camaro_junkie

I'm 90% sure it's the EGR valve.

Last night I was driving home and over the stereo I could hear this noise that got louder with RPMs and seemed to have a frequency to it... not too sure if it was the same frequency as the engine rotation.

Today I started it up and listened as hard as I could. It SEEMED to be coming from the EGR valve. I forgot to check if the noise was also on the driver's side, but I'm pretty sure it wasn't. It sounds sort of like someone playing the saw if you've ever heard that, or like a tuning fork but not quite as high a pitch.

Anyways, when I held a screwdriver against the diaphragm the sound deadened a little. So my theory is that the spring in the valve has had it and it is opening a little with each exhaust stroke. Also, the EGR solenoid and control is only about a year old.

Any opinions?

ede

egr is about the last thing i'd look at if you have a noise problem, but you're there and heard it and i'm not and didn't hear it.

camaro_junkie

Like I said, I'm 90% sure that it is the EGR valve making noise. And let's be optimistic here because I don't have the time or money for a rebuild yet. But if anyone has any thoughts on my theory, I'd greatly appreciate it.

demicon

Squeely sound...

serpentine belt (old or perhaps there is coolant on it from a leak)
berrings in any pully (though this is usually a grindy sound)
alternator berrings/bushings


A vaccume leak might also sound that way, but I could be wrong.

camaro_junkie

Definitely not the belts or pullies. Could be a vacuum leak. Still betting on the EGR though.

THEGENERAL

sure fire way to eliminate the belts or accessories attached to the front of the engine pull the belt or belts and fire it up see if the noise is still there if not then you have determined for sure that it isnt the accessories

camaro_junkie

I'm sure about this one.

Nocturnall

Are you sure it's egr and not smog? I thought the egr didn't do sh*t till your on the highway. My smog pumps makin all kinds of noise but I just ordered a replacement pully for $24 so that'll be gone soon.

camaro_junkie

Well the EGR doesn't come on at idle, but that's irrelevant if it's broken and opening on it's own with only pressure from the exhaust.

camaro_junkie

bump

Nocturnall

then take it off and run the car, see if you can hear the squeal over the loud a$$ exhaust that pumps out right there...

z28monster

iTrader: (1)

could be your alternater also... take the belt offof the alternater and start the engine for a couple second and see if the noise went away... ive had this happen to me before and found out by using this method... if u have a surpintine belt you wont be able to do this though.

camaro_junkie

Turns out it was the water pump bearings. The funny thing is that the vibrations from the bearings at idle were being transferred through the engine at idle, hence the EGR theory. At idle there was no sound at the pump. When you rev it up though, then you hear it from the pump. The great thing is that both belts wrap around the water pump pulley, so you can determine easily if it is the water pump. If it were a toss up between the smog pump and the alternator, it would be hard to tell. Another funny thing is that the pump never leaked, so there was no sign of trouble.

So far I've installed the new water pump... and I mean NEW water pump. None of this rebuilt crap. But I didn't get everything back together yet and I wanted to let the sealant dry completely. So my car is still at my parents' house (where I always work on my car). I'll have it on the road tomorrow.

Back to the EGR. I'm still skeptical that it's working properly. I'm gonna test that tomorrow after I finish with the water pump. At the beginning of this thread I was very adamant about the problem being the EGR valve. That was just wishfull thinking. Hmmm, 15 minutes to change the valve versus 6-8 hours for the pump. Which would you rather do?

87CamaroMan

That seems to be a really long time to do a water pump.. I can change mine in less than an hr.

THEGENERAL

ive never had a water pump on a camaro take that long ???????...should only be a 1-2 hour job at most but sounds like your taking your time with it and making sure everything is cleaned off and sealed up good ...better safe than sorry ......

like i said before if you would have taken the belts off the car and reved it up you would have known that it was someing with one of the accessories then it would have been alot easier to narrow down but anyway glad you figured it out ..sounds like you caught it in plenty of time ...ive had many pumps go out on my before and only about half of em started leaking before i changed em ....it does happen quite frequently believe it or not but most people drive em when the bearings are going out until it has no choice but to start peeing out the pisshole ....lol...

camaro_junkie

If I "would have" taken the belts off. I did take the belts off. Yesterday was the first chance I had to diagnose the problem. As far as time goes, that includes two trips to the parts store, 1/2 hour to clean the old gasket off (which was the hardest part), 1/2 cleaning the bolts while waiting out the rain, and 1/2 hour diagnosing the problem and figuring out how to loosen the powersteering belt. So it still took 4 or 5 hours, but there were no problems.

Also, does someone want to help me out with the torque specs for the water pump. The GM shop manual has torque specs for the water pump in the engine section and the cooling section, but they are different specs for different bolts. The Haynes manual has one torque spec for all V6 pump bolts. I did 20 ft-lb for the 4 bolts that used a 15mm socket, 20 ft-lb for the 4 bolts that required a 13mm socket and 15 ft-lb for the 5 bolts that required a 3/8" socket. Does this sound good?