I have a 2021 Subaru Outback that suddenly pops up with eyesight disabled check manuals. I started smelling Coolant when driving but didn’t really take notes because I haven’t seen any leaking. After driving around I noticed the smell getting worse so it draw my attention to observe the temperature gage and by my surprise the temperature gage sits on dead cold but engine is extremely hot and the fans constantly run alongside the constant smell of Coolant. Check the top radiator hose and it’s very hot, while the bottom radiator hose that leads to the thermostat were much cooler. My guess it’s the thermostat. Will be pop one in tomorrow and update this after.
I did a quick parts search and it looks like the thermostat is up top from the schematic.
A common cause of hot top/cool bottom is air in the system. If you’ve been smelling coolant, it’s more than likely a leak dripping onto the exhaust manifold.
Could be a hose, like a loose fitting to the reservoir. Could be the water pump. Could be the plug you install block heaters in (less than not likely). Could be the plastics on the radiator were rattle-cracked or you took a road debris hit that put a pinhole in your radiator.
Worst: could be a head gasket.
If you’re smelling it, coolant is somewhere it shouldn’t be.
Have you done any work to your throttle body lately? I’ve personally gotten a bad seal on those hoses after pulling it for a cleaning just by trying to move fast before the sun set. It could be coming from somewhere that benign.
The smell and cool lower hose combined with no temp showing on the gauge (coolant level isn’t high enough in the block for it to come into contact with the sensor… or it could also be a bad sensor…) tells me it’s a leak… and it may have been going on for a while and caused some damage.
How many miles?
Have you added anything to your cooling system? Have you used a non-Subaru brand of coolant. Different coolants don’t always play well together regardless what the bottle says, so you could have a sludge fest going on that’s restricted or clogged circulation.
Good luck on this one and I hope it works out easily with no damage.
