Wavey

87 S4 Auto Euro.

Hi all,
My TB was replaced 12-18 months ago just before I bought my car and I have just completed the WP replacement using a Kempf tool to set TB tension.
I brought the car for a spirited drive and the tension light came on at high revs.
I have taken off the right cam cover to recheck the belt and the tension is exactly where I left it.
I set the belt so that the tool pointer is at the tight side of the window on the tool.


Should I tighten a little more to overcome any inaccuracy in the tension warning mechanism?
Or do nothing and accept the warning light as a feature of spirited driving? (I have read post suggesting this on my year of S4)

I should I add that I did strip and clean the tensioner when the WP was out.

Many thanks.
Wavey.

FredR

First of all are you sure you set the tension with No1 cylinder on its firing stroke [not No6] at TDC? - this is critical to accurate results.

PorKen

Wavey

I followed the tool instructions. Tension was set when both right cam sprocket notch and HB 0deg markers lined up with fixed pointers. I think this means no.1 at BTDC?
Does the engine need to be in this position for a check of the tension also?

FredR

Based on your description you would have been at TDC on No1 cylinder. Having set the tension one should then rotate the motor using the starter motor and then check it again. All checks should be carried out in this position with No1 on its firing stroke. If set on No6 it wil generate a false tension setting.

There is also a note in the instructions to ensure the tool is clean and lubricated the latter correctly achieved by dabbing a couple of drops of sewing machine oil into the pivot point.

Spurious alarm events do occur but they rarely happen. If there is a genuine alarm condition the alarm will not go away by pullung the stalk and resetting it - the alarm will repeat. If you get regular alarms then something should be considered to be wrong and will need investigating. Maybe the system is settling down after your recent intervention?

ROG100

New Tool Ken? You moving to the dark side?

Mrmerlin

One thing to consider since you removed the tensioner and installed it ,
it has found a new position.
NOTE it will walk itself into its running position after a few heat cycles.

When I install the tensioner I press on the roller as if it was in the loaded position,
this will preposition the tensioner against the bolt shanks,
Then tighten the bolts while it in this pre positioned spot.
so the tensioner should not move much after you have tightened the bolts.

That said I use Hondabond on the tensioner gasket,
and fill the tensioner with STP oil treatment from a visene bottle,
so I dont blow the inner sealing ring off the boot
fill from the hole closest to the right fender.

PorKen

I believe the OP is referring to a Kempf tool

Wavey

Apologies Ken. I thought this was your tool.
I bought at the same time as one of your bump sticks.
Thread title corrected.

mj1pate

I suggest in addition to the advice from Stan, consider borrowing another Kemf tool. Please leave the project with satisfaction it has been done correctly

Myself

Hey there...if it helps...full set of 928 Workshop Manuals are posted at www.9porsche.com

GregBBRD

The belt light is extraordinarily accurate, from what we have seen.
The 1st sign of the belt needing tension generally comes after running the engine at higher rpms and then returning to lower rpms. Very common to have the light to come on, as you enter a freeway offramp.
The belt tension will, virtually invariably be between 3.0 and 3.2 "Porsche Belt Units", using the factory belt tension gauge.
I've never had nor used a Kempf tool.

To the OP, I'd suggest making sure the tensioner is full of oil. (Lack of oil can trigger false belt warning light.)
If the tensioner is full an everything looks normal, tension the belt 1/3 of a turn (two flats on the bolt) and tighten the locknut.
This should solve the belt tension light coming on and "get" the belt somewhere under the desired 5.0 setting.
If it does not, further investigation should be undertaken.

ador117

Bonjour,
I have been using the Kempf tool since 2011 and never get the light on. I rig to the max tension on the Kempf tool.
when I finalized my engine few months ago I realized that it was a very simple tool… and not the right tool required by Porsche in the WSM…
this evening I will see if I can calibrate it with a simple method, just for you to be able to compare and for me to make sure it stay good years after years…
have a great day,

ador117

Wavey,
If you would like to know if your Kempf tool spring is the same than mine, I loaded my tool like that :

That way the tool indicate the same than when in place on the belt :


In order to achieve that, I had to suspend a load of 2,18kg or 4,80LBS.
That way you should be able to compare and see if your tool behave the same.
Raphaël