Quote:
Originally Posted by raleigh753
So far I have replaced the coolant cap for a brand new one and also done the test for combustion gasses in the coolant which was negative . I have found when my other half uses it to go to work 3 miles each way after a few days the low coolant warning comes on and when checking it is at or below the minimum mark. However If I leave it alone after checking and drive a bit at 50-60 mph speeds the warning goes away and on rechecking the coolant level is normal and correct ? A bit stumped on this one ! Seriously thinking of getting rid of the car  |
On short runs, the engine might not reach operating temperature and the coolant won't expand. On your longer runs at higher speeds, the engine will get warmer and the coolant will expand to fill the expansion tank. That might explain the fact the low coolant warning doesn't activate on longer/faster journeys.
I've had cooling systems that leak when not under pressure, but don't leak when the system is pressurised. A joint that relies on an O-ring seal can behave this way, for example.
When I acquired my D5 XC70, the 'low coolant' warning was a frequent problem. For a couple of years I kept a container of coolant in the boot and topped the tank up as necessary. In spite of looking hard, I couldn't find the leak. Earlier this year I had a new air conditioning condenser fitted, and the engineer noticed a very slight weep on one side of the radiator where the plastic tank is joined to the core. A new rad was fitted and low coolant problem is now solved.
I hope this info might help you. A shame to sell your car for what is probably quite a trivial problem.