Yesterday my girlfriend was driving her 626 all day without any issues. It was unusually hot for the past couple of days so she was driving around with the A/C on. She had no issues with the A/C or keeping the engine on. Everything has been running smooth.

She has mentioned before that when she engaged the A/C clutch that instead of the normal, natural dip in RPMs the engine does when the added accessory becomes driven by the engine, it's a little more than the usual dip.

A strong cold front came through this morning so I went outside to start the car and warm it up. The compressor was still engaged from yesterday. I went to start the car and it hardly wanted to turn over, like the starter couldn't keep the engine turning enough to turn on/stay on, and it died. I tried again and I heard a knocking sound at random intervals. I thought, "no way the timing belt has already broken." However, she insisted I disengage the compressor clutch... and whaddaya know: the car started up and stayed on no problem. She drove the rest of the way without turning anything on and she said the car made it to work driving smoothly, no problem.

I want to see if your opinions are the same as mine: I'm assuming the inner bearings have gone to hell on the compressor and it's causing the pulley to stop turning and resist the engine's power to turn the belt against it and now we need to replace the compressor with a new compressor. Yes or no? Opinions?

 

> ... and it's causing the pulley to stop turning and resist the engine's power
> to turn the belt against it and ...

Not knowing much about the A/C of the 626 models ( I just see traces of it in my engine compartment as this functionality is missing in the car, and I have 4 cyl engine ). Just a though:
- Would it be possible to remove the belt driving the A/C and try turning the pulley by hand and feel if there is high resistance?
If the belt driving the A/C has no horizontal ribs like the timing belt, then the pulley must be possible to turn without large resistance or the belt would just slide on the wheel. Notice any strange sound or uneven movements as well.
I cannot imagine that a belt with vertical ribs would run on a pulley with high resistance, it is then pure bad design...

My Mazda have two belts, both have ribs vertical ribs with grooves running around the whole belt. The innermost belt is for the water pump and the generator (at the back of the engine compartment). The second belt is outermost on the crank wheel and runs the power steering pump. I think this is the one which also runs A/C on a 2.0I 16V engine?
Assuming it is similar on a V6, then it wouldn't be too hard to remove the belt? Remove right front wheel, inner plastic cover, loose tension of power steering and then remove belt?
The equipment involved would then be a jack, for safety a jack stand as well and a good set of socket wrenches (size 10, 12, 13 and 14 seems to be very useful).

 

Well, here's an update. When she left work yesterday, again, no problem with the compressor disengaged. When she got home she figured she would give it a try again and it started up and ran just fine with or without the clutch engaged. Weird.

So this morning I went to do the same thing and she went outside with me to observe. This time we automatically made sure the clutch was disengaged (we actually disengaged it last night before we shut the car off) and went to start the car. No knocking or anything, but it had a minor bit of trouble. Instead of starting with the usual "chicka-chicka-chicka-chicka-WHOM!" (the cranks plus engine start) it did this crankless whine without the chicka-chicka effect for about a second, and then it cranked and turned on. (did my sound effects make any sense? Lol)

Any idea? It did a shorter version of this yesterday too. Also worth mentioning that it has done this only in the morning during the coldest part of the day ever since we got a cold front in on Thursday night.