On my '94 945T, with 70K miles, the most of the panel warning lights light up per usual during starting, but stayed on this a.m. while my wife drove the car a few miles home from work.

The FAQ has some tips on this...bad alternator wiring, especially the "exciter current" wire that goes into the back of the alternator (if it is grounded, it will 'appear' as if the alternator is not charging). Or, it could be the alternator is, in fact, out of order.

I would appreciate any war stories/troubleshooting tips. Thanks!

--Greg

Finally got it all taken care of this a.m. Spending time with the A/C compressor and its many, many bolts trying to loosen the pivot points was very time consuming, but it all worked out. (Still don't know exactly which ones "worked," and if this isn't a reason to buy a manual, I don't know what is!)

I have a timing belt change coming up in the future, so I will look to change all the belts (except the alternator belt) at that time.

I wondered, given that I have dual-belt pulleys on both the alternator and the A/C compressor, if I should use two alternator belts, but this is not indicated on the belt diagram in the Owner's Manual.

Thanks all for the advice.

--G.

Got my wife to let me look at the car: snapped alternator belt!

I wonder if that's typical at 70K?

--G.

Dear Greg,

Good p.m. and may this find you well. An alternator belt should last more than 70K, unless it is (a) 11 years old; (b) has been too loose or (c) has been very much too tight.

If the belt is the original, it may simply have dry-rotted from age. Do you have maintenance records, which show when the belt was last changed

Being too loose allows the belt to slip, which generates heat, which softens the belt and leads to failure. Being too tight over-stresses the belt. Generally, being a bit too tight is better than being a bit too loose.

Check the alternator bushings (these are the three round rubber grommets through which the alternator mounting bolts pass; two at the top, one at the bottom of the mounting). The bushings should be round. If the bushings are egg-shaped, the belt has been over-tight.

The bushings provide vibration insulation and keep the alternator's axis exactly parallel with that of the crankshaft. That means the drive belt is perfectly perpendicular to the axis of the generator's shaft and to the axis of the crankshaft. This is how it should be. When the bushings are distorted, the alternator shifts, and that puts strain on the belt, one side of which is pressed against the inner surface of the pulley. That accelerates wear.

Replacement bushings can be bought from www.fcpgroton.com. With only 70K, get the Urethane bushings. They're more costly than the rubber originals, but will last a very long time.

When you re-install the belt, inspect the surfaces of the alternator pulley and the crank pulley (the harmonic balancer) to see if there's any black rubber residue. If there is, that's evidence of belt over-heating. Remove the rubber residue with paint thinner or methy ethyl ketone (MEK, chemical cousin of acetone). Wear gloves while handling these solvents. Dry thoroughly before installing the new belt.

Hope this helps.

Yours faithfully,

spook

Thanks for the good advice...belt pulleys and mounting bushings are all in great shape.

Here's the problem...the replacement belt I bought is TOO BIG!

I bought a Gates 7400, which according to its website (and of course the guy at NAPA) is the right one for a '94 B230FT. Well, even with the tensioner "let all the way out" (absolutely at the end of the adjustment screw), the belt is loose.

It's obviously the wrong spec. According to the belt package, it is 1030mm long (40-5/8").

Am I doing something wrong?

Hmmm...on further inspection...looks like I was thinking of the wrong pulley. I didn't get a look at the belt before it snapped, but now it seems clear it should be attached to the large main pulley. This means removing the AC belt...? Which means removing the alternator? More of a project than I thought.

Dear Greg,

May this find you well. The alternator belt connects the crank pulley (aka the harmonic balancer) and the alternator pulley. You will need to remove the airconditioning belt - the outer-most one - to be able to install the alternator belt. Only one belt drives two accessories, and that belt serves the water pump and the power steering motor, which are on the left side of the engine block (as you face it).

To install a new alternator belt, you need not remove anything. You do need to loosen the air conditioning compressor mounting bolts. You will need to loosen the alternator mounting bolts. Loosening these bolts - and easing the tensioners - will allow you to rotate these motors, so that you can remove and/or put on the belts.

Remove the air conditioning compressor belt. Then, install the alternator belt. Tension it so that the belt has about 1/4" of "drop", when you press a finger on it. Inspect the air conditioning compressor belt closely. If there any cracks in it, replace it.

Hope this helps.

Yours faithfully,

spook

Many thanks for the advice, Spook!

I will tackle this tonight. I already figured out how to loosen the alternator mounting, so it shouldn't be too hard figuring out the A/C compressor...it's obvious that the bolts are harder to reach, though.

I'll let you know how I make out fumbling around in there!

--G.

That's not a normal time for the belt to break. I've run belts for 100K without any breaking although that was way too long. Maybe the belt was defective or perhaps the rubber mounting bushings on the alternator have softened letting the alternator pulley and the crank pulley get out of line. This would increse wear. I've replaced many of these bushings. Last possibility was that it was a cheap belt.

That is an exceptionally low mileage for a '94.

Greg
I had an alternator belt break on my 1994 940GL at 155,000km, and yes, all the lights on the dashpanel came on, plus the motor idled really roughly.

One thought - given you have to go to the trouble of removing the AC belt to replace the alternator belt, why not go the whole hog and remove the waterpump belt as well and replace all 3 belts with new ones. This means you don't have to look at belts again for many miles (apart from routine retensioning). If one has failed, the others may not be far behind... Murphy's law dictates that the waterpump belt fails next, which means having to remove the alternator and AC belts you just replaced...

I used Gates brand belts - got the sizes from their website. The waterpump and AC belts I've kept as spares.

One point to note: do NOT use the long skinny adjuster bolts to adjust belt tension UNLESS you have loosened the pivot points on the relevant item eg. alternator, AC compressor. I've seen many of these bolts snapped by people who just wound then up without loosening the pivot points.

Those ratcheting ring spanners (eg Powerbuilt brand) are really useful for loosening and tightening pivot bolts.

John Marshall
1994 940GL
Christchurch NZ