Slow warm up, even in 30 degrees ambient

[MarcB8.5]

Hi im new to the group, wondering if anyone can help. 
 

I had an issue with my car, engine was only reaching around 70 degree temp. So had the main thermostat replaced. Now the car does reach 90 and stays there well, but it takes a long time to get there. Maybe 30mins of driving. Obviously isnt normal still. Ive been told to change the 2nd thermostat by some other owners, but when i give my engine code to suppliers, they are telling me i dont have that part in my engine. Anyone resolved the slow warm up issue? Engine CJCD. 2.0 Diesel CVT

thanks alot, look forword to any replies

[Magnet]

First question first before moving on:-

Brand of new thermostat used? 

[MarcB8.5]

Hi Magnet. I’ll contact garage and find out which one they put in. Am i right in thinking that if it reaches 90 then its working correctly though? 

[Steve Q]

Yep 90 degrees is where it should be. Have you had a diagnostic check to see if any fault codes flag up? 

[MarcB8.5]

No i am checking fault codes tonight, as the ob2 scanner was too wide and did not fit, so waiting for extension cable.

So i dont know what thermostat was fitted, but i think it is faulty. 
so i started my car and let it idle for 10mins, after 10mins the temp gauge showed 50 still, but the top hose on radiator was quite hot. Am i right in thinking the thermostat is stuck open?

[cliffcoggin]

A long warm up time suggests it not fully closing. I have read a few cases in these forums where even new thermostats were defective. I guess that is why Magnet is asking about the brand.