Brett Jenkins

Tbelt was changed about 20k miles ~3 years ago and retensioned 2x since then by PO.


After replacing my clutch master and slave, I reassembled everything under the dash, including the connections under the dead pedal. Evidently, the warning system wasn't fully plugged in because I have dash warnings at start up that I didn't realize weren't functioning. One of those is the tbelt tension warning, which started coming on during acceleration.

So, I pulled the covers and checked the tension with my kempf tool. The tension was past the 3/4 point of the measurent window toward the radiator side. I checked the tensioner wire connection and the various bits and pieces in the tbelt system and all looked good, but I still get the tbelt warning light on acceleration.

So, I pulled the covers again, as I was going to tighten the belt a bit. I figured I should refill the tensioner before I adjusted the tension. I pulled the two plugs and gravity fed the 90wt oil. Quite a bit went in, but none ever came out the overfill side. Eventually, quite a bit did come out from underneath the tensioner.

So, I suspect the inner seal(s) are shot and leaking and the tensioner is/was dry.

So, my question is, would this cause the tbelt warning on acceleration?

I already have the parts quote from Roger for porkensioner and tbelt and such, so I guess I know what I'll be doing this weekend. :-)

mark kibort

the tensoner light system is fickle. I finally gave up and pulled mine. by the way, they go off after about 2 min after they sense something. (i.e. mine is "open" and the light comes on after 2 min!)
There is a broken connection or bad connection somewhere in the system.sounds like you are on the tight side anyway. High rpm acceleration is just probably creating vibration that is causing the circuit to fail.

mk

Cosmo Kramer

Could be that the lack of damping from the tensioner is triggering the light. Fill the tensioner from the top hole and fill until oil comes out the bottom hole. A small syringe works well, just take it slow.

If the tensioner is leaking, just put on the PKtensioner and I would do a new belt, water pump and inspect the cam/crank gears WYAIT. The PKtensioner has instructions to disable the t belt warning light as it is no longer used.

Mike Frye

Not sure what you mean by this. You said it's "past the 3/4 point of the measurement window toward the radiator side". If you're leaning into the engine bay and you put the tool on there, then tilt it up so the tool is flat against the plate is the pointer closer to the front or rear of the car?

It almost sounds like you mean it's reading at 1/4 of the way up, which would be loose.

+1 on what Mark said, the delay is somewhere between 2 and 3 minutes, so if it happens while you're accellerating, it's detecting something before that. The 'tensioner' is actually a de-tensioner (TM- Jim Bailey ) so it really does it's work upon decel rather than acceleration, taking up the slack on that side of the belt.

If you've got the parts, I'd go for it and just replace all with new.

I've only had that light go on once or twice (right after initial setup) and it probably took about 2 years off my life.

heinrich

You need oil in there. If it isn't holding oil, start there and resolve that. A dry tensioner can seize (it wears the teflon coating inside away). Doubtful it is making the light come on UNLESS it has already screwed up in there to the extent that it is allowing so much flutter that you're in danger of a failed belt.

heinrich

I thought his description was actually refreshingly clear (to me) Mike

rixter

I had a similar issue happen with my 88, when low on fluid while engine is running the tensioner rocks back and forth setting off the light.. always reads correct when checking with engine off
from what you're saying, the gasket is pinched at the bottom, you'll need to go back in and replace the gasket to fix this problem

Brett Jenkins

Yes, when the tool is twisted up, the measurement window points toward the engine and toward the radiator. If the measurement is closer to the engine, it is loose, and closer to the radiator it is tight, right?


I suppose I could pull the tensioner and rebuild it, but at 20k miles and 3 years on the belt and water pump, I might as well just replace it all and throw in a porkensioner while I'm at it.

Mike Frye

Sorry, couldn't picture it in my head. I've never heard it described that way. Carry on.

PorKen

The [BELT. TEN. @] light has a 3-minute delay at startup only. While running, there is no delay.

(I think the delay is to stop spurious warnings because the factory tensioner doesn't manage the belt tension well when the engine is dead cold.)



The OEM tensioner is a detensioner, but it's not about deceleration. The cupped Belleville bi-metal washers in the tensioner flatten out when they get hot, thus reducing how far they push the arm/pulley, reducing belt tension in an attempt to match engine expansion.

Mike Frye

I thought the spring on the arm was there to expand it slightly to take up the slack on decel, no?

cold_beer839

You are wise beyond your years Grasshopper.

I would do that exactly.

Rebuild the stock tensioner and put it on eBay and make some money back.

PorKen

No.

The spring is just for the tension light, it forces the arm away from the plunger if the tension is too low. No ground, light comes on. (Pre-85 don't have the spring.)

Mike Frye

Ah, looks like I need to buy a system I can understand, like that one I keep reading about on here designed by that mad scientist.