You didn't say which model engine. Cat/Perkins makes a lot of 4's, now up to 175 HP on the top end and I don't remember on the bottom. Smaller ones are built on license from Shibura and those can be a bit iffy. I have one of the smallest, a 3 cylinder, in my mini-excavator. Radiator plugs pretty easy - there isn't a lot of extra cooling system room available in such a small machine. Mine has been in the red several times before I caught it and I haven't had any noticeable problem - I have close to 1,500 hours on it now. Probably not a good sign that Cat as gone to Kubota engines in their new skid steers, mini-excavators, and compact wheel loaders, but it may just be a sign they were having trouble meeting emissions, have to re-engine every product in their lineup, and they could reduce development by using somebody else's engine. If I were you I really wouldn't be greatly concerned because there s a margin between start of red and oops, there is a problem. Watch your oil consumption, change your oil if you feel you may have cooked it, and go on. My little 3 cylinder uses a quart about every 50 hours which is a bit high but my engine has always had a lot of blow-by out the draft tube, especially after letting it sit idling for a long time.