We had a 1991 Contessa with a 3116 Cat. I had all the problems Bob was explaining even after I changed the radiator, after cooler and installed a larger oil cooler. Not as bad an overheat and was pretty good IF we were not towing.
As Gerald points out get the hydraulic cooling system checked out by someone who knows what they are doing. There are two parts that are critical to this system working properly, the hydraulic fan motor and a temperature sensing block that directs the fan motor to turn the rpms that are needed to cool the unit.
The 1991 Contessa was on a Gillig chassis and so that is where I speak from regarding the temp block. When the fan motor was not working correct it caused a mid overheat just going over the so called mountains in Tennessee. Climbing up to get out of the Badlands in summer it went over 250. We always had to unhooked anything towed on a real steep or long grade if the system was not working in total.
When the temperature block was not working the fan motor never ran more rpms than when it was on a cold or just warm motor, almost just lazily moving. If the temp block is working it sometimes would sound like you have an airplane in the engine compartment, but the engine never overheated. It did not take fan long for it to run at a high speed to bring coolant back to normal operating temp while you were climbing and towing.
And Bob I wouldn't be too discouraged as although CAT is ALWAYS pricy those items they replaced may now not haunt you as a breakdown some where in time on a Sunday afternoon in no mans land. They were over 12 years old and as much as our coaches set it is most always worse than if they were in use.
We picked up a 2004 Marquis in Costa Mesa in August 2012 with 36,000 miles and in May 2013 we outed $4700.00 to get the Allison from locking up in 5th gear. Seems that there has been a problem with this trans during warranty period and then at 32,000 mile just 10,000 miles prior to us having the same problem at 42,000 miles. I just conversed with a retired Allison fluids engineer and I am going to write Allison - but I expect I will get nothing but the corporate jargon of out of warranty. After the initial being peeved about the cost I am fully back to being totally happy with the Coach and would not trade it for anything. We were and are extremely happy with our BEAVER coach(s).
One aside we learned when we picked up the 2004 and had a great bearing on us getting it. It is the last year Beaver Coaches were built in Bend. It is also very near the last time when you could get a CAT, built by CAT, in your coach. While we were in Costa Mesa at brokerage there were two New Coach Owners that came in and with less than 8000 miles both had their C-13 CAT's blown. NOT happy Campers to say the least.
CAT no longer makes their motors due to the emissions requirements and whomever does does not do what CAT did, obviously. We listened as numerous others are taking their existing coach's and having them refurbished as they have the running gear that will last most all of us a lifetime of RVing but just want to update. The quality that is coming out of most manufacturers since the early 2000's is non existent today. A Beaver, pre 2004 is a gem to own.
BOb, One thing we did change and this was learned from our Contessa as it had Koni's, get rid of the Bilstien shocks if you have and get a set of KONI's on. You want to experience a super ride this is the way to do it. No more porpoising or side sway roll, tire slap etc. Best pricing is from website in El Cajon California, SHOX. Make sure what mounts you have and call Koni direct in Tennessee to get correct part number. We had to drill out, and it is not that difficult if you do it in steps if you have a workshop, to get to the 3/4" hole in the eyes of the shock. They have a seperate part number that El Cajon did not show.
