'97 Camry rattles inside timing cover

== You can run the engine with the timing cover off. Accessory belts only run alternator and power steering - for a short time, car stationary, you can run without those. Engine moving control rod is primarily for holding the engine under load, again you can run without that at low speed, no load.

Be careful here that you dont do unecessary work. If you replaced both idlers, its not likely they have started to go noisy by now or that they would get quieter as the engine heats up,..same goes for the w/pump. Noisy pumps stay noisy all the time. so do ball- bearings for the most part. What you may be hearing, and this is an opinion only, could be cam-drive gear-chatter or the engine pulley (harmonic balancer) centre-bolt may have loosened. The pulley would be easy to check,..the cam-gears, I'd leave alone unless the noise got worse. Try to narrow the area where the noise is coming from, by using a stethoscope. Check all the stuff up the front, including bolt-on gear such as alternator, PS pump, AC comp etc.

Jason

The last time I looked at this problem some months back the stethoscope indicated the noise right behind the upper timing cover. I may have to bite the bullet and run with the cover off to find out for sure. Timing belt has about 40K on it which is young but I might replace it at the same time. In another forum someone said they had a bad noise that went away when the belt was replaced. It doesn't make sense but otherwise I'm stumped. Thanks Daniel and Jason for the suggestions. Len

Running it without the cover is a good idea. A friend had a similar noise which had everyone beat, That eventualy turned out to be a loose crank-pulley which had been loose for so long it was rattling against its shaft-key. I forgot to mention the belt-drive pulley on the the exhaust cam (the top pulley). You should be able to test the cam and crank pulleys for looseness by hand (engine off of course).

The belt itself wouldnt be making such a noise, but the tensioner pulley which keeps the belt tight maybe. If I had to scale the liklehood of which item is causing this rattle, it would be: drive pulleys (crank and cam), tensioner pulley, then water-pump, loose idler pulley, cam endfloat, cam drive-gears noise.

best o luck,...Jason

BTW, make sure you replace the tensioner spring with a new, updated one (slightly shorter). Toyota had problems with those when OEM timing belts were stretching, obviously not enough tension on the belt to begin with. On V6 engines, a weak hydraulic tensioner also produces similar noises..

Aftermarket belts are fine as long as you use good ones. When Toyota had the timing belt stretch problem and couldn't figure out what was going on, they told the techs to use only Gates timing belts. I'd certainly recommend Gates timing component kits, belts and hoses from your local NAPA store. IMO, the OEM Dayco, Mitsuboshi or Bando will work but not worth the money over the dealer counter but they do yield more profit.

But make sure you have the updated (shorter) tensioner spring with the

Len wrote:

Glad you found the problem. I wouldnt have picked a loose drive belt,...but you live and learn.

Jason

Good find Len. I am thinking my 1997 camry might have the same problem. The timing belt and water pump got replaced and everything was fine for about 5-8K miles. I had both the belts replaced (drive and PS) at the same time. Now, it seems to make the same noise that Len is describing. The belt is a toyota oem part. Should I try to tighten the tensioner pulley? When the weather is reaaaaaalllly cold as it happened in texas during feb 07, the rattle would go away for all of 5-15 seconds when the car got started in the morning. Then the rattle would come back and at low idle, would stay on. Can the PS belt get loose too? Thanks for the help.

stony

Is engine 4 cyl or v 6 ?