VW Polo's Mysterious Coolant Loss & Engine Light Drama

The symptoms you describe match what happened with my 2003 VW Golf TDI. The check engine light combined with coolant loss pointed to a failing water pump and damaged radiator hoses. Upon inspection, the garage found hairline cracks in the coolant reservoir and deteriorating radiator hoses that were causing slow leaks. The engine overheating warning started appearing intermittently before the full diagnosis. The root cause was a combination of age-related wear on the cooling system components and a water pump that had exceeded its service life. This is a common issue on these engines after 80000-90000km. This required replacing: Water pump assembly, Main radiator hoses, Coolant reservoir, Full coolant system flush The repair was quite extensive since multiple cooling system components had failed. Driving with low coolant levels risks serious engine damage, so addressing this promptly is important. Regular cooling system maintenance could have caught some of these issues earlier. Recommend having the entire cooling system inspected, not just checking for visible leaks.

Thanks for sharing your experience with the Golf TDI cooling system problems. My Polo had very similar symptoms last summer. The mechanic found air pockets in the system and a failing water pump that was causing coolant to leak. The cooling fan also had to be replaced since it wasnt kicking in properly. Would you mind sharing what the total repair cost was for your car? Just curious how it compares. Also wondering if youve had any other cooling-related problems since getting it fixed?

After my last visit to the mechanic, the coolant level issue was fully resolved. The main problem turned out to be much simpler than initially feared, just a faulty cable connection to the cooling system sensors. No need for extensive repairs like my previous water pump replacement. The total came to 95€ for fixing the cable connection, which was causing incorrect readings and making the system run inefficiently. Looking back, those air pockets and cooling fan problems from your previous repair sound much more complex than what I dealt with this time. Since getting the wiring sorted, the coolant level has stayed steady with no more warning lights. The radiator fluid circulation is working perfectly now. This repair was definitely less expensive than the full cooling system overhaul many of us end up needing on these older VWs. Just keep monitoring your coolant levels regularly, even small drops can indicate developing issues with radiator hoses or the head gasket. A properly functioning cooling system is crucial for engine longevity.

This time I went back to my mechanic after our previous discussion. The diagnosis revealed a cracked radiator cap and a small leak in one of the main radiator hoses. Thankfully, it wasnt as serious as the earlier water pump failure. The repair was straightforward, they replaced both the radiator cap and the problematic hose, then did a complete coolant system flush to remove any remaining air pockets. Total cost came to 180€, which felt reasonable considering the work done. The mechanic also showed me the old parts. The radiator cap had visible wear around the seal, explaining why the coolant reservoir was losing pressure. Since the repair last week, the coolant level has stayed consistent and the check engine light hasnt returned. Much better outcome than last time when I needed that major cooling system overhaul. Going to keep a closer eye on the coolant levels from now on and hopefully catch any issues before they become serious problems.