jamie_sd

I have a 99 GS 400 with about 160k; I've had it for about 4 years now.

A couple of days ago, the fan on my HVAC started making a throbbing noise the varies with the speed of the fan. Medium volume music covers it up for the most part, but I'd obviously still like to fix it. Has anyone run into this before? Any ideas what it could be?
* Update:* figured out and fixed this myself (plastic access cover for cabin filter had come loose and a piece of paper was lodged in there).

The second issue with the radiator has to do with the plastic housing. Last time I had my GS at the shop the mechanic had me come out and look at the radiator. The plastic on the top part of the housing had faded to a lighter brown. He said that in his experience, this was a sign that the radiator was getting close to failing; he'd had a few come in that had "grenaded," as he put it.

I had a failed radiator on my last car (98 Maxima); I was alerted to it when the throttle stopped responding, upon which I noticed that temp gauge. I'm assuming the ECU detected the high heat and cut the throttle response. Does the GS have this feature too? Will it go into "limp home" mode before killing the engine? I don't want to have to worry about constantly checking the temp gauge. Or should I just replace the radiator now? I know an aftermarket radiator is a few hundred; is it easy enough to install that my gas station mechanic friend could do it?