I have a 1986 560sl (170K). It has been running at about 95-115 degrees unless I am going above 50mph. Two different shops have put the temperature gun on the radiator and showed me that it is hot in some places and cold in other places and diagnosing a clogged radiator. Since the radiator is only a few months old and was a new Behr, I took it back to the guy who installed it and told him what was going on. Problem, he refuses to admit that the radiator might be bad ("Behr doesn't make defective radiators, ever) or clogged. He is checking the thermostat (he put a new one in when he did the radiator), then said he was going to check the fan clutch (OK, can't hurt) but seems really resistant to check the radiator.

Does anyone have any experience with clogged behr radiators? I have heard that they cannot be rodded out because of the "turbulators" in the core. Can they be checked for flow rate without taking off the side tanks?

Any thoughts?