Mercedes CLK Diesel rough cold starts and PTC heater issue

I had a similar issue on my CLK Rough running on cold starts and the HVAC system wasn't kicking out any heat It sounds like your blower motor is working, so it's probably not that Have you noticed if it gets better after the engine warms up a bit Do you have any way to test the PTC heater or check its wiring

Yes, the engine runs much better after it warms up I don't have the equipment to test the heater directly Where is the heater located Is it difficult to access for inspection

From what you're describing, it really does sound like the PTC heater It's there to give you instant heat until the engine warms up It's buried pretty deep in the dash, near the main heating system components Honestly, getting to it is a pain without the right tools and knowledge I'd suggest taking it to a workshop for heater repair It cost me around 350€ to get mine fixed

Thank you for confirming my suspicions and providing the cost estimate I'll take it to a trusted workshop for a proper diagnosis and heater repair At least I have an idea of what to expect now