very long drive. Had a small oil leak under car from overnight stay, this was after the oil change however and haven't noticed any since.
Any help at all with what the problem could be would be greatly appreciated - she is our home, transport, shelter and trip out of here.
Thanks from New Zealand!

Post by **rspi** » 12 Feb 2014, 19:36

Hi and welcome to the site.

Has anyone replaced the thermostat? That is usually the primary cause of any car overheating.

Also, were are you? If you are close to me, I will help you.

Robert

Post by **cn90** » 12 Feb 2014, 19:39

1+,

Replace the thermostat.

Another source of coolant loss is the turbo coolant hoses. I understand that you say there is no external coolant leak, but during driving, some of the coolant may be blown away w/o you knowing it.

Holly Mia · Post by **Holly Mia** » 13 Feb 2014, 12:10

My mistake, when I said the temperature gauge was replaced, what I mean was the thermostat was replaced.

Post by **jblackburn** » 13 Feb 2014, 12:59

Run a compression test on a hot motor. Overheating may have warped the head gasket and one/two of the cylinders is chugging coolant.

In the future, if you ever see the temp gauge raise up, lower the windows and blast the heater on full hot.

Post by **rspi** » 13 Feb 2014, 21:39

Also, drive at 45 mph. From what I have experienced, 45 mph seems to be the magic number for having the car run as cool as possible. These white block cars will do best at 45 mph. I once drove a 960 about 25 miles with no water pump (the impeller was broken off). It did NOT overheat and after I replaced the pump everything was fine.