VW Caddy Weak Heat Points to Faulty Water Valve

I had a very similar issue with my 2014 VW Golf with a 1.4 TSI engine. Based on my experience with car heating systems, the symptoms you describe match what I encountered. My car showed weak heating performance and the water valve was indeed the culprit. The workshop found that the cable connection to the valve was damaged, causing intermittent operation. The coolant flow was affected, leading to poor heat transfer to the cabin. The repair involved: Diagnostic scan to confirm error codes, Testing the water valve functionality, Replacing damaged wiring and connectors, System bleeding to prevent air pockets Total cost was 95€ for parts and labor. After the fix, cabin heating worked perfectly again and the error code cleared. A blocked valve can cause engine overheating issues too, so addressing it promptly is important. To provide more specific advice for your case, could you share: Which engine variant does your Caddy have? Are you noticing any coolant leak signs? Does the heating work better at higher engine speeds? What exact error code is stored? These details would help determine if your issue matches what I experienced or if other components need inspection.

Thanks for sharing that experience. At my latest service at 127032km, the mechanic actually checked the heating system but found no obvious issues. Yet the problem persists. To answer your questions: 1.4L TSI gasoline engine, No visible engine coolant leaks, Heating performance stays weak regardless of engine speed, Error code P0597 stored The symptoms match what you described. The constant weak heating output suggests the car valve control might indeed be the problem. Did your repair also require a full cooling system flush, or was the valve replacement sufficient on its own?

Based on those details, your case sounds nearly identical to what I experienced with my Golf. The P0597 code specifically relates to thermostat heater control circuit, which aligns with the valve control issue I had. In my case, the valve replacement alone resolved the problem, no cooling system flush was needed. However, the workshop did perform a thorough inspection of the automotive valve assembly and surrounding components while the system was open. Some key findings from my repair that might be relevant to your situation: The valve blockage was causing inconsistent coolant flow, Car heating performance remained weak even after the engine reached operating temperature, No engine overheating occurred despite the faulty valve, The system needed proper bleeding after the repair Total repair time was about 2 hours and cost 210€ including the new valve. Given your mileage and symptoms, I strongly suspect you are dealing with the same valve control malfunction I experienced. Suggest having the workshop specifically test the valve operation with their diagnostic equipment before proceeding with replacement. This will confirm whether your heating issues stem from the same root cause.

I appreciate all that detailed feedback. The situation seems really similar, especially since we have the same engine type. Given the error code and symptoms match exactly, I feel more confident about pursuing the valve replacement route. Planning to book the car in next week and will specifically request: Valve operation diagnostic testing, Inspection of valve control circuit, Professional bleeding of the cooling system after repair My only concern is whether 210€ is still a reasonable price point for this repair currently. The car valve replacement seems straightforward enough, but I know parts prices can vary significantly. At least I now have a better idea of what to expect regarding repair time and process. Going to document the repair costs and results here once completed. Really helpful to know that the poor heating output was fully resolved in your case without needing a complete cooling system flush. Hoping for equally good results with my repair.