James.
Thanks for posting that info about the radiator. I had a heck of a time about a month ago getting a couple of my cars to pass nox. They are an 88 and 90 300SEL. I just boughy an 87 300E that smokes big time. The PO told me that it barely passed smog. After I correct the smoking problem, I'm going to do a little research on the cooling system. I have digital pyrometers, access to radiators at wholesale prices, and of course cheap labor. I just had a 560 SEC smogged this weekend. I checked it on my machine which is only a 4 gas analizer, and the readings were very low. I can't check nox, but it passed the smog with very low nox. I replaced the radiator about a year ago, because it was running hot. I know none of this is scientific, but it has got me thinking. Today I will go into my 1979 manuals and look at the system on your SL.

Peter

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