Correct tensioner bleeding procedure?

What does this text say?

Shall I pump up the tensioners before I put them in to the engine or not???

This information came in from one of our supplers recently:

Proper installation according to Porsche is as follows:

Submerge the tensioner in oil and pull the pin. Pump up the tensioner with your finger until no air comes out of the hole this is done totally submerged in oil. Once the tensioner is full of oil, it can be checked for leaks, prior to installing on the car.

Porsche says that the procedure of installing the tensioner on the car and turning the car over to pump the tensioner up is 100% incorrect and should NOT be done. From talkng to XXXX Sales and our German contacts, most mechanics use this method, and have been for many years.

Regarldes of how long the "install and pump by cranking" method has been used it is wrong - air pockets in the tensioner can occur an cause uneven pressure, this will appear to be a "weak" tensioner when in fact it is a improper installation.



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This post was auto-generated based upon a question asked on our tech article page here: Pelican Technical Article: 911 Carrera Chain Tensioner Upgrade

[Wayne 962]

Thanks for the comments / feedback. These tensioners are one of the most mis-understood items on these complicated 911s. Firstly, they are not oil-pressurized tensioners, they are oil-dampened, which makes a huge difference. That means they are spring-loaded and then oil filled to dampen them (like a shock absorber) during operation. I believe that the oil dampening reduces the spring-back effect of the natural spring inside and helps to keep tension on the chain and prevent "bouncing" of the chain tensioner against the wheel.

That said, in my two books, I do recommend priming them in a bowl of oil. I cannot remember what the "factory" recommends, but I do remember that the information the factory has put out on these is not 100% clear. Simply putting them into the engine and letting them fill up with oil by themselves should also be adequate too, as they have bleed valves in the tensioner that will / should bleed the pressure off. I would let the engine idle for several minutes before revving or driving it to make sure they are fully bled.

The bottomline is that you're not likely to have instant chain tensioner failure even if they are completely devoid of oil. If they are not charged / fed with oil, then I would suffice they would wear out a lot faster and probably cause other problems with the chain wheel. My conclusion is that either method would probably be okay, but I prefer to "prime" them "just in case."

- Wayne

[ChrisBennet]

I've had a brand new tensioner fail to pump up. For this reason I would make sure the tensioner "pumps up" before installing it. It's a lot easier to do this on the bench than take it out of the motor once it's in the car.