Doubts about torque at motor head

Good morning, I post today with to see if they are so kind of clarifying a doubt.

Is it true that you should not torque the head of an engine when the weather is cold?

The mechanic tells me that, that it must be tempered that because the screws I do not know that, and that the material does not know what, it does not want to do my job.

If you can't, or yes, I hope someone can explain to me.

Thanks for your attention

He has some reason from the theoretical point. But what he does not take into account is that the manufacturing ingeñer

Thank you very much x the answer, you are right, and it is more logical to me what you tell me than the mechanic.

He tells me that the screws can be broken when torque in cold, and from there I do not take it out

Friend: The torques of an engine are always made in cold. There is a PARTE tolerance, also when the bolts are about to be cut is when they are already fatigued or very stretched, but not by the weather. I don't think your mechanic works in the antartid.