So my FC T2 is fully stock with the stock clutch fan.

the old radiator was clogged.
I brought it to the mechanic because i dont have the time to do it myself right now.
he replaced the radiator but tells me that the car overheats.

When i passed by to see the car, the plastic shroud was not installed.

I didn't realize it when i was at his shop but now that i'm home it hits me.
Wouldn't the car overheat in 10 minutes when idling without the big plastic fan shroud installed ?

 

I don't think the missing shroud would make it overheat that quickly, but it would be a contributing factor to the overall effectiveness of the cooling system.

You said the radiator was clogged, and it was replaced, but was the rest of the cooling system flushed? There's likely still gunk.
How's the thermostat?

 

The radiator becomes very hot so the thermostat opens correctly i guess.
The mechanic was also thinking that maybe junk was clogging coolant passage through the engine but he cant get it off.

Last option according to him is oppening the engine. But it would be great to avoid oppening it because it has good compression.

Could corrosion block off the entire engine and cause it to overheat ?
And if the radiator becomes hot i suppose the cooling system inside the engine is still working no ?

Just in case he also did a pressure check on the cooling system. Everything si ok so it should have no coolant seal failure.

 

so step one should just be to put the shroud back on. i've never run the car like that, but without the shroud the fan may not pull air through the radiator.

if you do that, and there still is a problem, then the thermostat is the next thing on the list