carguy07

Anyone have a link to a DIY for the accessory belts on a 2005? I searched and could not find one.

Thanks!

kiwi

step one, draw diagram of belt routing (you will forget once it comes off)

step two, release tension on belt tensioner and slip belt off

step three, install new belt

carguy07

Uh, I think I got that part down. Was looking more for info like how you release the tension off of the belts. Is there a spring loaded tensioner on an idler pulley or does the alternator or another accessory pivot?

salimshah

RX300 uses two belts [3pt -> main, alt, AC] [2 pt -> Main, P/S]
Alt and P/S have the tension adjust points. If you have this type, I would suggest that you get a belt tension gauge, before you mess with them.

Serpentine belts which bend and snake, instead of running at the circumference (inside edge only), have a tensioner pulley. The spring maintains the proper tension, so it is very safe to replace them on your own ... other than remembering how the belt is routed. Relieving the tension with a ratchet or breaker bar, produces enough slack to slip the belt off.

Salim

carguy07

Ended up just doing the outer belt (the one that runs the alternator and AC). The other one was a brand new aftermarket belt that did not seem to be slipping so we left it alone. The one we replaced was also a brand new aftermarket belt and just like we have seen on other Lexus models, slipped even when tight. No, you don't need to write down the belt routing, it only goes over 3 pulleys with no bends. Yes, you use the alternator to tension it. Loosen the pivot blot on the alternator. Loosen the lock bolt on the alternator. Use the jam nut on the alternator to tighten or loosen the tension. Was able to get to the bolts with a socket wrench and a couple extensions. I think the bolts were 10mm & 12MM. Had to take off the plastic shield underneath and come from the bottom to get to the locking bolt. Sucked, but very doable if you have patience.

mandyfig

How come you had to replace the belts? Miles on the RX? Slipping, Squeaking?

carguy07

The original belts were replaced as preventative maintenance at around 70k at a local shop. They put new Gates brand belts on it. But the alternator belt was slipping and squealing a ton and not keeping the battery topped off. It was tight but still slipped. A new Lexus belt from the dealer worked perfect. This has been an issue on the RX300 too, so I figured that would take care of it. One of guys on the RX300 forum found the the grooves on the aftermarket belts were not right on the money causing the problem.
https://www.clublexus.com/forums/5850476-post9.html
OE belts actually cost a few dollars less than getting them from Autozone, so there is no reason to screw around with aftermarket belts.

cjs18

The attached SM exerpt for the 3MZ-FE engine should provide enough information to adjust your belts correctly. This is a 3.3L engine as used in a 2005 RX330. Note the distinction between new and used belts is measured in minutes for purposes of tension adjustment.

mandyfig

Thanks for the pdf! Good stuff.