VW Lupo Engine Temperature Issues, Cooling Flow Problem

Having owned a VW Polo 2003 with similar thermal management issues, I can share some relevant experience from working on VW cooling systems. The symptoms you describe actually match what I encountered. Initially I also thought it was a cooling grille blockage, but after inspection at my trusted workshop, it turned out to be a blown fuse that controls the temperature sensor circuit. This caused erratic temperature readings and delayed warm-up times. The repair was straightforward, replacing the faulty fuse restored proper function to the cooling system sensors and fixed the check engine light. Total cost was 52€ including diagnostic time. Before jumping to conclusions about radiator or grille issues, I would recommend checking: 1. All fuses related to the cooling system 2. Temperature sensor connections 3. Coolant level and condition 4. Visual inspection of the cooling grille for obvious blockages To provide more specific guidance for your car overheating situation, could you share: Current mileage, When was the last coolant change, Are there any visible leaks, Does the temperature fluctuate or just read consistently low, Any unusual noises from the engine bay These details would help determine if your issue matches what I experienced or points to a different root cause in the automotive cooling system.

Thanks for sharing those details. Just had my last service at 111700km and can confirm similar symptoms, but my issue ended up being the thermostat, not the fuses. The cooling grille and radiator appeared clean on inspection, with normal airflow. A diagnostic scan revealed the thermostat was stuck open, preventing proper engine warm-up and causing the erratic temperature readings. The repair cost was 180€ including parts and labor. The thermal management system works perfectly now, quick warm-up and stable readings. Might be worth checking your thermostat rather than focusing on restricted airflow components. Looking at your symptoms, they sound nearly identical to what I experienced. Have you noticed if the temperature stays consistently low or fluctuates?

Thanks for the update on your thermostat repair. Actually, after reading your experience, I had my thermostat checked and you were spot on, mine was also stuck open. The thermal management system had similar symptoms to yours, with consistently low temperature readings rather than fluctuations. The repair cost at my workshop was slightly higher at 210€, but it completely resolved the issues. The engine now warms up normally and maintains proper operating temperature. I should have considered the thermostat earlier instead of focusing so much on potential cooling grille restrictions or radiator blockage problems. For anyone following this thread with similar car overheating symptoms: while blocked cooling system components can cause temperature issues, a faulty thermostat is often overlooked as the root cause. The diagnostic steps shared earlier are still valid, but definitely add thermostat testing to the checklist when investigating temperature-related problems. Would be interested to hear if your coolant level has remained stable since the thermostat replacement? Mine needed a small top-up about a week after the repair as the system adjusted.

Thanks for asking about the coolant level. After the thermostat repair, my cooling system has maintained proper levels without any issues. No top-ups needed so far. This whole experience taught me not to immediately assume the problem was a blocked cooling grille or restricted radiator. The proper diagnostic approach, starting with the thermostat, saved time and prevented unnecessary repairs to other engine cooling components. What seemed like a complex automotive cooling system issue turned out to be a relatively straightforward thermostat replacement. The 180€ repair cost was definitely worth it for restored proper engine operation and accurate temperature readings. For others with similar symptoms: while checking the cooling grille and radiator for blockages is important, don't overlook the thermostat as a potential culprit when dealing with slow warm-up times and inconsistent temperature gauge readings.