VW Polo Cooling System Fault Causes Engine Issues

I had a very similar issue with my 2003 VW Golf TDI. As someone with some hands-on experience working on VW diesels, I initially thought it was related to the radiator grille or engine cooling system being compromised. After checking the radiator blockage myself, I took it to my regular workshop. The issue turned out to be much simpler, a blown fuse that was causing erratic temperature gauge readings and affecting the engine thermal management system. The faulty fuse was interfering with the temperature sensors readings, leading to inconsistent warm-up times. The total repair cost was 52€, which included diagnostics and fuse replacement. The check engine light cleared up immediately after the fix, and the engine started warming up normally again. However, to provide more specific guidance for your case, could you share: Has the coolant level been checked recently? Are you noticing any unusual sounds from the engine bay? What are the exact temperature readings you are seeing? Does the engine cooling fan activate at all? These details would help determine if your issue is similar to what I experienced or if there might be other underlying problems with your cooling system.

After latest service (115646km), mechanic traced issues to faulty thermostat and clogged cooling system passages. Temperature sensor readings now show normal but engine still runs cooler than optimal. Replaced thermostat (180€) but cooling system still needs complete flush to remove buildup affecting thermal management. Workshop quoted additional 250€ for power flush and coolant replacement. The radiator grille looks fine but internal cooling passages need attention. Would appreciate feedback from others who had complete cooling system service, did it solve similar symptoms?

Thanks for the update on your Polo. My Golf had very similar symptoms after I replaced the thermostat. While the temperature readings stabilized, the engine still ran cooler than normal, just like yours. I eventually went ahead with the power flush service since restricted airflow and clogged cooling passages can seriously impact engine thermal management. The buildup was worse than expected, the flush removed a significant amount of deposits that were affecting coolant circulation. The complete service cost me 285€, but it was worth it. After the flush: Engine reached proper operating temperature normally, Temperature gauge readings remained consistent, Heater performance improved significantly, Engine overheating concerns were eliminated One tip: Make sure they use the correct coolant specification after the flush. Using the wrong type can lead to new deposits forming in the cooling system. The workshop should use G13 for your VW. The price you were quoted seems reasonable considering the work involved. Based on my experience, I would recommend proceeding with the complete flush to restore proper cooling system function and prevent potential engine overheating issues down the line.

I appreciate the detailed feedback about your Golf experience. Good to hear the power flush resolved similar issues, it matches what my mechanic suspected about deposit buildup affecting the automotive cooling performance. Just scheduled the cooling system flush for next week. The 250€ quote seems fair compared to your costs, especially since it includes the proper G13 coolant. The workshop also mentioned they'll pressure test the entire system afterward to ensure there are no leaks or restrictions remaining in the cooling passages. Makes sense about the deposits potentially causing my current symptoms. Once the engine cooling system is properly cleaned, hoping to see the same improvements you did with consistent temperature readings and better overall thermal management. Will update here after the service to confirm if it fully resolved the cold-running issue. Thanks for sharing the specific results you got after the complete flush. It helps validate that I'm likely on the right track with this repair approach versus continuing to chase other potential causes.