Replacement interval for accessory and timing belt tensioner and pulleys?

Post by **FireFox31** » 04 Jul 2023, 12:28

Hello, what's the recommended replacement interval for up-to-1998 accessory and timing belt tensioners and pulleys? Is it recommended to replace bolts such as the idler pulley bolt (on which the idler rolls)?

My 1998 V70 T5M has 178k miles and was always serviced by a dealer or competent tech but I don't have service records. It sat unused for the last six years. I'm preparing to replace the timing and accessory belt so would like to know how much other hardware should be replaced. Thanks.

For my car, I'm seeing the following part numbers and prices at FCP:
Accessory tensioner - 1275380 - $62 INA
Accessory tensioner pulley - 272136 - $33 INA
Accessory idler pulley - 9146139 - $43 INA
Timing tensioner - 9146693 - $103 Volvo
Timing tensioner pulley - 9135036 - $68 INA
Timing idler pulley - 8630590 - $25 INA

Post by **wizechatmgr** » 04 Jul 2023, 14:47

FireFox31 wrote: ↑04 Jul 2023, 12:28 Hello, what's the recommended replacement interval for up-to-1998 accessory and timing belt tensioners and pulleys? Is it recommended to replace bolts such as the idler pulley bolt (on which the idler rolls)?

My 1998 V70 T5M has 178k miles and was always serviced by a dealer or competent tech but I don't have service records. It sat unused for the last six years. I'm preparing to replace the timing and accessory belt so would like to know how much other hardware should be replaced. Thanks.

For my car, I'm seeing the following part numbers and prices at FCP:
Accessory tensioner - 1275380 - $62 INA
Accessory tensioner pulley - 272136 - $33 INA
Accessory idler pulley - 9146139 - $43 INA
Timing tensioner - 9146693 - $103 Volvo
Timing tensioner pulley - 9135036 - $68 INA
Timing idler pulley - 8630590 - $25 INA

Generally speaking it's recommended to replace them at the same interval as the timing belt. Most people can get away with going far longer - until they can't, and bad things tend to happen that cannot be easily undone short of tearing the head off to send it out to the machine shop.

This becomes one of those spend now or spend later type debates.

V50M66 · Post by **V50M66** » 04 Jul 2023, 15:14

Agreed with above - do all of it. Not worth risking your motor over. Do both belts, both tensioners, bolt idlers, and replace the water pump using new bolts. It’s also a good time to do cam seals while you have it apart.

Post by **scot850** » 04 Jul 2023, 15:49

On a time basis for a 98 it should be coming up for a 3rd timing belt change in it's life assuming an 8 year cycle. Normally Volvo recommends changing the water pump every 2nd timing belt change. As you don't have the records, you don't know if the pump was swapped at the last change or not, and with what brand of pump. You may be able to tell if you can get a mirror down to the pump with the TB belt cover off to see if it is a Volvo or aftermarket. If it is an Aisin, was it done last time? Who knows. Do you take a chance and believe it is good and run until the next belt change. V50M66 makes a good point. Do you take the risk or for the price of a pump do you take a chance on you motor?

Only thing I disagree with is the need for new bolts. Some aftermarket brands may supply them if you decide to go with a brand other than Aisin or Volvo OE. I think Volvo OE come with the bolts, but you can ask that, but my last Aisin did not. For the difference in price to buy Volvo bolts (Aisin and I think Volvo/Aisin pumps) now use 25mm long bolts not the 30mm they used to be.

If your bolts are 30mm in the original pump you will need the shorter ones. Based on the pricing up here if the OE pump comes with bolts is works out about the same price as buying Volvo bolts and an Aisin pump without bolts!

I am not sure what the paranoia on the bolts is. On an 850, 5 of the holes are through holes to the outside world and only 2 are not and they bottom out at around 17mm. None of the bolt holes appeared to have been threaded though beyond about 17-20mm approx.

These bolts are not high torque or torque to yield bolts. I think there is some belief coolant can escape up the threads. If that is the case then there is a bigger issue as coolant should not be able to reach the threads. I did clean the threads and use Permatex thread sealant with PTFE which is good to +300F and well below 32F. However this was more as a thread locker issue than sealing the threads.

Neil.

Post by **FireFox31** » 04 Jul 2023, 18:00

Thanks. I'm primarily interested in the accessory tensioner and pulley. Are they as critical as timing components? They're easily accessible, making me think I could swap them out only when I hear a problem. I will replace the accessory belt due to the age of the rubber.

I'm annoyed that I paid $137 for an accessory tensioner in 11/22 and it's now $62. I'm really just looking for an excuse to return it and not pay double.

I will also swap the coolant pump since I don't know its age. I use new Volvo coolant pump bolts because they have the special coating on the thread ends. It's easier than taking any chances.

Post by **abscate** » 04 Jul 2023, 18:27

On my original serpentine belt tensioner on all five of my Volvos at 175k, 255k, 255k, and 155k respectively

It’s a run to fail item , they will sing the song of death to warn you of their demise

I do serpentine belts every 60k and send them back to FreeCP

Post by **FireFox31** » 04 Jul 2023, 18:46

Thanks, that's what I was hoping to hear. I think this T5M has been treated well, maybe even had the accessory parts replaced at its first timing belt change. I'll replace only the belt this time.

V50M66 wrote: ↑04 Jul 2023, 15:14 It’s also a good time to do cam seals while you have it apart.

I didn't do this on my 2000 and I think it's the source of a huge leak. My other 2000 has even worse leaking so I'll replace this proactively. Heck, I might as well swap it on the 1998 even though I don't see a leak... yet. I've got to research the job first though...

Post by **abscate** » 04 Jul 2023, 18:52

Really easy on the -1999 prior to VVT. Just pop pulleys and put seals in. If you are doing the belt do all four seals

Send that overpriced tensioner back

V50M66 · Post by **V50M66** » 04 Jul 2023, 23:09

My serpentine belt tensioner was absolutely cooked at 170k. I'd do it. Not worth risking the engine over a hundred bucks or so.

Doing just the timing belt is a HORRIBLE idea. Do it once, do it right. If it's coming that far apart, why cheap out?

Post by **erikv11** » 04 Jul 2023, 23:23

Serp belt tensioner bad? Haven't seen that on a P80. Its pulley gets dry and I have both re-greased and replaced that item, the difference is in the effort for the most part, but never the serp tensioner. Regarding the pulley you can easily pull the belt give it a spin, if it freewheels then consider one of the maintenance options.