Ok, so my "new" (rebuilt) Delco 94 amp alternator gives up the ghost after less than 3 months. After pulling it out, I can see why. The entire cooling fan assembly on the front was gone. Apparently something didn't have enough clearance and obliterated the fan, thus overheating the diodes...which, on examination, I find that one of the three is bad.

So, looking towards the future, I now have another Delco 94 amp to replace it. And, I will be very careful about clearances.

But just wondering...Palm mentions relocation the diode pack to a cooler place. Sounds like a great idea, but where is the "cooler place"??? The alternator is about the lowest thing in the engine bay, and I'm not seeing where elevating it (even with a small fan blowing on it) would help much, given that I'd just be blowing hotter air on it.

This issue is doubly-important for me since I've mounted a Sanden A/C compressor where the air pump use to be. Removing the alternator involves recovering the refrigerant and many other things I'd like to avoid having to do again.

Has anyone relocated their diode pack?

Thanks,

John
1987 XJ-S V12
64,000 miles

 

The diodes are *inside* the alternator. I don't see how they can be moved to a different location.....but if there's a will, there's a way, I reckon.

I recall ....vaguely...some 90s vintage GM cars with alternator cooling ducts. Might have been a TSB retro-fit thing in an effort to address the chronic failures. Might be worth some Googling?

Cheers
DD

 

I went ahead and pulled the old alternator apart, and can now see where it would be fairly easy to relocate the diode pack. See pictures.

Looks like it would just be a matter of running the connections from the diode pack out through the cooling vent holes to wherever the diode was to be relocated. Again, just don't know where in the engine bay would be any cooler.

Of more concern is why the plastic fan assembly self-destructed. I really didn't see any obvious contact points when I removed it, and the new one seems to have plenty of clearance too.

At this point I'll just assume it was a freak failure, or that it was cracked when I put it on.

Thanks,

John
1987 XJ-S V12
64,000 miles

 

My alt on my 86 is UP HIGH on the right side, GM ALT, it's where I think the smog pump should be (I'm guessing because the smog pump was long gone before I got the car)

 

Yep, sounds like someone rightly ditched the air pump on yours and hung an alternator there. I would have done that (makes accessing the alt much easier) but I ended-up hanging the A/C compressor (not the stock one) from the air pump bracket.

I thought about hanging the A/C compressor from the alternator bracket, but no room!

Does your cat have the stock A/C, the big black GM compressor?

Thanks,

John

 

Yes it does on top/middle of the Vee