On my rad fan motor I have a small tube that I think is an air vent. It's been closed off at the end. I wanted to confirm, is that a vent, and is it that ok to be sealed off?
Fan vent tube someone closed off?

 

You don't say what model,but yes the early fan motors had vent tubes. Later models either had the tubes blocked or motor vent areas were sealed over. Vents caused more damage than what they were worth.

 

1999 Polaris Magnum 500. Can I just leave it alone?

 

Leave it alone as these motors first came out with vents and later models with the same motors were sealed off. Whether this block off was factory(can't remember) it's a good idea to leave it blocked. Water could get into the earlier ones and damage the motor. Shows to be a fan assy that is updated and can replace the separate 4170013 or so the add says.http://www.ebay.com/itm/New-Polaris-...9WsmT0&vxp=mtr That is if the old one turns out bad.

 

In the old days we used to see small tubes with plugs similar to that coming from electric motors, they were lubricating tubes...remove the plug and add a couple drops of oil to lube the bearings. Nowadays everything is sealed, just wonder how many younger fellows even know what an oil can is?

 

You didn't lubricate these motors. The tubes were strictly vents that caused more problems than they were worth on letting moisture and dirt in. Polaris used the same motor on later models they had a resin type sealant over the existing vent hole in the motors. I guess they reserved the right to change their screw ups.. Here's the newer motors,no vents.