rortizjr

I had to replace both the serpentine belt and tensioner on my 1985 vette but now the tensioner jumps around when I start the vette. what can cause this jumping of the tensioner which is brand new?

Muffin

"Jumps around" can you be a little more specific?

ejscarfo

The tensioner has some serious resistance, something doesn't seem right here. Is that what you replaced or just an idler pulley?

rortizjr

Sorry the tenisor starts to move up and erractic and it is brand new. I do not know what is causing this, thanks for any suggestions

ejscarfo

What was wrong with the old one that you replaced it? I would check the belt routing and make sure no other pulley is loose or out of alignment. Also, check the bolts on the tensioner you installed, make sure they are torqued to specs.

jhammons01

Also, check the other pulleys to see if they are trying to lock up.....if one is jamming that may cause a jerky moment that the tensioner has no bearing upon

rortizjr

ok will check into that

383vett

Does the engine have a miss. A bad cylinder will give similar results.

Muffin

Was the new tensioner properly indexed? My 85 has a slot/tab arrangement.

rortizjr

the old tensioner was also moving back and forth so I replaced it thinking it was bad, but now the new one does the same thing. The tensioner is sitted in the slot, all pulleys seem ok and the engine has no miss fire.

FOURSPEEDVETTE

They will have a slight movement normally. The only time a tensioner needs replacement is when it starts squeeking or squeeling or the tension is too weak due to age. A slight bumping up and down at the tensioner you may be seeing on your new one may be normal. That's why the tensioner is spring loaded instead of the "old school" engines of the 60's and 70's that just had stationary pulleys and locking bolts on the power steering and alternator brackets to tighten the belts in place.

rortizjr

ok, but when the tensioner is moving up and down somewhat erractically it also makes a noise that sounds like metal banging.

Muffin

Two questions:

How much up and down? 3 inches?

Can you isolate the source of the noise? Is it from the tensioner itself or someplace else?

Little_Red_Corvette

Did you ever resolve your problem? I have an '85 and did some modifications to it, I hate to say I deleted the AIR pump. Now that I have put everything I am seeing the same problem There is an indicator mark on the tensioner when I rotate the tensioner I see that the marks are more obvious. The belt I have is 89 in long, I think I will shorten it to 87 in. long putting the tensioner in a more optimum tension area. I think? I'm very tense.