I have a 96 4runner with a 3.4l 5VZ-FE eng. It started with a smell coming from the engine compartment after a small road trip. Couldn't find the the area of the smell, so let it sit for a while. After about 4 hrs of sitting, I started it up and it had a low pitch sound coming from the front of the eng. It was sort of a grinding sound, like a bearing possibly, temps are staying fine, sprayed some wd[40 on all the pulleys, and the noise seemed to lessen, but not going away. Any advice is greatly appreciated.

 

A bad water pump bearing will emit a grinding sound. Sometimes the sound is from the bearing itself, sometimes it is from the impeller grinding against the housing. Typically, a bad bearing is preceded by a slow leak from the pump weep hole. That lets the owner know that the seal is compromised and water is getting to the bearing (meaning imminent bearing failure). You can remove the belt and spin the pulley by hand to check for noise. There should be no discernible play in the pulley bearing.

The power steering pump and A/C compressor can also be sources of noise.

 

Most likely the WP. Mine had the odor after a trip for two years before I finally changed it along with the Timing Belt. It was leaking around the gasket, not the shaft or weep hole. The gasket had dried out and cracked. Probably would have continued to provide service, but at 128K, I didn't want to push my luck with everything. Go ahead and replace the tensioner for the TB too, don't want to have to go back in for that.

 

Thanks, taking it in to get the water pump replaced and the timing belt replaced..

 

I'm sure they'll check the seals while they are there, but I would go ahead and replace those as well as the thermostat at the same time. You'll save yourself 1.5 hours of labor to do them now even if they aren't leaking (seals) or stuck open/closed (thermostat).