Now, before you judge me for posting yet another thread regarding low coolant levels, hear me out. 2015 s60 p3 chassis 5 cyl awd. 2 weeks ago I replaced the oil filter/pcv housing. While taking out the air box, the nipple/port of the engine coolant check valve (yes its a thing) (part number 31325609) snapped off at the connection point of the coolant bleeder hose (part number 31368663). Obviously, upon doing so, coolant began dripping, and sometimes gushing, out of the broken check valve.

I have since replaced both the bleeder hose and the check valve, but this morning I went to start it and got the dreaded "engine coolant level low" message. The coolant level was just below the minimum line. If there is a leak somewhere, it is not easily spotted. I'm also having issues with my abs and traction control. Car was put into limp mode last night until i shut off the engine and restarted it. I think this is a separate issue but I figured I'd give as much info as possible. Is there a chance that there is air in the system? An internal leak? I will also say that, as of now, the ratio of water to coolant is like 80 water 20 antifreeze.. could this be part of the issue? TIA

 

Easiest method to find a coolant leak is with a radiator pressure tester - perhaps your local auto parts store has one to lend/rent. Once fixed you should try to run a 50/50 mix of antifreeze and water. Some insist it's best to use distilled water for maximum life and the least corrosion. (i wouldn't worry too much about the distilled water on a 7 year old car, but others will disagree)

Internal leak? Sure that could be from a damaged head gasket (from overheating) and the coolant is getting into the cylinders. You can test for combustion gasses with a fluid based leak detector - that the auto parts store might lend/rent and you just buy the fluid.

Abs/traction control - first step would be to scan all the control units to see if any codes are stored and if so - develop a reasonable diagnostic process.