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2003 Corolla has a rattle at idle. Its sounds like its coming from the belt tensioner. Its not a constant sound.

When I get time I was going to pull off the belt and check the bearing in the tensioner pulley. Anything else I should be looking at? 

The A/C is no longer blowing cold air and the rattle noise only happens when the A/C is on.

That generation is known to have noisy belt tensioner / bad idler pulley (serpentine belt runs around this) / bad belt design.  The A/C not blowing cold could be an indicator of an excessively loose belt or something with the A/C clutch.  Could be dragging, causing the belt to slip/jump - leading to the knocking / rattling noise.

Definitely check for noise with the belt off.  If that definitely is the cause, I'd look over all the pulleys, make sure there isn't anything damaged or not turning smoothly.  Double check the tensioner - if the little shock looking thing is leaking or otherwise shows physical damage - probably best to replace the whole tensioner.  There are a number of aftermarket belt tensioners - I would also try running something like a Gatorback Poly-cog or similar replacement belt.  Way better than the OEM Bando belt.

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What do you recommend for a replacement tensioner, hydraulic or spring?

From searching the site it looks like a hydraulic dampener is better than a spring.

I made a mistake in the year of the vehicle. Its a 2004 Corolla.I know we replaced the belt a few years ago with an aftermarket. Not sure what brand.

This A/C system uses R134a refrigerant? Can I mix another refrigerant in (12a) if its low?

I have an A/C manifold test gauge kit.

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R134a is still available. I'd be pretty sure it's R134a given the year. If you have R12, it's getting pretty valuable for people with pre-1995 cars — you can get a good price for a can..

I tested the A/C system with the gauges. I am getting 22 psi static. Definitely low, the compressor is not coming on anymore.

On another note I noticed the valve cover gasket is leaking along the back. Any favorites for brands to replace it with (Fel-Pro)?


All I can say is I prefer rubber to cork, if both are available... and Rock Auto is a good place to buy from.