Water Belt Tensioner

[myklos]

I purchased a 97 Z3 2.8 roadster last year just before winter. I put about 400 miles on it before putting into a winter storage location. It has 45K miles and is in good condition and drives great. I understand the concerns about the cooling system and I am buying the parts now for a complete replacement as soon as I can get the car out of storage, which is not until the end of April. Along with all the hoses, water pump, radiator, etc. I am also replacing the belts which appeared to be original. I am a little confused about the belt tensioner(s). On realoem.com I put in my VIN and I see both the mechanical and the hydraulic tensioners. Are these interchangeable? Is there any significant advantage/disadvantage to either one. I do not know which is on the car, and I can't get to the car to check until I get it out of storage. I would like to have all parts in hand before getting it back so I can complete the work without delay. If I can buy either one without worrying about fitment I will do that.

Thanks
Mike

[BimmerBreaker]

The hydraulic tensioners are a newer, better design. I upgrade to them whenever I have to replace the older style tensioners. You need more than just the tensioner though - they make retrofit kits on places like FCP. I just did this week last week with a kit for my E36 but it doesn't list compatibility for Z3's do don't want to link that.

But AFAIK you will need the tensioner, the idler pulley, and the bolt for the idler pulley as well as the 3 bolts for the hydraulic tensioner itself... not sure if those interchange with the mechanical tensioner, but the retrofit kit included those so worth mentioning

Idler pulley: https://www.fcpeuro.com/products/bmw...841228#fitment
Complete tensioner: https://www.fcpeuro.com/products/bmw...1287838797-1-2
Bolt: https://www.fcpeuro.com/products/bmw...lt-07119904677

That should be enough

[ptony101]

I replaced mine last year. Some things I learned. You can't replace just the pulley on the mechanical assemblies. They don't sell them separately. All the ones you'll find on the web are for the hydraulic tensioners, whether or not they are center hole or offset. The hydraulic tensioner kit from FCP is a complete replacement for the mechanical one. It has all the parts you need; I don't recall that anything from the old mechanical assembly could be reused. My advice: go with the kit from FCP. It has a lifetime warranty so you'll never need to pay for it again.