timing belt replacement

**Ripp** · 11-01-2007, 05:36 PM

inching up on 100k miles, and looking at replacing the 3.5L timing belt "just because." The service manual says that I need to pull the valve covers and loosen the rocker arm ass'ys....

Are you kidding me?

Is this really necessary or only if you're pulling the gears as well? The SM isn't clear on that issue, as they lumped the belt and sprockets together in the same section.

Anyone want to elaborate? TIA.

**high888** · 11-01-2007, 07:41 PM

Ripp, don't F with the timing belt. I have had experienced techs replace them, and they can screw it up. The belt can "hop" if installed incorrectly, and the car will run horrible. Leave this one to the experts unless you really know what you are doing.

Also, if you are close to hitting 100k, get it done NOW. You don't want it to break. The 3.5L is supposed to have valve reliefs on the tops of the pistons, and I have seen pictures with the reliefs. Nevertheless, if a valve should make contact
with the piston, you are looking at a grand or two for the repairs, depending on the extent of damage. Do not delay replacing a worn belt.

**bigjim** · 11-01-2007, 09:18 PM

Do the timing belt on the books schedule. Also do the water pump and idler with the belt as the pump and idler will NOT make two intervals. If you opt to do this on your own follow the steps to the letter and after releasing the idler to tension the belt, turn the engine BY HAND to make sure the belt is properly in time before starting the engine, you will not regret this 5 minute step for the peace of mind that you will not smash the pistons and bend the valves. I have changed countless timing belts and have caught my error in this step at least five times, don't skip this step!

**fnkychkn** · 11-01-2007, 11:35 PM

timing belt should be replaced at 105,000 miles (168,000 km).
as bigjim said, while you're in there, replace the water pump, belt tensioner and tensioner pulley assembly.
if you are not going to loosen the rocker assemblies before removing the belt, use extreme caution not to bend valves from piston contact.

**Ripp** · 11-02-2007, 12:30 AM

OK so if I'm getting this, the sole purpose of loosening the rocker arms up is so the valves don't contact the pistons when you turn the cams... but this only seems like it would be a problem if you were removing the cam belt sprockets and turning the cams that far...

Just removing the belt and keeping the cams/crank at or near TDC (or any other ref. mark) shouldn't cause this? How could it possibly?

Doing the hand crank check after install is a good idea though, I can see where not paying attention putting the tensioner on could mess up one side or both. But w/ some reference/TDC marks it should be pretty obvious, right?

You're probably right about replacing the water pump and tensioner, too... hey, I'd be in there anyway.

Just bought all 4 shocks, tension struts, tie rod ends, acc. belt, now add the timing belt, h2o pump and tensioner... $$$

Here's to another 100k I guess!
Now to find the time to actually do all of it...

and work on the GP, too!