"motor and two electric fans on exterior of (rear mounted) radiator all blow out the back"...

Don't laugh, but: After the radiator repair, were the fans installed properly? If the flex fan is pulling (as is normal) and the two electric fans are also pulling (they are probably facing the flex fan, on the other side of the radiator??) they could offset each other. Also: are the flex fan blades on "backward"?
Yeah, I know.... but repair shops occasionally make errors, esp on unusual configurations.
Is the trans fluid circulating through the radiator?

Good luck.

olroy, Bill N Y, and Gunner all bring up important issues. Although I have had no problems with the pusher diesel in mine overheating (although cooling IS compromised when the belt breaks ), I put in a Mag-Hytec pan on the transmission and cover on the diffy.

The tranny pan is finned on the outside and baffled on the inside, and made a significant difference in transmission temps. About 2 qts additional capacity on my 4L80E helps, also. Highest the transmisson gets on a 95F day on a 7 mile 6% grade is about 205F.

The diffy cover added about 1.5 qts additional.

quote:

Originally posted by Chris Dierl:
They sent the radiator out for refreshment.

That could mean anything.

quote:

and rebuilt the heads, as the gaskets had, in fact, failed.

That is certainly part of what happens to an overheated engine. Was the block deck checked for truth? What did the engine oil smell like? Was it analyzed?

quote:

After about 20 minutes, the trans temp gets there too, then they both continue on up to at least 235F, if allowed.

It follows that the trans would achieve the same temp as the radiator. They are often designed that way. Is there a transmission cooler" Is is installed before or after the radiator? Where is the transmission temp measured?

quote:

Shop says 210F is too hot, should be more like 190F, and is looking at fans and airflow. "Flex Fan" on motor and two electric fans on exterior of (rear mounted) radiator all blow out the back.
Running sans thermostat does not change behavior.

I think the shop is on the right track. They should indeed look at fans and airflow.

Also water flow, as Bill N.Y. mentioned. If the radiator is good, and that remains to be seen, then Bill's observation on pump impeller slippage should be checked. This is more common on stamped steel impellers on el cheapo replacement pumps. I have had stamped impeller pumps prove inadequate just towing a ski boat with a sedan, even with no slip. I use a high flow pump that starts with M. Either Milodon or Moroso. Edelbrock and Weiand sell them, too. I have always had good service from Desert Cooler radiators from US Radiator.

Now, as far as air, I will preface this by disclaiming any experience with gas or diesel pushers. I am talking through my hat here. I do not believe in flex fans on RVs. At higher engine rpm, they are designed to feather and move less air than they do at lower rpm. They are great on hot rods that overheat at slow speeds but are cooled adequately by ram air flow at speed. The standard thermostatic clutch fan is designed to move the most air when it senses the most heat coming through the radiator. My normal preference for a factory thermostatic clutch fan doesn't seep to be appropriate here, as the air moves in reverse compared to a puller. That is, the air moves from the engine outward through the radiator. This deprives a clutch fan from the ability to sense radiator heat and respond to it.

I think if I owned it, I would look at electric fans controlled by a thermostat. Perhaps a pair. 90-95 Taurus, Lincoln or Mustang electric fans blow 4500 CFM on high, about 3000 on low, I believe. And a good shroud making sure all the air goes through all the radiator.

A number of gas pushers have benefited from retrofitting air scoops on the side. Perhaps an air scoop underneath would also help.

I thought of you this morning, as I was in Long Beach and had time on my hands. Missed you and your band Sunday due to other commitments. That is a nice coach and is worth some effort.

Welcome to the Barth family. I love my 1975 class C and hope you enjoy yours.Please post often.