2008 XC90 2.4 D5 overheating issue

[Tomanuel]

Long story short: A few months ago, the car overheated on the highway. Mechanic replaced the cylinder head (it was cracked). It ran fine for a few days, but then it started overheating again, always accompanied by minor coolant loss.

The mechanic then pointed to a faulty cooling fan. I replaced it myself, but the issue persists.

Worse, I sometimes see light smoke from the engine bay and smell a strange mix of coolant and exhaust fumes.

Crucial detail: Whenever the temp needle rises, the interior heater immediately stops blowing hot air.

I’m done with that mechanic and want to DIY. I’m planning a CO2 leak test to check for a cracked block/head or EGR cooler issue. I also suspect the water pump (which wasn't replaced with the head).

Any experience with these specific symptoms? Thanks for any help!

[dikidera]

Check thermostat first. The other thing I would check is EGR, maybe exhaust gasses leak into coolant through there.

I recently repaired such an XC90 and those things take a while to get to temp.

interior heater immediately <- sounds like air, a lot of it.