How to tell if Radiator needs replacing?
 

Just wondering any way to test this?

I was having cooling problems while in Arizona in my 260E. I have ordered a new viscous fan as it was not working, but I am curious about the radiator?

Any way to 'test' it?

Thanks

well,for starters if its not broke dont fix it,if you suspect a leak,there is a pressure test system you can use,you may be able to rent one from your local autoparts store,its a pump that fits over the neck of the coolant bottle,you pump up the pressure then let it sit,as long as it holds pressure after 30 mins,your leak free,if you disconect the upper radiator hoses/hose peak inside,look at the aluminum fins,they should look whitish/grey,if you notice allot of scally build up on the fins,you may want to drain the system add a bottle of coolant flush,fill it with water,then run it for about 10 mins at operating temp up dpwn the highway,then drain coolant system rinse,then refill with a 50/50 mix.its just a generall inspection that can tell you allot,also if you have very high mileage,over 100k,goodluck!!

Hard to see scale build up, but after mine was replaced it was a whole new ride cooling wise. And I have 228000K on the clock.

Check the temperature of the radiator outlet. It should be about 15 cooler than the inlet. If it's cooler, then flow through the rad is restricted.

Remove the radiator and clean it out both inside and out. After 20 years, the space between the radiator and AC condenser gets loaded up with all sorts of rocks, dirt junk etc. Also straighten out any bent fins and have the inside flushed.
http://img.photobucket.com/albums/v242/tjts2/Green%20Mercedes/a8.jpg?t=1274761615

http://img.photobucket.com/albums/v242/tjts2/Green%20Mercedes/a6.jpg?t=1274761644

It does not leak and I have removed it, cleaned it and flushed it with water until it came out clear.
I'll check the temperature using my laser sensor like you said.

Thanks guys

with plastic radiators
 

Weeping around side gaskets,Smelly all the time.Cooling no good after new water pump and thermostat.