I have a 98 volvo S70, and am having a strange problem, in this heat the low coolant light will come on, so I would add coolant and all is good, if I add antifreeze in two to three days it is on again, straight water and it goes a week or so, car doesn’t overheat and no apparent leaks, can you help
Check your oil. Does it look like normal oil or a chocolate milkshake? Have you looked for unusual exhaust?
How much coolant are you adding each time?
also look around your radiator cap to be sure there aren’t any white, sort of chalky deposits. It’s possible that your cap isn’t tight enough.
Bring it to your mechanic and have him find out where it’s going. Most of the possibilities are bad, but if you ignore it you could do more damage to the engine.
It may be leaking into the combustion chambers and getting burned, smell your exhaust, is there a white cloud? It may be forced into your oil passage and ending up in the oil pan. If you’re lucky, it’s only a radiator cap, radiator, or water pump problem.
As you know, anything like this will be particularly expensive on a Volvo.