[phiber]

Sometimes before summer I noticed that the engine in my i30 takes a bit longer to warm up.
Called my mechanic and asked him to replace the thermostat, which he did.
Now with the colder weather it's even more noticable as it takes 10 mins of driving to get a normal temperature inside the cabin.

What else could it be besides the thermostat? Any other things to check?

For what it's worth - I don't pre-warm the engine before driving.

It's a 2009, 1.6HP iThink+ (Croatia)

[Asterix]

Does the engine reach operating temp in normal time..?  If engine becomes warm like it should the problem could be inside the cabin where the warm air isn't routed correct. When you adjust the hot/cold from your dials the air is either routed around the cabin heater or besides it. I think an electric motor does that.

If the engine doesn't get hot and you already have the thermostat replaced, I'm not sure what next step would be. If the radiator is blocked or the waterpump not working, I believe the engine would run warm...

[phiber]

The engine reaches operating temp. NOT in normal time.

The cabin and A/C work correctly.

[Shambles]

What's the water like in the expansion tank? Murky? Chewy?

I'd go for an easy start - change the coolant and see what it's like. Might need a full flush if the water looks suspect.

[phiber]

Will check it in an hour or two. I've topped it up with distilled water

[xiziz]

Mines been about 10 minutes all the time I had it, on really cold days(-20c) it takes even longer. I wouldn't worry to much about it.

It takes a long time even with the engine pre heater on for an hour prior to departure(thanks to the aux cabin heat fan, at least the cabin is warm!).

I guess its the bane of an efficient engine - not a lot of waste heat.

[Phil №❶]

It will depend on the type of driving you do. Suburban driving at city speeds on flat ground or driving down hill initially won't help to heat the engine. A nice hill & freeways enable quick heating due to the amount of fuel required to drive at increased speeds.

[Asterix]

Mines been about 10 minutes all the time I had it, on really cold days(-20c) it takes even longer. I wouldn't worry to much about it.

It takes a long time even with the engine pre heater on for an hour prior to departure(thanks to the aux cabin heat fan, at least the cabin is warm!).

I guess its the bane of an efficient engine - not a lot of waste heat.

Your's a diesel, lonypny's a petrol engine. They get to operating temperature much quicker than diesel. My i30 diesel also need 10 min driving before it's warm the wife's i10 petrol only takes half the time... 

[xiziz]

Mines been about 10 minutes all the time I had it, on really cold days(-20c) it takes even longer. I wouldn't worry to much about it.

It takes a long time even with the engine pre heater on for an hour prior to departure(thanks to the aux cabin heat fan, at least the cabin is warm!).

I guess its the bane of an efficient engine - not a lot of waste heat.

Your's a diesel, lonypny's a petrol engine. They get to operating temperature much quicker than diesel. My i30 diesel also need 10 min driving before it's warm the wife's i10 petrol only takes half the time... 

Yeah, I saw that it was posted in the petrol forum now too. 
 A petrol should be a lot quicker than 10 minutes to warm up.

[phiber]

I'm looking at options of various Android apps which support logging of coolant temperature + revs + speed through a bluetooth obd2 dongle.

[Shambles]

Torque Pro will do that for you.