Accessory Belt Tensioner - Pulley or Assembly?

Post by **cn90** » 23 Jan 2023, 11:38

Search forum but serp belt length has to do with PS pump pulley diameter...

a3inverter · Post by **a3inverter** » 23 Jan 2023, 18:28

Based on feedback from FCP, what I need is the Continental 6DK1825.

Some specs (from the Rockauto website)

6DK1841 (the one listed as being for the 2006 V70 with chassis numbers below a certain value- mentioned earlier in this thread)
6 ribs
Length = 72.48"
Width = 0.81"

6DK1825 (the one suggested by FCP)
6 ribs
Length = 71.85"
Width = 0.81"

Post by **firstv70volvo** » 23 Jan 2023, 20:46

a3inverter wrote: ↑23 Jan 2023, 18:28 Based on feedback from FCP, what I need is the Continental 6DK1825.

Some specs (from the Rockauto website)

6DK1841 (the one listed as being for the 2006 V70 with chassis numbers below a certain value- mentioned earlier in this thread)
6 ribs
Length = 72.48"
Width = 0.81"

6DK1825 (the one suggested by FCP)
6 ribs
Length = 71.85"
Width = 0.81"

It would be helpful for FCP to show both belt options for the 2006 model year since this is when the belt length mid-year changed happened based on the chassis VIN number. A 16mm or 0.63 inch difference in belt length is not trivial, I'm still wondering if it's an accessory pulley diameter change or if it's just more of a tension on the tensioner change that was the desired change. The Rockauto specs are helpful to sort the belt length differences out.

Post by **cn90** » 24 Jan 2023, 11:48

- Measure PS pump pulley diameter, then search forum for correct belt length.

This has been discussed here before...

Oly850 · Post by **Oly850** » 24 Jan 2023, 12:10

I did this job two days go with my son on his V70 while changing the timing belt. Definitely the accessory tensioner is flat and wears slightly with grooves, but how much will you save just replacing the pulley? We just ordered the whole shebang.

Post by **firstv70volvo** » 24 Jan 2023, 12:44

cn90 wrote: ↑24 Jan 2023, 11:48 - Measure PS pump pulley diameter, then search forum for correct belt length.

This has been discussed here before...

It does look like it's the PS pulley diameter that changed at the same chassis number split as the belt length, there are two different part numbers for the power steering pump at the same chassis number split. Smaller diameter pulley also used by the V70R model.

this is all I could find on the PS pulley diameter, 5 1/8 inch but I don't know if this the larger or smaller diameter PS pulley, I think he's referring to the larger diameter pulley but not100% sure
viewtopic.php?p=613704&hilit=power+stee ... er#p613704

later PS pump with the same chassis split number as the different belt lengths
https://www.volvopartswebstore.com/prod ... 50560.html

Post by **cn90** » 24 Jan 2023, 13:01

The lifespan of pulley ball bearings is about 100K-120K miles

The assembly has a big torsional spring inside that rarely breaks before 200K.

If car is more than 200K, the replace the tensioner assembly.

For the serp belt...best is to measure the PS pump pulley diameter, never know P.O. replaced the PS pump with sth else.

Post by **erikv11** » 24 Jan 2023, 16:21

The usual point should be made that as (almost) always on car repairs, mileage is not a very useful indicator here or "rule of thumb" regarding lifespan of the tensioner pulley. Depends on highway or city miles, climate, etc.

Some may last 80k, some may go to 220k. Moreover, even if you're looking for a "rule of thumb," based on all the forum posts it is at least closer to 150k ... however speculating only causes problems and misconceptions and to my knowledge no one has collected MTBF data on this part.

OP already knows the pulley bearings are aged in this case, that is the thing to look for here (see first post in thread).

Post by **firstv70volvo** » 24 Jan 2023, 18:28

a3inverter wrote: ↑23 Jan 2023, 18:28 Based on feedback from FCP, what I need is the Continental 6DK1825.

Some specs (from the Rockauto website)

6DK1841 (the one listed as being for the 2006 V70 with chassis numbers below a certain value- mentioned earlier in this thread)
6 ribs
Length = 72.48"
Width = 0.81"

6DK1825 (the one suggested by FCP)
6 ribs
Length = 71.85"
Width = 0.81"

So it does look like the PS pump pulley size changed and why the difference in belt lengths. As CN90 mentioned, measure the PS pulley diameter of your PS pulley to make sure it wasn't swapped out with a different size in the past. I just went out and measured the diameter on my 2001 V70 and it measured ~5 5/8 in. From the other post I found Dave0304XC measured 5 1/8 so I believe those are the two different pulley sizes. With your chassis number and the shorter belt length belt recommended I expect your pulley size will be the smaller diameter 5 1/8 inch pulley. I'd be curious to know what size PS pulley your car has.

Post by **cn90** » 25 Jan 2023, 05:58

Mileage is a very useful indicator in car repair.

Of course everyone drives differently...city, city-hwy mix, vs mostly highway. But to me, mileage is a very useful indicator.

In a perfect world, you measure number of revolutions (# cycles) and figure out how many millions revolutions before changing belt.

In the absence of that data, most owners manual use odometer reading, which is more practical.

Accessory Belt Tensioner - Pulley or Assembly?

Re: Accessory Belt Tensioner - Pulley or Assembly?