98 V70 Serpentine belt tensioner question

Post by **98v70dad** » 17 Nov 2015, 06:39

My timing belt is due for replacement in 2K miles. I'm over the time restriction by 3 years (its been 10 years since the last belt change) so I need to get the belts changed. Anyhow, I figure I'll do the serpentine belt at the same time and probably the water pump since its the 2 nd belt change and I really don't know whats in there (OEM or aftermarket).

My car has 138 K on it and yesterday I started planning which parts to buy. That's when I learned of the recommended timing belt replacement interval 70K or 7 years. There's lots of good info here about the timing belt and serpentine belt but I didn't find a recommendation about the serpentine belts tensioner.

So my question is: Does the serpentine belt tensioner need to be replaced? Its most likely the original and the car is getting old. Springs lose their spring over time so I'm thinking it wouldn't be a bad idea. That said it seems to be working fine and doing its job. The serpentine belt looks OK considering its age.

Post by **mecheng** » 17 Nov 2015, 06:56

The quick answer, No.

Unless there is a problem with it, you are okay. The serp tensioner is very robust and simple. It is just a high strength helical spring. If it ever were to fail (never heard of one on these cars) it is no biggie.

Post by **Ozark Lee** » 17 Nov 2015, 07:27

mecheng wrote:If it ever were to fail (never heard of one on these cars) it is no biggie.

The instrument cluster lights up like a Christmas tree and the steering gets very hard. It will get your attention but nothing bad happens as a result.

On my Suburban it is a huge problem since the serpentine belt drives the water pump but that is driven by the timing belt on a whiteblock so, if you are strong enough, you could drive it until the battery died.

...Lee

Post by **98v70dad** » 17 Nov 2015, 07:37

mecheng wrote:The quick answer, No.

Unless there is a problem with it, you are okay. The serp tensioner is very robust and simple. It is just a high strength helical spring. If it ever were to fail (never heard of one on these cars) it is no biggie.

True. Its nothing but a spring and if it fails it won't kill the car. I drive almost 100 miles a day, though, and if it does ever fail it will be a giant hassle for me. If its a $50 or $100 part I'd probably just opt to change it to eliminate that possibility since it would cost me that much to get the car towed nearly 50 miles home when I lose the steering.

The high strength springs that assist in opening up my garage door have failed 3 times in 20 years.

Post by **benpineapple** » 17 Nov 2015, 08:05

Is the "serpentine belt tensioner" also referred to as the "idle tensioner"? I've heard both used, now I'm wondering if they're synonymous.

Post by **Clockboy** » 17 Nov 2015, 08:40

I would guess the springs on the garage door are subjected to much greater stress than the serpentine belt. It basically sits there and moves very little. The garage door springs are stressed every time it is opened and my guess is that if they really wanted to make springs that would outlast the door they could. If the guys that have seen and worked on multiple 200k cars have never seen it there is very little chance of it happening. I would take the money and invest it in AAA - there is a much higher probability that something else could go wrong and then you are covered. Of course if your tensioner breaks forget I said anything.

Post by **98v70dad** » 17 Nov 2015, 09:16

I'm not arguing the point, I was just looking for some information. I agree that the consequences of a failure are no real big deal. But muscling a car home 50 miles from work with the power steering out in 6 lanes of 70 mph rush hour traffic is not something I want to do. I've lost power steering before in another car and it was all I could do to get the car off the road and parked.

Torsion springs can and do fail just like everything else. I was trying to get a sense of how often people see them fail on these cars. So far two people have told me they've never seen one

Post by **cn90** » 17 Nov 2015, 09:19

For my 1998 S70, I replace my TB every 100K, not 70K.

The mechanical tensioner lasts a long time, all you need to replace is the 2 pulleys for the serp belt. Info below:

https://www.matthewsvolvosite.com/forums ... hp?t=53722

Post by **erikv11** » 17 Nov 2015, 09:55

I've never seen or heard of a spring fail on the serp tensioner.

I have, however, read of just a few actual failures of the serp belt pulleys. Never seen one but read about a couple. I have read about far more replacements of the serp pulleys than actual failures; it's not a bad way to spend a a Saturday afternoon when everything else is already fixed on the car.

Post by **mecheng** » 17 Nov 2015, 19:25

If you insist go ahead, but like I said the other posters have stated, the spring is very lightly loaded. If you do replace it get an original one. There are a lot of other parts that can leave you stranded and fail often, serp tensioner is not one of them