Low Coolant Indicator - 97 Volvo 850

[jtgalloway]

I have a 97 Volvo 850. The low coolant light comes on. When I check the resevior, it looks empty, but when I take off the cap, the resevior fills from the tube running from the thermostat. Once the resevior is full, it slowly empties back into the system. I keep adding coolant and can't find any leaks.

Anybody ever experienced this or have any ideas?

[MilehighV70XC]

Have you done any work on the cooling system recently. Either it was not completely filled back up or you have a leak some where. Coolant doesn't just disappear. When you take the cap off, are you doing it when the car is warm and the T-stat is open or when it is cold. When you release the pressure from the system when it is warm, the coolant will flow back into the low pressure area which is the reservoir. Once the car cools down it sucks the coolant back in if the system is not full.When the cooling system is full and you remove the cap, the pressure will blow the coolant out of the reservoir with considerable force.
Check for leaks where the heater hoses attach to the block. From underneath the car, look up where the heater hoses curve to enter the firewall. Check for coolant residue. I was hunting down a coolant leak that was not dripping, I finally noticed coolant residue on the heater hoses from a leaking hose at the block.
Check your floor boards to see if the heater core is leaking. Worst case, check your oil for coolant which means a blown head gasket. Since there is no drip, probably rule out water pump. Pretty basic system, so not really anywhere else for it to leak from.

[Rocky]

Heater matrix failures can also show up when you get condensation on the windshield.
Any white steam/smoke when accelerating?
Have you checked the engine oil? Is it milky? Is your antifreeze the correct color? Looking for leaks between vital engine systems!

[baldyjones]

My 2001 v70 xc shows the low coolant indicator-I check the coolant resivoir(engine hot) and the coolant is right at the low coolant line. If I slowly release pressure in the resivoir , the coolant rises bck to the max line. The temp gauge has never gone over the half way mark. I seem to add mora cup of coolant every week or so . Is there such atheing as so much pressure in the system it forces the coolant down. Help!

[rspi]

@ JT, likely a bad head gasket. Early stages. Sell the car before it gets bad or you overheat it. Just kidding about the sell it fast part. Buy here is my link and story about our S70.

http://volvoforums.com/forum/volvo-s70- ... ems-63516/

Head Gasket Replacement

Just got finished doing a head gasket job on our turbo S70 GLT. The car had the strangest head gasket leak, one that was new to me. You can skip the story if you'd like.

A few months ago my daughter (from college) called and said that she was having coolant problems. When she started the car, the low coolant light would be on. Then she would drive and the light would go out within minutes. After about a week, she call and told me what was going on and I told her to check the reservior while the car was cold, and if it was low, add some while it was cold. So she went and picked up some coolant and needed to add some. This went on for weeks, weeks turned into months. About 5 months into this cycle she came home for the summer. Right off I didn't have a chance to check it out and a few weeks later she went on a road trip 550 miles away (same weekend I was taking one 750 miles away). So, I told her to check the level before she left and top it off, and stop every 200 miles and let it cool down and top it off. Off we went and no, she didn't top it off. 4-1/2 hours into our trip she calls me and tells me that she has stopped on the side of the road because the car started to overheat. I had always told her, if you ever see that needle going into the red, stop immediately and turn the car off. If you don't, it will overheat and destroy the motor. So, it was out of coolant and the overfill line from the res to the thermostat was split. So she added bottled water and drove to the nearest AutoZone at 45 mph. Hose replaced, coolant filled, and off she went, no more problems at all (other than the coolant getting low every few hundred miles). I believe God had mercy on us and maybe using full synthetic oil helped as well. She got back home fine and a few days later I test drove the car. Before starting cold it was at the min mark. After driving 6 miles it was at the full mark. After driving another 3 miles it was above the full mark and the res looked stressed. After another 5 miles coolant was escaping from the res cap. That's not right. So after speaking to several mechanics I came to the conslusion that there was a small breach in the head gasket. Combustion / exhaust air was getting by the head gasket, into the coolant system and forcing the coolant into the reservior and out the cap, leaving the block without coolant (if none was added regularly). There was no oil in the coolant, no coolant in the oil. My guess it that many head gasket leaks start this way and people keep driving until the block is dry and it cracks or totally blows the gasket (fluid mixing, smoke, etc.). So, I decided to replace the head gasket before she missed a refil again and destroy the motor.