98 Toyota Camry 4 cyl engine noise

When was the waterpump replaced last? Your timing belt could be loose too. The timing belt tensioner may be worn too. Switch to a high mileage type oil that will slighty swell the valve seals and stop most of the smoke.

The waterpump is original and it doesn't leak. Thanks for you comments.

The frequency of the noise is about 120 per minute which is much lower than the engine RPM of 600 at idle.

Correct me if I am wrong here. Since the things (water pump, idle pulley, etc) connected to the timing belt, drive belt spin at rate close to the engine RPM, they shouldn't cause the noise?

The water pump is still suspect with that many miles. Most people change it on the 2nd timing belt change. IF you say it is coming from the timing belt area it most likely one of these:

1. Water pump
2. Belt tensioner
3. Belt (loose,frayed)
4. Oil pump So in any event the cover needs to come off and those things inspected/replaced. While cover is off there are several seals on that side of the engine that should be replaced. Dont forget the O ring behind the oil pump. Just because a water pump is not leaking a bearing could fail at anytime. Yours is on borrowed time.

I agree with Rob. I just had the same thing happened on my 93 Camry and it turned out to be the water pump. The bearing had failed and it was making a rattling noise. Take at least the top half of the belt cover off and cycle the engine a couple of times by turning the crank bolt to see how it feels and take a good look at the condition of the belt. It will only take a few minutes. If you want to drive another 30k it is obvious that you have to fix the problem. Alex.

From memory the auxillary pulleys (w/pump-oilpump and tensioner) are running at about double the cam shaft speed or at about the same speed as the crank. This may give the impression the noise is faster than the motor if your ear is referencing against the overhead (cams and valve gear) gear noise. So it maybe one of those auxillary drives mantioned above.

Sometimes a slightly ragged edge worn off the toothed belt (main drive belt) can make a noise as it runs around the pulleys and because there are more small pulleys than large, it can also make the noise sound fast. Then you have the alternator and p/steering and AC drives and their belts.

I'd try pouring a small amount of water on these belts to see if the noise changes or goes away before investigating the cam-belt.

There are cheap stethoscopes available at some auto-markey places which can help trace thenoise as well.

Jason

I just came back from a shop. They replaced the water pump, idle pulley and second pulley. With $500 spent, the noise is gone.

The mechanic kept the old parts and show me that all the bearings on the water pump and two pulleys were making noise. I am happy that the problem is solved but I am puzzled about all three bearings go bad almost at the same time.

I had my second timing belt replaced 4 month ago. Since then, I drove

10K miles. Is it possible that the timing belt wasn't tensioned correctly, may be too tight? I ask this because the engine wasn't as smooth as when I had the timing belt replaced for the first time.

Thanks again for your comments.

All prelubed roller and ball-bearings and I think some of them maybe double row here, to provide lateral strength for wide-belt drives, will start making ticking sounds after a relatively small number of miles as the grease settles away from the cage somewhat giving rise to cage rattles. This does not mean the bearing is worn out. Try listening to any alternator (spin it by hand) after a year's service,...it will make lots of cage-ticking sounds. The real problem arises when the case-hardening starts to break-down in the ball-tracks (both inner and outer tracks) or the balls themselves. This causes a growling sound which may have an periodic grr-grr-grr sound to it. This is because only one part of the race's track has started to fall apart. So it's important to differentiate between these noises.

One thing that some folks dont realise, is that the grease for a ball-bearing is for the cage lubrication only which has to keep the rollers/balls apart as they run around their tracks.

The real culprit was probably the water-pump. Once the pump's water-seal starts to leak small amounts of coolant, some of it gets into the pumps bearing, causing it to rust and generally get noisey real quick.

The pulleys which were replaced, maybe were not replaced the last time?

Jason

Who changed the timing belt 4 months ago? Sometimes, shops try to minimize price by changing the timing belt only. The water pump and idler and tensioner bearings should be removed (one bolt each -fairly easy when you're right there) - and checked for smoothness of operation, or just replaced as preventative maintenance. Sounds like the first mechanic didn't check them. Now that you've already paid twice, may not be the best time to suggest this, but another useful preventative maintenance job while they're there, is to replace the oil seals - especially the crankshaft and oil pump oil seals, but really not to much harder to also do the camshaft oil seal. It does cost more, but if you replace the belt, oil seals, bearings, water pump and accessory drive belts, you're virtually guaranteed of no future problems. Not a bad idea to replace the spark plugs, valve cover gasket and spark plug tube seals at the same time. While we're at it, how about power steering fluid, brake fluid, transmission service? All good ideas for minimizing future expenses and maximizing longevity.

Oops. Misspoke. Sounded like I said one bolt to remove the water pump and check bearing. One bolt each is for the tensioner and idler bearings.