[tomp]

H2 radiators are not efficient enough for the H2 from the factory. It is ample when everything is brand new but with the slightest amount of debris in the front grill slots, the efficiency goes to crap.

At a minimum, clean out the AC coil in the front by lightly spraying cold water from the rear of the radiator and then from the front. If that helps even the slightest bit, then you are on the right track. If not, try replacing the thermostat.

Finally, I'd have to question what you tranny temps are at prior to the engine overheating? It is possible the your tranny is heating up first due to it being a limo and then causing the antifreeze to climb with it. This is due to the ATF fluid running through the radiator on passenger side. I would suggest a very large efficient aftermarket tranny cooler to replace the cheap OEM unit. Since it's a limo, I would imagine the tranny is working overtime.

I would finally replace ATF and engine oil due to the excessive temps