I have a problem that started this morning. When I started up the 4runner (98 Sr5 auto 4x4), I heard a screaching coming from what sounded like the drivers side of the truck, under the hood. When I turned off the heat, the screach stopped. I haven't gotten a chance to take too close of a look yet, thanks to DST and it being dark when I got off of work.

Wondering if anyone has had this happened before, and/or what you did to fix it. Thanks.

 

dont use the heat?

 

While that might be reasonable down in Atlanta, here in Connecticut, it's starting to get just a little bit nippy.

 

With the blower motor running, does it squeal more when you turn on the lights?

 

My guess is you need to tighten/replace your alternator belt... That headlight test is a good idea.

 

I agree.

 

If it does squeal more with the headlights on, would that point to the alternater belt as well?

I actually just had my timing belt and other drive belts replaced about a month ago, so would that make sense that it maybe stretched out a bit and now needs to be tightened?

 

By any chance, could you A/C or Defrost have been on? If so, that leads me to A/C compressor....

 

Investigated this morning. The screaching only occurs when the fan position is set to defrost. So does that mean it's most likely the blet that drives the AC compressor, as gapguy suggested?

Would some belt conditioner likely get rid of the problem, or is this going to require going in there ant tightening the belt?

 

Yep, its the A/C.

Take a look at what's happening under there. When the defrost is ON, does the belt just spin around the A/C pulley, and the Pulley not actually turn? Is the belt tight?

Could be a loose belt, could be a bad A/C compressor.

 

Check the a/c belt tensioner. Easy to get to from underneath, right under the a/c compressor.

Well, easy to get to after you remove the skid plate!

 

Well, sure enough the AC compressor belt is pretty loose. Thanks for the help, guys.