So I was topping up my coolant the other day and noticed a faint, sweet smell coming from the engine bay after I drove it. The level in the overflow tank doesn’t seem to be dropping, and there’s no visible leak on the garage floor, but that smell has me a bit worried. Has anyone else had this happen without any obvious signs of a problem?
That sweet coolant aroma after topping up would set off alarms for me too even if the level looks steady.
Sweet smell can come from a small vented leak or a tiny crack in a hose or reservoir cap that only leaks under pressure.
I am wary of assuming a problem just because you smell something Even if the level stays constant and no wet spots show up maybe it was just stray coolant vapor.
Maybe the framing should shift to whether the odor is persistent or just a one off after a fill which points to how we monitor coolant health
Try a simple pressure test on the cooling system to see if there is hidden seepage Clean the area and watch for damp spots after a drive
Old coolant can break down and lose its scent as it ages If the car has many miles check the coolant age