Ihave a73 240z with 3 row radiator and MSA shroud. Yesterday after just leaving home car started to miss and die. After several starts engine loudly backfired two times.Managed to get back home to check things out,found one of plastic fan blades had bent under the shroud and gouged the rad. Then at that time noticed the gap on remaining blades was very small .Ihave driven over a year with no pr0blems. What would cause this? Been told that my fan clutch takes a long time to engage. Am going to take car to rad. shop on monday. If rad. not repairable want to go for a 4 row radiator ,new plastic fan and clutch. My concern being that since gap is so small will this happen again? The other option is one or two elec. fans with new 4 row rad. Hopefully someone has some feedback on this d*** Funk

Adding another row to a radiator will move the surface of the radiator closer to your fan, so I'd find out why your fan kissed the existing radiator and fix that issue before installing a thicker radiator. There should be a good sized gap (around an inch if I recall) between the radiator and the fan

Possible causes that I can think of:

water pump (bearing bad, or broken shaft)

fan clutch (bearings)

radiator support pushed rearward due to accident damage

Also make sure you get the correct clutch for your Zed. The later 280ZX clutches will put your fan too close to the radiator.

I pulled everthing off the car. One fan blade bent rather badly ,others had tip wear indicating they had been rubbing. Waterpump looked ok no wobble or noise ,but probable replace it anyway. Clutch bearing felt ok,the fan had 4 half moon spacers this might have been putting it too close to rad. Tried without but fan blades came too close to idler pulley for ac. Thats probable what they are for. No one in this area seems to carry fan blade,probable have to go to dealer or MSA. Taking rad to radiator shop tommorrow, hope it can be saved. Thanks for the replies d***