Timing Belt Idler pulley and Tensioner
 

Hi,

Car: Volvo s80 1999 2.9 Non Turbo 110000 Miles on it.

Got my change timing belt and cam shaft seals on 100000 Miles.

But did not change Idler Pulley and Tensioner.

My Question is, If I do myself do I have to take off the belt again in order to put pulley and tensioner.
1:Can I just take the idler pulley nut off and put the new pulley in?
2:Same Question for tensioner.

Will appreciate correct procedure.

You need to loosen the tensioner, thus loosening the belt. Then you can replace the parts. You don't have to physically remove the belt, but it's almost the same job (just one step less)

Thanks,

Since this car has hydraulic tensioner, I meant tensioner idler pulley. I heard these hydraulic tensioner can be reusable and does not go bad. So I am changing the Tensioner Idler pully and timing belt roller/idler.
Please correct me.

Secondly I am worried about marks to be aligned, do I have to check the marks? Because I am not taking the belt off. Kindly advise.

You will absolutely want to recheck the marks to make sure nothing got moved in the process. It wouldn't be hard to knock something out in the process. Watch a youtube video. There are several that are quite detailed and helpful.

It takes longer to ask about checking the marks than it does to just check them and be safe. Yes, you need to make sure the marks are correctly aligned. The job is no different than replacing the belt with the exception that you are not removing the belt fully.

Hi, I Google my question but did not find any valid answer.

Why the marks should be aligned? when Engine is off and does not know what is going around. We need to aligned the marks before or after the timing belt tensioner release?

The marks are checked while the engine is stopped. Everything must be in the proper place when you reassemble otherwise you risk the engine not running, or worse, damaging itself by having pistons and valves contact each other due to the timing being off. The marks should match both before you begin the release of the tensioner and after reassembly.