OK I have an '87 Auto. It seems that when I put the car in 2n "step on it" and wind it out -but not too high- the belt t tensioner light appears, as well as the ! light. When I turn the car off and restart it goes away.

Last May my Porsche mechanic (drives an '85 standard) replaced the timing belt. Each time this has happened (2) car has continued to perform as well as it always has. Should I explore this further? Seems to only happen when I really nail the throttle.

Thanks for your insight,

Josh

 

Yes you need to know what is causing this as you are a split second away from a trashed engine.

You could be really lucky and it is only a warning circuit issue but I went through my timing belt setting, tracking, idles, bushings, and every other part of the belt system before I could convince myself that it was a warning circuit problem.

 

Had same situation in mine.
Check you belt tension, mine had developed just enough laxity that it would trigger tension light in higher RPM shifts.

 

Have you reset the belt tension since the belt was replaced? After the belt is replaced, tension should be checked after about 1,000 miles. (New belts stretch just enough to make this necessary.) Hopefully, tightening the belt up to spec is all that's needed.

 

You do need to actually test for tension though, you can't just add tension without knowing where you are at.

Likely its just that initial stretch since it is pretty new - your mechanic should have known that you would need a retension though...?

Whenever you see the tension light you need to be really worried and get it checked post haste!

Alan

 

the other caveat is that if you had a rebuilt water pump installed ,
it could have a slipping bearing housing,
this will reduce the tension on the belt and eventually cause damage to the block from the impeller hitting it

 

Had the same with my 86 for many months, rechecked and adjusted the tension and no issues since for 3 months including a track day.

 

Josh, if you have not done it before, get a Kempf tool.
It's low cost and comes with a very helpful set of directions. Very easy process and helped me develop a comfort level with the system itself.

Good news is that your warning light does function and likely saved you from a very bad situation.

 

You could also get a PKensioner and forget about your tension light.

 

^^^^ and be oblivious when the waterpump bearing is starting to go.....that will take out the belt for sure and you'll have fraction of the warning time before it lets go.

+1 to find out why the belt is loose at high RPMs.

 

^^^^^^^^^No. You still do your normal maintenance and belt replacement schedule but you don't have a 40 year old design that only tensions in one direction. Everything has a chance of random failure but putting a better design in helps make things better. Keeping what was there, that works with constant monitoring is not as good as putting something in that works with just doing regular maintenance.
If your water pump bearings are failing you bought a cheap pump or don't check things like you should.

 

Better design? I don't know about that. When a key warning feature is removed from a system, I wouldn't call that a beter design. The warning system saved my engine and I wouldn't go without it.

 

I seem to remember we have been down this road before. I am glad your light is working, best get to the bottom of it.

 

My warning light does the same thing after very hard acceleration with abrupt high rev upshifts. Brand new belt, new Lasso pump, all new rollers, rebuilt tensioner, etc. After the first time the light came on I tightened the tensioning bolt 1/4 turn. About a month later drove it down to KLVA's to check the tension. It was just barely outside the window (over tight). Left it there as the Conti belt will likely stretch. I have read all there is to read about Conti belts stretching. Not convinced the Conti belt can be blamed for the light coming on under hard acceleration. Normal driving does not cause the light to come on. Kevin and I think it's a very brief fault in the warning circuit, during the hard upshift. The belt tracks well centered on the cam gears, rollers, etc. Really strange.

 

OK, let's look at it this way: You've go a system made up of various components (belt, pulleys, wiring), which is occasionally misbehaving and giving you a warning. Most of the components are new or known to be good: Pump, rollers, tensioner. One component is known to be an issue: the Conti belt. And one set of components is a complete unknown: the alarm wiring.

So, in attacking this problem, do you ignore the known suspect (the belt) and try to eliminate the unknown (the wiring)? Or do you first address the known-suspect component?

This is sort of like asking a cop who they are going to pull in first for some dark deed: the guy with motive, opportunity and no alibi? Or the next guy walking down the street?

I learned long ago that if you leave known-flaky components in place because you think they are OK, then they will bite you in the *** every time. Ditch the Conti belt, set the tension properly, and if the problem persists then worry about the wiring.