I have 1974 Delta 88 that has a 455 Rocket engine. It ran between 200 -220 temperatures while driving with the ac on this summer after rebuild. I have tried three thermostats 160-180 & 190 degrees and the problem continued. I purchased a new fan and a new four core radiator and the problem continued. I also had installed a new electric high pressure air flow fan in front of the radiator and the problem continued. All work was done by one of the best mechanic shop in town. Because the engine only had 800 miles on it and was still under warranty the shop owner had worked on a engine before that was over heating like mines and founded out that the ports were clogged. He took my engine apart and the ports were not clogged. He did some additional research and came across a waterless coolant and suggested that we try that product. He tried it and my car with the outside temperature being cooler the car engine reached 240 degrees and shut off. There is nothing else he knows to do to this engine and me either everything is new. The car has good air and water flow. The mechanic has came to this conclusion that the inside cylinder walls after rebuild are too thin. Any suggestions concerning this issues would be greatly appreciated.

 

When he had it apart why didn't he sonic check it. That would've alleviated what he "thinks" the problem is.
Some of these "mechanics" crack me up with their "opinions". Back it up once in awhile, you might learn something.

 

You should have started a new thread to ask your question instead of replying to someone else's 4 year old thread.

Anyway, the basic issue is your engine is generating more heat than the cooling system can dissipate. IF all parts of the cooling system really are functioning correctly and the radiator is adequately sized, that means the engine is generating too much heat.

Heat is generated by friction, so it is possible that something in your engine is "too tight" and there is excessive friction. One possibility since your engine was recently rebuilt is that piston to cylinder wall clearance may be too small. There are other possibilities as well.

 

Are you running a shroud?

 

Thanks for the info I was not aware of the ability to begin a new thread. I had read in some of the comments of other owners of 455 engines that had been rebuilt that something in the engine was to tight. I do thank you for taking the time to respond.

 

I moved your posts to your own thread.

 

These are not the temperatures of an overheated engine. You are worried about nothing. Your engine actually runs more efficiently at warmer, rather than cooler, temperatures. The reason your mechanic can't find a problem is that there is no problem to find.

Choice of thermostat has nothing to do with it as the thermostat open temperature is the temperature at which the thermostat opens, not the temperature the engine runs at.

If you had an idiot light instead of a gauge, the light would not turn on, and you would be on your merry way driving this car without thinking twice about the engine temperature. This is an example of having too much information.

 

You didn't provide the ambient temperature. These engines tend to run on the high side especially in hot environments. If the rebuild was done too tight it will be hotter now than before the rebuild. 200-220 probably could be tolerated, but 240 seems a bit high for a water cooled engine and could cause other problems. I once had a stubborn one like that. After checking everything the only thing it responded to was to remove the thermostat and plug the bypass. That helped significantly. When you get it cured, please let us know what the problem was. That will possibly help others.