Not a Merc but a Porsche (after some help)

[coventryslk]

Afternoon

Bought a tidy boxster 986 last year very very cheap but decent with a nominal sum money left to me by a relative.

A couple of weeks ago I changed the 3 drive belt pulleys for new.... went for a short drive and a massive rumble after the initial satisfaction of a nice smooth sounding engine.

Removed and returned them as the bearings looked cheapo compared to the original FAG one in the old pulleys.

I then went a purchased 3 new FAG bearings and had the old ones pressed out and new ones into the old pulleys (felt great at this time as with refund of other pulleys this route cost £13).

Refitted, threadlock, torqued up bolts (refitted old drive belt.... as will pick one up soon).

Again, car sounded nice. Went for a drive on Friday lunchtime and on the way back home the rumble began again.... Time for strip down number 3.

Would anyone on here have any knowledge or guidance of what is going wrong? The tensioner pulley is on a lever arm from the self tensioning mechanism and could this be over tensioning the belt? Or is it as simple as the old belt causing this issue above?

I'll order 3 new bearings tomorrow and refit when I figure out whats going wrong

 

[Uncle Benz]

Did any of the pulleys feel rough when you took them back off? I’ve changed water pumps, alternators and air conditioning compressors on these cars, all for rumbling. Porsches, sadly, are made of the cheapest possible parts.

 

[coventryslk]

Did any of the pulleys feel rough when you took them back off? I’ve changed water pumps, alternators and air conditioning compressors on these cars, all for rumbling. Porsches, sadly, are made of the cheapest possible parts.

Thanks for the reply I totally agree that these cars are made with cheap parts. The things you can easily see such as a four piston calipers are great then you look further... front and rear macpherson struts... wheres the front double wish bones??? Door membrane made from crap foam. I could go on....

I used a stethoscope to trace the noise. Tensioner pulley was bad each time. The upper and lower had noise. The new tensioner i got from a porsche parts specialist, the sleeve nut had expanded and was jammed to the inner race of the new pulley bearing.

Waterpump was OK as was the alternator and power steering and aircon, just a bit perplexed. Must be excessive side loading on those new bearings. I'm off work this week and will take it apart early tomorrow morning and also order some new bearings....and pick up a new belt

I'll check and double check. Whats the likely hood of crank pulley being an issue?

I probably should have kept looking for a W208 Convertible

 

[Uncle Benz]

Look carefully to see if the alternator has a freewheel pulley on it. Do a bit of googling to see what you are looking for. A lot of modern cars have them, but I can’t remember if these Porsches do. The freewheel pulleys often seize internally, and when that happens they overload the tensioner pulley. Not saying this is your problem, but it’s a possibility

 

[Uncle Benz]

Quick google suggests a lot of 986 have them fitted. You can feel if it’s working by holding the pulley firmly (with the belt off) and twisting it rapidly too and fro. You can feel it freewheel in one direction. If it has seized it won’t freewheel

 

[Uncle Benz]

Found this which shows the freewheeling type…

2001 free wheeling alternator pulley - 986 Forum - The Community for Porsche Boxster & Cayman Owners

For those that have changed the alternator pulley, if you can help. I cracked open the panel behind the seats to examine the belt and pulleys. The

986forum.com

 

[coventryslk]

Quick google suggests a lot of 986 have them fitted. You can feel if it’s working by holding the pulley firmly (with the belt off) and twisting it rapidly too and fro. You can feel it freewheel in one direction. If it has seized it won’t freewheel

Thank you, I'll be checking that!
If that's the problem there's a place by me that will rebuild the bosch unit for £120

 

[coventryslk]

Found this which shows the freewheeling type…

2001 free wheeling alternator pulley - 986 Forum - The Community for Porsche Boxster & Cayman Owners

For those that have changed the alternator pulley, if you can help. I cracked open the panel behind the seats to examine the belt and pulleys. The

986forum.com

Just had a quick read, I'm not sure if I've the freewheeling one....but regardless if its not ill still double check it rotates freely

 

[Uncle Benz]

If it’s the pulley they’re about £25, but you need a special tool to unscrew it

 

[Uncle Benz]

Just had a quick read, I'm not sure if I've the freewheeling one....but regardless if its not ill still double check it rotates freely

If that picture is your car you don’t have the freewheel type

 

[coventryslk]

If that picture is your car you don’t have the freewheel type

Yes its my car, took the photo before I replaced the pulleys first time round.
I will check the power steering pump again for free rotation and also the aircon pump.

 

[Uncle Benz]

Yes its my car, took the photo before I replaced the pulleys first time round.
I will check the power steering pump again for free rotation and also the aircon pump.

Well that’s my theory out the window then! Good luck, keep us posted

 

[coventryslk]

Air con pump is freewheeling?

 

[LostKiwi]

Aircon pump has a magnetic clutch. Once the clutch is energised it drives the compressor.

 

[coventryslk]

Aircon pump has a magnetic clutch. Once the clutch is energised it drives the compressor.

Thats what I was trying to put, was late

 

[LostKiwi]

Easy to test the compressor - simply turn the A/C off. If noise goes the compressor is noisy (clutch is deenergised so pulley freewheels).
If it's noisy when on but not when off the A/C compressor is the issue.
If it's noisy when off but not when on the magnetic clutch is the issue.

 

[coventryslk]

Easy to test the compressor - simply turn the A/C off. If noise goes the compressor is noisy (clutch is deenergised so pulley freewheels).
If it's noisy when on but not when off the A/C compressor is the issue.
If it's noisy when off but not when on the magnetic clutch is the issue.

Was up early this morning at 5am, did some DIY then went to a waterfall in Wales instead of doing the Boxster as got week off.. Will be up early tomorrow and going to go over it with your tips.

Had a thought that the crank pulley possibly be out of true as the belt follows from the tensioner pulley. I saw something where it sits in the locating key it can jump off it causing some distortion.

Thanks for your advice though, I will be using it to try solve this issue.

I saw a lovely low mileage 208CLK for £2k on autotrader last month... I should have waited

 

[coventryslk]

I have tested the air con pump as advised, no noise with it either turned on or off. It turns ok without the belt.

No noise/rumble/vibration from the alternator, it too turns ok and no play without belt

Crank - no rumble from that area, I put the stethoscope probe down behind the pulley.

Power steering, seems ok too. Slight weep at the bottom, turns ok without the belt, no play.

Tensioner bearing i replaced is rumbling bad as expected but it either be a dodgy bearing or a symptom. I've new bearings to put in. Original being FAG 800919b and replaced with FAG 6203-2RSR C3 which I believe to be the correct deep groove items and checked with the bearing supplier for new/old part numbers.

Belt looks like its been dragging, its not that old, 6 grooves look like been rubbing and compared them to a Merc belt I bought years ago but never fitted.

I'll have a cup of coffee and a think and go back outside in the sunshine.

 

[coventryslk]

Just noticed some coolant below the waterpump.... lots of play. That will need to be changed!

 

[LostKiwi]

Just noticed some coolant below the waterpump.... lots of play. That will need to be changed!

And there we have the smoking gun (or dripping pump). That will be the issue.