I hope someone can help.

I need to know if my SC tensioner assembly needs to be replaced -- instead of just the pulley.

A couple of weeks ago I noticed the oem SC idler and tensioner pulleys disintegrated, and SC belt gone. It looks like the idler pulley seized because it'* the one that is the most "gone" and I can't manually turn the bearing that'* left. I've got about 150,000 miles on my 2000 SSEi. I have ordered metal replacement pulleys (including an intense 3.4 SC pulley and puller) but I am starting to wonder if I need to replace the whole tensioner assembly because I can't seem to find any play in the tensioner assembly. I would think that I could manually test it'* tension / spring loading i.e. I could grab it and pull it in towards the centre of the engine ..let it go and spring action would snap it back towards the outside.

But no, I can't budge it! I look around the outside of the assembly and it seems as though there'* some sort of locking pin sticking up through the side of the assembly, perhaps locking it in place. I don't know...I would have thought that if the assembly failed there would be springless play in the assembly as opposed to it locking up.

I called the dealer and without looking at my car or getting the above explanation they dealer said the entire assembly must be replaced and that they don't sell the pulley on its own (which is a lie actually because the parts dept had the specific tensioner pulley in stock) Tensioner assembly cost $338 -- installation cost approx $350. Ouch!

How do I know for sure that they assembly is toast? And if it is toast, what would be th most cost effective way to replace/fix it?

Sorry for the long explanation -- better too much info than too little.

The situation you describe with the tensioner sounds normal. It has a great deal of spring pressure on it, and you just can't get the leverage needed to push it by hand. The pulleys have been known seize. Replacing all of them in that belt path would be a good idea. If you don't already know, keep in mind that the tension pulley bolt is reverse threaded, and requires a torx bit. You'll find out first hand how much strength that tensioner spring has while you're fighting to keep the torx bit in place, with the tensioner pushed far enough, and getting the belt into position. Another pair of hands will come in handy.

Get with Todd (Rogue) from Intense on what supporting mods he would suggest for the 3.4 pulley, and you will need a shorter belt.

If you go to www.dayco.com and look for find local retailer you should be able to find a local parts store that carries the tensioner.

just last week I had to replace mine and I found it at advanded auto parts for $62.00.

I had the same problem on my 2000 ssei, I ended up replacing both the idler pulley and the tensioner pulley....both the metal dayco ones for approx. $20 each from Advance Auto parts. Easy to install, took me about 5 minutes

yes just the pulley is around $20 but if you need the whole thing cost ya around $62.00

Thanks Archon,

I'm fairly big and strong and would not have thought the tension could be that intense. But glad I asked because I would have paid for a new tensioner for nothing. Thanks for the suggestion on changing all the pulleys. Got them all except the grooved idler pully (no 8 on the famous Dayco engine pic). The grooved pulley looked pretty good but what the hey, might as well get them all replaced while I am at. I will get a SC oil changed too.

This site has been a life saver for me. has many times put my mind at ease about what is really going on and whether I should attempt to tackle the problem myself.

Yeah, Todd has been an excellent resource. Intense rocks! I will be doing more business with them for sure. He did suggest the CAI but I will have to wait for now. Will gut the airbox for now. I also got the pcm, 180 stat, colder plugs, and the right belt too. I shoud feel an impressive difference over practically stock (except K&N panel, good plugs and wires).

The streets are almost dry up here now so I JUST CAN"T WAIT !!!

thanks for the PM! Looks like I might not need the whole assembly but I'll check them out. Not sure if they service Canada.

Ok, those bolts are awefully tough. I got the T50 - fits nicely BUT I couldn't get even one of the bolts to come loose. I applied WD40 ('liquid wrench' stuff) a couple of times over the weekend, then applied pretty much my entire 220 LBs of weight on each of them; the tensioner, the upper and lower idler -- no luck. Yes, I'm turning them clockwise to loosen, even took the hammer to the end of my socket wrench handle -- still no luck.

I thought of adding some leverage to the socket wrench but not a lot of room to work with in there with an extension.

Any DIY suggestions?

Would a mechanic be able to get an impact wrench in there? Would this be the only way at this point?

Just to make sure, it'* just the tensioner idler that is reverse threaded. The others are standard threading. Do you have a breaker bar that you may be able to use? If not, try carefully adding a short pipe to the end of your ratchet to get a bit more leverage. Try some PB Blaster first.

Well that'* explains most of my problem. So to be sure it is only #3 in the picture that'* reversed threaded? It was the one I had the least leverage on, so I'll try an extension on the wrench next. Could GM makes this any more confusing!?!

What'* the drilled part of drilled 180?

Thanks again for your help!