E60 (M54) Tensioner and Idler Pulley replacement
08-08-2017, 12:10 PM
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My Ride: E60 530i
Model Year: 2004
Engine: M54
E60 (M54) Tensioner and Idler Pulley replacement
I replaced 2 belt tensioners (AC and Serp.) and idler pulley in M54 last week to address motor humming noise when AC was ON and squeaky noise from Serp. belt area when AC was ON or OFF.
My 530i has M54 engine, so that Serp. belt tensioner is mechanical one not hydraulic. Over all, it was easier than I expected except the step to remove lower 13mm bolt of Serp belt tensioner. It was under tensioner itself, we have to use our hand/finger to get down there and feel the location of the bolt before inserting socket and extension to that bolt. It took me about 20 minutes to slowly undo that bolt.
AC belt tensioner and idler pulley were the easiest. One bolt each to the center of these 2 parts.
1) put car on ramp
2) remove under cover - the one toward to the front; 6 philips screws (3 on each side and 2 in back of the cover). These screws couldn't be remove from cover; just unscrew them to "lose" position
3) Use T60 torx bit to release tension of AC tensioner from under the car. Turn torx bit clockwise (don't need to much force) and take belt off
4) Undo center bolt of AC tensioner (16mm ?). It was not very tight. I got it undo with 3/8 wrench. Tensioner would then come right off. Please note the back side of AC tensioner has two pieces of "teeth" which would only mate onto the engine block in one way, not the other.
4) install new AC tensioner and tighten new center bolt. I could not find torque spec. so I tighten it as much as possible with 3/8 wrench. I could not fit an 1/2 wrench from bottom unless fan shroud is removed.
5) From top of the car, release tension of Serp. belt tensioner. Mechanical tensioner need a 16mm socket and turn it clockwise to remove belt.
6) 2 13mm bolts held Serp. belt tensioner in place. I use 3/8 wrench with extension to get them off. Serp. belt tensioner could only come out from bottom of car between crankcase pulley and power steering pulley. I tried the top but blocked by coolant hose.
7) Idler pulley is between alternator and power steering pulley. It was held by T50 (I think). Torx bolt of this pulley is behind plastic cover. This pulley was quite tight but I had no problem to undo it with 3/8 wrench. 1/2 wrench was too big in that tight space.
8) Install new Serp. belt tensioner with 2 new 13mm bolts and new idler pulley. I tightened them as much as I could using 3/8 wrench.
9) Before putting serp. belt back on, turn new serp. belt tensioner clockwise and lock down tensioner with a nail or some sort. I used allen key and inserted it through the 2 holes of the tensioner. Then we would have 2 hands to put serp. belt back on.
10) Install AC belt
11) Install under car cover
12) start car to check belt install properly and then done
My 530i has M54 engine, so that Serp. belt tensioner is mechanical one not hydraulic. Over all, it was easier than I expected except the step to remove lower 13mm bolt of Serp belt tensioner. It was under tensioner itself, we have to use our hand/finger to get down there and feel the location of the bolt before inserting socket and extension to that bolt. It took me about 20 minutes to slowly undo that bolt.
AC belt tensioner and idler pulley were the easiest. One bolt each to the center of these 2 parts.
1) put car on ramp
2) remove under cover - the one toward to the front; 6 philips screws (3 on each side and 2 in back of the cover). These screws couldn't be remove from cover; just unscrew them to "lose" position
3) Use T60 torx bit to release tension of AC tensioner from under the car. Turn torx bit clockwise (don't need to much force) and take belt off
4) Undo center bolt of AC tensioner (16mm ?). It was not very tight. I got it undo with 3/8 wrench. Tensioner would then come right off. Please note the back side of AC tensioner has two pieces of "teeth" which would only mate onto the engine block in one way, not the other.
4) install new AC tensioner and tighten new center bolt. I could not find torque spec. so I tighten it as much as possible with 3/8 wrench. I could not fit an 1/2 wrench from bottom unless fan shroud is removed.
5) From top of the car, release tension of Serp. belt tensioner. Mechanical tensioner need a 16mm socket and turn it clockwise to remove belt.
6) 2 13mm bolts held Serp. belt tensioner in place. I use 3/8 wrench with extension to get them off. Serp. belt tensioner could only come out from bottom of car between crankcase pulley and power steering pulley. I tried the top but blocked by coolant hose.
7) Idler pulley is between alternator and power steering pulley. It was held by T50 (I think). Torx bolt of this pulley is behind plastic cover. This pulley was quite tight but I had no problem to undo it with 3/8 wrench. 1/2 wrench was too big in that tight space.
8) Install new Serp. belt tensioner with 2 new 13mm bolts and new idler pulley. I tightened them as much as I could using 3/8 wrench.
9) Before putting serp. belt back on, turn new serp. belt tensioner clockwise and lock down tensioner with a nail or some sort. I used allen key and inserted it through the 2 holes of the tensioner. Then we would have 2 hands to put serp. belt back on.
10) Install AC belt
11) Install under car cover
12) start car to check belt install properly and then done
08-08-2017, 04:18 PM
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My Ride: 530i
Model Year: 2004
Engine: M54
Nice job, agree with you on using the mechanical tensioner versus hydraulic. I've seen hydraulics fail early multiple times.