So I was driving down the road at about 45mph and a random grinding noise happened from im pretty sure the front of the car. I dont think there was a loss in power because i pressed on the gas still and it kept driving. Also the RPMs had to do with the noise the higher they were the more frequent the noise. A few moments of driving like that I pulled over and put it in park, I didnt see anything leaking or anything broken so I got back in it and drove home and it drove back fine as if nothing happened. Any one have an idea what this could be and if I should get my wallet ready?
Some basic information is that I drive a 2000 Blazer zr2 with about 120k miles if that makes a difference... Pls hlp

 

You`ve said"The noise increases with Rpm`s!" It could be a number of things.It could be a bad power steering pump,a failed bearing in the alternator,failed bearing in the water pump or there`s a problem within the engine.So does this happen only when you drive it?

 

It only happened this once when i was driving today on one road that ive driven on a lot of times, It stopped when i parked to look at it and once I got close to my house I floored it a few times and it seemed normal. And i dont know if this related but about two days ago in the morning when i started it it was making like a noise as if some plastic and metal were hitting in park and drive but when i turned it off and drove it later it went away

 

Next time you're driving and it makes that noise, shift into neutral while you're rolling and rev the engine. Let us know what the noise does under those circumstances.

 

So it happened again yesterday and when I threw it in neutral it stopped and when i stepped on the gas pedal it seemed fine. When I went back to drive it drove normal once again... So im guessing its a transmission problem?

 

Happened again today and When i put it in neutral it was still making the noise but the engine was fine, When i slowed down I guess it down shifted and then it stopped making the noise and I put it back into drive and it was fine, It seems to be happening when i drive around 70mph

 

I agree, it doesn't sound like a problem with the engine or belt driven accessories. I've read threads here about 4wd engaging on it's own while traveling. Does it sound like the front differential is partially engaging? That would make a grinding noise in the front of your zr2. I would investigate that before I tear the transmission apart. Specify in your search whichever you have, 3 or 4 button system. It seemed like that happened more with the 4 button 4wd.

 

One of the craziest noises I ever heard was when a plastic shopping bag got caught underneath a car... it would come and go, sticking to undercarriage when wet... flapping (buzzing like a hornet, really) at certain speeds & not at others.

Same with air deflectors up under radiators that come loose and rub the belt or fan.

Not saying this is it... but it's free to put it on jackstands, throw a piece of cardboard down, lay down & look underneath.

 

hmm I have a 3 button system but next time it happens ill put it into 4 wheel drive and see what happens then, My check engine light is on too but i dont think it relates its a p0147 and sometimes a p0300

 

Sooooo some good news, The same noise happened again and I put it into 4 wheel drive and it stopped.... What does this mean? I dont know but its not my transmission so im happy.. I dont see why it would be trying to engage though, It usually happens when im driving up an incline and im above 50mph