VW Eos Coolant Mystery: Stop That Recurring Leak

Last year I worked on a similar issue with my 2011 VW Scirocco 1.4T. The symptoms matched exactly, recurring coolant warnings despite no visible leaks around radiator hoses or connections. The root cause turned out to be air pockets forming in the cooling system due to a failing water pump. The plastic impeller inside had started deteriorating, causing inconsistent coolant circulation. The cooling fan was cycling more frequently than normal to compensate. Key diagnostic signs that pointed to this: Coolant level dropping slowly without visible external leaks, Temperature gauge showing slightly elevated readings, Sweet smell from engine bay after longer drives The repair required: Complete water pump replacement, Bleeding the cooling system thoroughly, Pressure testing all radiator fluid connections, Replacing worn radiator hoses as preventive measure This was classified as a serious issue since continued operation could have led to engine overheating. The plastic impeller design is a known weak point in these engines, typically failing between 90000-120000km. For diagnosis, ensure the shop performs a proper pressure test of the entire cooling system and inspects the water pump operation specifically.

Thanks for sharing your experience. That sounds exactly like what I am dealing with. Had the same smell and temperature behavior you described before taking it to the shop. Did you remember roughly how much the complete repair ended up costing? Also wondering if you have experienced any coolant issues since replacing the water pump and if the coolant reservoir has stayed at the proper level. My local shop wants 800€ for the full job including new hoses, but I am trying to figure out if that is reasonable. The head gasket thankfully seems fine based on their testing, but they mentioned the radiator cap should probably be replaced too while they are at it.

Good news, my coolant issues were fully resolved after getting it properly diagnosed and fixed. The cable connection to the cooling system sensors was damaged, causing false coolant level warnings. Total repair cost was 95€, much less than initially feared. This was way better than the potential water pump replacement we first discussed. Since fixing the faulty sensor connection, my coolant reservoir has maintained the correct level with no more warning lights or engine overheating concerns. Your quote of 800€ for the full job including hoses sounds reasonable if you actually need the water pump replaced. These jobs require quite a bit of labor since they need to fully drain and properly bleed the system to prevent air pockets. The radiator cap replacement is a smart preventive measure while they have everything apart. Good that your head gasket tested fine, that would have made things much more expensive. Just make sure they pressure test everything after repairs to confirm there are no coolant leaks in the system.

Going back to the shop today was definitely the right call. After reading about similar cases, I specifically asked them to check the water pump and they confirmed it was indeed failing, exactly like described in the previous replies. The total repair came to 780€ which included: New water pump installation, Fresh radiator fluid, Replacement of two worn radiator hoses, New radiator cap, Full system pressure test and bleeding The mechanic showed me the old pump and I could see the plastic impeller was starting to break down. They found some air pockets while bleeding the system which explained the inconsistent coolant levels. After a week of driving, no more warning lights or coolant issues. The temperature gauge stays steady now and that sweet smell is completely gone. The coolant reservoir level has remained constant at the proper mark. Really glad I caught this before it led to serious overheating problems. The repair cost was worth it for the peace of mind, knowing everything in the cooling system is now working correctly.