Q: Hi man.. I own a 2007 VW Passat 2.0, I got check engine light showing code p2181 cooling system error. Should I change only the th

Hello. A P2181 cooling system code is really generic, and all it means is that the cooling system is too hot or too cold. Unfortunately that does not give you much to work with. Check the level of your coolant, and what the dashboard reads (which is not always accurate in low coolant level conditions). We need to start by finding out the temperature of the engine when running, and this needs to be done with a tool off of the vehicle for accuracy. There are several ways this can be done, and most automotive parts stores can test this for you. Once you know if it is too hot or too cold, you can do some further diagnostic testing, and take corrective action from there. For more help with this testing, contact our service department to schedule an appointment.