Timing belt slapping againt plastic housing

[XT_]

This is driving me bonkers. It started happening about 6 months ago,. It goes away when the car warms up. I need to get the belt replaced anyway, but wondered what the heck could be causing that. The belt expanding or contracting? Maybe the plastic housing?

And I believe the engine is non iterference, meaning i wont suffer valve damage if the belt snaps..?


Thanks for the info!

[TourDeForce]

It is more likely that the belt is shredding and a strand is flopping around in there. Change that belt soon, before you damage the water pump pulley (if yours is one with the WP running off the timing belt), and use a Gates timing belt KIT. It comes with the tensioner pulley & idler pulley.

And yes, it is a non-interferrance engine, but with age & wear, the valves can still be damaged when the belt goes - especially if you're running at higher rpms or highway speeds.

Take care of your car, or pay the price.

[jamesmason]

Well for $555.53 worth of pulleys and timing belt and maintenance I had to go through with that same ordeal I'd get it replaced before it goes. because it can mess up your valves if it just happens to fall in the wrong spot, not likely but can happen. whenever you do it pay particular attention to the pastic pulleys that guide your belts especially the idler. all of mine the sealed bearing sets were trashed in and they all had to be replaced like I said keep an eye out and if they look like their bad I'd just swap them out to avoid having to do it again when your not expecting it.

[hectik1]

Take the cover off. I didn't have mine on for like 3 years.

[Kremithefrog]

Yeah lose the cover and if the belt is OK and has decent tension, ride on.

[BrApple]

i like the old idea of using a few washers to raise the cover so the belt wouldnt hit anymore ...

[XT_]

I heard about that before.. I should try that.

[pangloss]

The belt is not necessarily shredding, although of course it could be.

More likely, there is some belt slack between the crankshaft and the exhaust cam. Because of that, during the short time when the exhaust valves are closing the spring can push the camshaft around faster than the timing belt is turning. The cam pulley actually pushes the belt towards the intake side faster than the intake cam pulley is turning. That means slack in the belt can build up between the pulleys and the belt gets pushed up against the cover.

I don't know why this would start suddenly, or why it is worse in cold weather. My theory is not completely developed.

However the best thing to do, is when you replace the belt, whoever does the work should follow the procedure in the Gates Timing Belt Replacement Kit. This means they need to loosen the cam pulleys from the camshafts, (without letting the camshafts rotate!) and rotate the pulleys to take out all possible slack starting at the crank and working around CCW. I think that was the order.... Anyway read the directions. Then tighten the cam pulleys back onto the shafts.

My car did this noise for many years until I had the belt replaced properly and now it is much quieter.

[XT_]

i like the old idea of using a few washers to raise the cover so the belt wouldnt hit anymore ...

Did just that. Noise is now gone! :thumbsup: