What is the effect will some oil contamination is the cooling system?
Does it significantly affect the cooling efficiency? I have some oil the coolant on my boat. I do not believe it is a lot maybe a few oz, but I have been chasing some unexplained overheating issues. Will adding water wetter solve oil issues (if there are any). The other option is Dawn and several cycles of flushing the system. ie until the cows come home!

 

If you were going to flush with detergent then I would use cascade or another kind of dishwashing detergent, it foams a lot less than regular hand washing soap and easier to flush....

 

That small amount of oil won't make much difference in cooling, but it is definitely a sign of a potentially bigger issue which deserves rooting out and solving.

 

Actually a few here and there but the oil was added to the coolant via the bulge.
Engine running hot.
Water in the out-drive.
Engine leaking oil.
Shift cable failure
Trim cylinder seal failure.
Alternator only charging at 1100 RPM or more.
To name a few

I am still chasing the massive oil leak that has resulted in the oil being in the bulge, but this is the wrong forum for that question (1980 5L SBC). I would not expect a small amount of oil to affect the cooling or heat exchanger, but this a good forum for the question because 7.3 PSD have a tendency to dope their cooling system with oil. I did R&R the heat exchanger and found some kelp in there, but the blockage did not seem large enough to be the cause of the issue. new thermostat. I R&R the water pump to verify that it was marine grade and that the impeller was in place as well. I also checked the raw water impeller as well. Everything looks great maybe it's all fixed except the oil leak. This motor was R&R and overhauled by me. Then the engine was R&R and the four piece oil pan gasket was replaced with a single piece Felpro one. It still leaking big time!