What helps crocodiles stay warm when they are cold-blooded?

Crocodilians are ectotherms - meaning they get heat from their surroundigs. While their blood is not neccsesarily "cold", they do need to regulate their temperature by basking in the sun, moving to warm water, resting on something that radiates heat, etc. Conversely, if they get too hot, they will seek shade, move into cooler water, etc.