Replacing the belt tensioner

DeutschRennfahrer · 03-13-2018, 10:30 PM

Has anyone here had to do this? It doesn't look like there is much room to access the belt without removing radiator components. Any help/guidance is much appreciated.

StickMon · 03-14-2018, 12:08 AM

Easy peasey.
Just take the fan out. Plenty of room.
Let us know if you need help on "just take the fan out".

DeutschRennfahrer · 03-14-2018, 08:22 AM

Haha well I'm glad to hear it's easy. Would there happen to be a write up or video somewhere that shows me exactly how easy it is?

StickMon · 03-14-2018, 07:20 PM

Don't know off-hand for the 3.0. This thread came up in a search for "belt tensioner":
http://www.zpost.com/forums/showthread.php?t=1282597

Efthreeoh · 03-18-2018, 07:23 AM

I've not yet done the belt tensioner on my E86 N52, but I have done it on the N52 in my E90. It's an easy DIY. I'm a 40-year long DIY'er. Remember the bolt that holds the tensioner to the engine block is aluminum and is a torque-to-yield bolt, so it needs to be torqued correctly. Several on-line companies sell a kit with the belt, bolt, tensioner and idler pulley. ECS and Turner are two such sources.

The E86 seems to be a bit tighter up front than the E90. Removing the cooling fan usually frees up enough space. I haven't removed the cooling fan on the E86, but looking at RealOEM.com it looks pretty much like every other BMW cooling fan. There is an electrical connection, a hold down screw and a plastic rivet that holds the fan in place once the fan is slotted into the tabs at the bottom of the radiator.

Once the fan is out, you need a T60 Torx socket and a breaker bar to release the tensioner to remove the belt. You need a torque wrench to properly torque the new aluminum bolt.

It's simply:
- loosen the tensioner. There is a set of holes that line up where you can place a small diameter pin (such as a screw) to hold the tensioner open
- remove the belt (keep track of the routing - make a drawing)
- remove the idler pulley
- then unbolt the tensioner
- Install the new tensioner (it comes open with a pin in place). Torque the new bolt correctly to spec.
- replace the idler pulley
- route the new belt
- and release the tensioner

Here is the E90 procedure for the N52:

http://www.e90post.com/forums/showth...ight=Tensioner

03-13-2018, 10:30 PM	#1
DeutschRennfahrer Private First Class 39 Rep 115 Posts Drives: 2006 Z4 3.0i - Saphire Black Join Date: Jan 2015 Location: Nashville, TN iTrader: (0)	Replacing the belt tensioner Has anyone here had to do this? It doesn't look like there is much room to access the belt without removing radiator components. Any help/guidance is much appreciated.
	Appreciate 0 Tweet Quote

03-14-2018, 12:08 AM	#2
StickMon My other car is on Mars 636 Rep 3,124 Posts Drives: 2006 MR Join Date: Feb 2011 Location: Lo-Cal iTrader: (1)	Easy peasey. Just take the fan out. Plenty of room. Let us know if you need help on "just take the fan out". __________________ Warning: May contain traces of nuts.
	Appreciate 0 Quote

03-14-2018, 08:22 AM	#3
DeutschRennfahrer Private First Class 39 Rep 115 Posts Drives: 2006 Z4 3.0i - Saphire Black Join Date: Jan 2015 Location: Nashville, TN iTrader: (0)	Haha well I'm glad to hear it's easy. Would there happen to be a write up or video somewhere that shows me exactly how easy it is?
	Appreciate 0 Quote

03-14-2018, 07:20 PM	#4
StickMon My other car is on Mars 636 Rep 3,124 Posts Drives: 2006 MR Join Date: Feb 2011 Location: Lo-Cal iTrader: (1)	Don't know off-hand for the 3.0. This thread came up in a search for "belt tensioner": http://www.zpost.com/forums/showthread.php?t=1282597 __________________ Warning: May contain traces of nuts.
	Appreciate 0 Quote

03-18-2018, 07:23 AM	#5
Efthreeoh General 17294 Rep 18,725 Posts Drives: The E90 + Z4 Coupe & Z3 R'ster Join Date: May 2012 Location: Virginia iTrader: (0)	I've not yet done the belt tensioner on my E86 N52, but I have done it on the N52 in my E90. It's an easy DIY. I'm a 40-year long DIY'er. Remember the bolt that holds the tensioner to the engine block is aluminum and is a torque-to-yield bolt, so it needs to be torqued correctly. Several on-line companies sell a kit with the belt, bolt, tensioner and idler pulley. ECS and Turner are two such sources. The E86 seems to be a bit tighter up front than the E90. Removing the cooling fan usually frees up enough space. I haven't removed the cooling fan on the E86, but looking at RealOEM.com it looks pretty much like every other BMW cooling fan. There is an electrical connection, a hold down screw and a plastic rivet that holds the fan in place once the fan is slotted into the tabs at the bottom of the radiator. Once the fan is out, you need a T60 Torx socket and a breaker bar to release the tensioner to remove the belt. You need a torque wrench to properly torque the new aluminum bolt. It's simply: - loosen the tensioner. There is a set of holes that line up where you can place a small diameter pin (such as a screw) to hold the tensioner open - remove the belt (keep track of the routing - make a drawing) - remove the idler pulley - then unbolt the tensioner - Install the new tensioner (it comes open with a pin in place). Torque the new bolt correctly to spec. - replace the idler pulley - route the new belt - and release the tensioner Here is the E90 procedure for the N52: http://www.e90post.com/forums/showth...ight=Tensioner __________________ A manual transmission can be set to "comfort", "sport", and "track" modes simply by the technique and speed at which you shift it; it doesn't need "modes", modes are for manumatics that try to behave like a real 3-pedal manual transmission. If you can money-shift it, it's a manual transmission. "Yeah, but NO ONE puts an automatic trans shift knob on a manual transmission."
	Appreciate 0 Quote