Michael Weinstein

I have owned my car for less than 1 week, and I have something weird going on. When I do a full out accelleration run, I get the 'belt tension' light coming on in 2nd gear. It only comes on in 2nd gear, and only when I am in the uppermost RPM range. Is this something I should be concerned about? I know how important timing belt health is to these cars. Any help would be appreciated.

Ed Ruiz

You did not say the year and model 928 you have. If it has 32 valves, then the timing belt is critical. If it has 16 valves, it may not be so critical. YMMV.

It sounds like your belt is just a bit loose. If it's less than 5 years old and has fewer than 60k miles, it may only need retentioning. Otherwise, replace it. I would also replace the water pump, roller bearings, bushings, and rebuild the tensioner.

Tony

hi

i would heed (sp) all warnings given to you regarding the timing belt..strange noises and importantly the light! The light ONLY tells you the belts tension is NOT sufficient enough to keep the warning system grounded..how loose it is, is anyones guess. What condition it or any of the pulleys or bushings are is even more of a guess. give your self peace of mind and check/replace it.

When i did my belt on my 87s4 i did a little experiment. I found that the belt tension light came on at a setting of 3.0 with the factory tool. The engine was obviously not running so a moving motor changes the dynamics of everthing. just FYI stuff i guess. If i were you i would pull the passenger side belt cover and atleast inspect the belt then retension it properly. DO NOT SIMPLY TIGHTEN THE BELT UNTIL THE WARNING GOES AWAY!!! BIG NO NO and often done by a few mechanics. The belt needs to be properly tensioned with the factory tool or the JAY KEMPFH after market tool (shameless plug)
check my web site for some info www.members.rennlist.com/v1uhoh/

Michael Weinstein

Thanks Guys,

I am looking into a factory tensioning tool right now (and some factory manuals). I guess that I'll just drive my other car until they come in.

Is there a procedure out there that someone has written already? I would like to check this out if one exists.

Thanks!

Michael Weinstein

BTW, I have a 1986.5 928S.

UBoatCommander

Michael,

This is typically what you will see when the belt needs attention. First it comes on at 6k, then if you keep driving it will come on at 5K, then 4K etc. Time to take a look at it. If it comes on while loafing down the freeway at 2K, then you've got an IMMEDIATE problem like a siezing waterpump or something (don't ask me how I know!) Like Ed said, when you replace the belt, replace all moving parts including water pump, bearings and rebuild the tensioner.

UBC

Jay Wellwood

Here is a general list of items needed to replace the Tbelt...

Item No. Price
Timing Belt* 1 $44.00
Flywheel Locking Tool 1 $16.00
Thermostat 1 $25.00
Thermostat O-ring 1 -
Tensioner Boot* 1 $6.00
Tensioner Boot Clamp* 1 $5.50
Tensioner Gasket* 1 $12.00
Tensioner Inner Seal* 2
Tensioner Large Roller* 1 $55.00
Tensioner Idler Bushing*1 $1.70
Texaco Dexcool 2
Water Pump* 1 $119.00
Water Pump Gasket* 1 $1.65
Belt Tension Tool 1 $59.00
Accessory Belts 3 -

Thom1

Michael,

I hope and imagine that you are reading other timing belt posts. See Timing Belt Gulp ...

I would park the car until you check the belt tension. If it slips, you could be in for a $6-8K valve job.