Humming sound in engine bay - Tranny?

[Diehonda]

After some searching I have not been able to find anything.

I have a 2000 Camry with an auto tranny and about 97K miles. Two weeks ago I had the timing belt, water pump, and accessory belts replace. I also had the tranny flushed.

From a stop to accelerating I will hear a humming sound from the engine bay. My wife hears it on the passenger side and I hear it on the drivers side. I took the wheels off and cleaned and inspected my brakes and it is still there. I have checked the tranny fluid and oil. Since the tranny fluid is new it is clean and topped off. The engine oil was pretty dark considering I just changed it about 2300 miles ago. I use Pennzoil.

Any recommendations?

The search on here brought up a bad water pump(which is new but eh?), lose belt(I checked the acc. belts and they are fine), and a a humming from the tranny due to pressure plate(but that thread was about a manual tranny)

The sound is constant. It speeds up as I accelerate also. More of a humming sound, not really a harsh grinding sound.

[bigbird]

do you hear it when the car is parked, or at idle? it may also be an exhaust leak if u do. what engine do u have?

[Diehonda]

I only hear it while driving.

4 cyl 2.2 I4

[Diehonda]

Ok, so I have posted my concerns on three other sites and I am hearing anything from a tranny on its way out(from nontoyota owners) and a pum that is on its way out.


Do pumps hum when they are beginning to fail? Luckily I have never had a pump fail before.

[Diehonda]

[ag6286]

Does it vary with RPM or Speed??

[davemac2]

so did it start AFTER the belts and water pump were replaced? If so, I think a timing belt replacement may cause this as the belt is seating in for the first few thousand miles, no?

Check your trans fluid at least to make sure the level is ok. Check it cold before starting in the morning.

As well, are you running your A/C? Sometimes a bad expansion valve can emit a low hum moan when it is bad.

Another possibility is a wheel bearing going bad.

dave mc

[dc_98_cam]

I would agree with davemac2 on this. It is more likely that there is something wrong with the timing belt installation. I recently replaced my timing belt. The no. 1 idler pulley, the one with the adjustment bolt, requires a certain procedure in order to be properly installed. I'm not sure, but I thought that I noticed some belt slack, initially, due to binding or sticking of that pulley. After two or three belt revolutions, I think it was finally installed properly, and is now functioning normally. However, I think that I will replace that no. 1 pulley at the next opportunity. ... Who installed your timing belt, you ... the dealer, somebody else?

[Diehonda]

I had the timing belt replaced at a reputable shop here in town.

It didn't make the sound before I took it to the shop. All of the work that was stated in the first post was done at once at the shop.

Do timing belts have to seat? What about the other belts?

They didn't change the pulley but he did say something about a screw that tries to back out and cause oil leaks and that he tightened it back down.



I am going to jack up the front and put it on stands and have my wife accelerate whil I listen. If that doesn't pin point it I will be taking it back to the shop and have them take it for a drive. They are honest people and I know one of the guys that works there personally so I doubt they did anything on purpose.

[dc_98_cam]

No ... what you are describing as the mechanic's installation doesn't sound exactly right.
You have to loosen the no. 1 pulley adjustment bolt and place the crank pulley and cam pulley at the 'TDC 0 line up' position, then with the pulley bolt still loose, rotate the crank pulley for 1 and 7/8 revolutions until the timing mark lines up with the 45 degree mark on the timing case cover, it's a line imprinted on the case. Then tighten the pulley bolt to 31 ft-lb. For a better description see:
http://www.camrymanuals.com/manuals/...hanical_I4.pdf
... print out pp. 26,27 for your mechanic.
I suggest getting a new pulley return spring from the dealer ... It is supposed to have a new specification in order to prevent belt slap or something like that ... $8 or so at the dealer.
I would get a new no. 1 pulley ... just to cover the bases. I don't think you have to remove the lower timing cover to do any of these suggestions, just the upper timing cover.
... One thing to look for before you replace the upper timing cover: there should be no appreciable belt slack either below the cam pulley, or adjacent to it on its right. There might have been 1/8 in of deflection, but probably not even that much.
............
.... This is what I would do. ... Then see if the noise is still there. My new timing belt had no 'breakin' noise that I could hear. I am not familiar with any bolt that supposedly comes loose and causes an oil leak.

[toyomoho]

Can you hear the noise when parked and revving the engine? Open the hood and listen to the passenger’s side of the engine where the plastic cover is.

[ASG14]

This is going to sound really stupid, but are you using your Air Conditioning? I ask as it has just started to get warm out. My '96 V6 makes a huming noise during acceleration with the A/C on, and has since I got it 38k miles ago.

[gumbydammit]

Every timing belt I have ever done whines for a while till the teeth "break in." The wife's wagon is doing it right now, 450 miles after the last belt.

My experience has been, if you adjust the belt right, it is a tad tight for the first 500-1000 miles, then begins to quiet down.

If the whir goes with the RPM of the engine (even a little louder whn you let off the throttle and the RPM's are coming down) there is likely nothing wrong with it.

If you are really worried, why not take it to the shop and have them listen to it?

I would not worry about it till 1200 miles have gone by.
It sounds like a belt break-in noise and you are most likely worried for nothing.

[gumbydammit]

As a matter of fact, if you PM me and give me an email account, I will send you a movie of the wifes wagon to compare it to yours to set your mind at ease.

[GaryS]

Did you check all of your fluids? Power steering pumps make a whining or groaning noise when low on PS fluid.

How about popping the hood and have your wife change engine rpm while you listen with your head under the hood. Try and locate an area that the noise is coming from