I recently purchased a 1989 300CE. I love the car so far, but I have a few questions since I acquired it.

1. When operating the HVAC I can hear a gurgling noise coming from the dashboard. It almost sound like running water from a tap or hose. It stops immediately after I press the "0" on the automatic climate control panel. Is this normal?

2. I need to get extra keys cut for the car. I took the key to the local locksmith but they told me that they couldn't cut it and that I would likely have to go to the dealer. Is this true?

3. How can I tell if my car has the factory alarm system? I checked the Russian VIN website and it says that it has the anti-theft warning system. Is there not a light or indicator that will come on to indicate that the alarm has been activated?

4. My seatbacks don't lock even while driving. How do I correct this? I understand that they are vacuum locked when the engine is running and the doors are closed. What can I check?

5. The car is difficult to start. I often require to feed it a bit of gas to get it started and keep it running. There is also a rough/uneven idle. I have ordered the factory service manual on CD as well as the Haynes manual to try and diagnose the condition. What things should I look into? I'm thinking that one or more of the injectors is not operating correctly. How can I find out which one is the culprit?