2000 Protege ES AC Fan/Vibration/Intermittent

[gvis]

I'm getting a vibration at idle that only occurs when the AC is on, and not all the time when the AC is on. It intermittently comes and goes, in 5 to 15 second intervals. When it's not making the vibration, the car idles fine and at the right rpm. When the vibration starts, the idle speed jumps a little and I hear a fan like noise.

In all my years working on cars I've never dealt with AC issues, so any kind of fan related issue is new to me. Does one of the small fans in front of the radiator turn on when the thermostat hits a certain open point or the engine a certain temp? If so, shouldn't it maintain a consistent speed and not vibrate?

Searching the net I see references to fan relays, etc, but those appear to be related to the fan swicth inside the car, so I'm confused. Are they related? Is there a separate relay or resistor specific to one of those fans? If so, where is it located and would repacing it solve my issue?

I've sorted out most other rough idle issues recently:

1. Motor mounts. Big difference.
2. Idle Air Control Valve - A new one that fixed the rpm hunting issue I had, AC on or off.
3. EGR Valve - Had a non-cleanable sticking point in the middle of its travel (tried cleaning but didn't work), so a new one resolved the low idle speed issue I had.
4. Exhaust/Converter/Oxygen Sensors - Clogged exhaust overheated the cat. New exhaust and cat. Replaced the sensors because it's recommended and there's 97k miles on the car. Didn't seem to affect idle as much, but made a big difference in smoothness and acceleration once driving past idle.
5. New spark plus and wires. Minor improvement.

Thanks a bunch.

[gvis]

I finally found a thread covering my exact issue and car. Looks like I may have an under or over charge situation. If over charge, maybe it's related to a recharge I had done when I first bought the car at 60k miles (97k now), at which time the ac temp inside the car was below normal.

It sounds like the fans are doing what they are supposed to and that an under or over charge could cause the frequent cycling. But given that I also have the bad vibration, maybe it's leaning toward over charge, based on the thread.

Beyond my abilities, so I may just have the garage I go to check it out (not the same ones who recharged it).

http://www.mazdaforum.com/forum/mazda-protege-23/some-protege-cooling-fan-questions-4001/

[D323]

This vibration you describe, first and foremost, do the engine RPM's change when vibration occurs (up or down from the norm?)
Does the vibration feel like engine related (whole car vibrates?) or more like something vibrating under the hood making noise?
When the AC clutch is engaged can you see the clutch on the face of the AC compressor engage and start to spin (no slipping/slowing down)?


Under charge will cause the AC compressor to cycle frequently, which sounds like what you are describing. If the AC compressor is going out internally or has a failing clutch/ or plate that could cause the engine to bog down when engaged. From the factory the PCM is supposed to kick the engine idle up an additional ~100 rpms or so to aid in the additional force needed to turn the AC compressor. Now if the compressor were to be failing internally or something then the engine could bog down and cause a vibration. Really the best thing would be to get a pressure reading from the low/hi side ports to see what is going on in the system.

Like the other website thread you posted, the relays are switched on by the PCM. If they are kicking on and off again replacing the relay's is useless as they are working properly.

Good luck, hopefully its an easy fix.

[gvis]

Thanks for the info D323! The vibration is much less now, because I spent some time checking all the nuts I had affected and found the passenger side motor mount 14mm bolts were loose. Overall, due to all the fixes, the vibration is gone in all situations except when the AC and the fans are on, but it really is much much less; barely noticeable. But the off/on cycling is noticeable, now more so because the fans are now the dominant noise.

The engine's rpm due increase around 100 when the now slight vibration occurs. If it's an under charge, would that be due to a small leak? The AC temp was low when I bought it about at 60k miles, at which time I had it recharged. At 97k and 6 years later the temp is still the same, and I'm pretty sure the cycling issue has been there all along. Maybe the recharge was just enough to reach the right temp at the vent but is still not fully charged.

I've decided to keep the car another 8 years/75k miles, since I've replaced nearly everything (aside from listed in this thread: radiator, water pump, alternator, rear hubs, one front axle, brakes, master cylinder, struts, control arms, tie rods, sway bar links, new alloy rims, new tires) and will soon get a quality paint job.

That said, what would be the best course for the AC? Bring it in and have checked out or ride it out until either any leak that exists gets worse or the compressor fails and just replace everything then? I'm typically proactive, but back in 2006 it was a bad time fo me to deal with an expensive ac repair so I just took a chance with a recharge.

[MazdaNoob]

6 years on a recharge is awesome ... Freon/r134 doesn't get used up .. it leaks simple as that . when they did the recharge they may have added a leak-stop to the system .

for now simply check the pressures high/low that will indicate whether there is a loss again . if so i would add a dye to the system and spot the fault

[gvis]

Thanks mazdanoob, I think I will go ahead and have that done. I'm pretty sure the first recharge didn't include a stop leak because I had suspected at that time that, based on the how the charge nipple and area around it looked, that the previous owner may have used one of those auto store recharges, which I'd read at the time was a bad thing that could actually harm the system, or stop leak, which I wanted cleared from the system.

I asked the garage to just remove it all and add all new. I didn't ask for any leak checks or leak stop added. I'd already had the timing belt, alt, and water pump done at that time and was out of cash to deal with ac issues. Not ideal, I know, but all I could do at that time. I figured I'd at least get a few years of cooler air and could deal with system issues later. I was pleased to get 6 years.

After all the recent work, the car is running better than when I got it, and it's never leaked oil or tranny fluid (had tranny flush & filter change done at 65k), or shown signs of compression or head gasket issues, so I'm hoping I can get a few years of trouble free driving.

[MazdaNoob]

you've just called on the car gods to jinx you LOL

[gvis]

lol...yeah, I know. But I've worked my ass off to save money fixing this car by doing most of the work myself, so I hope the car gods are kind to me.

In the end I'm coming out much better than buying a new car. It ain't worth much now, given the trashed paint, due to my Peruvian step son's poor snow removal techniques (not much snow in Peru, so he didn't know what he was doing). Wasn't in great shape to begin with, but he put enough deep scrapes into it (all over) to put it over the edge.

Because of how much I'll save in the end, even with a $3k paint job, I've decided to run it to the ground. It's my daily driver now (was my wife's car before we switched and she took the 2001 Durango to better protect our young daughter), and, despite my position at my company, I don't car anymore what I drive (as long as the paint looks decent).

I've got an 04 s2000 I bought new when I was single and with only 30k miles on it now; never driven in the rain or lived outside a garage. That's my baby and what I think of while I commute in a car that's saving me a lot of dough in the end. Marriage and kids soon after changed everything...lol.

But the protege is actually starting to grow on me. Handles pretty well, and now accelerates a lot better. Great as urban assault vehicle in city traffic. I like the low window lines. Seems most economy cars nowadays have high hood lines with rising lines as you go to the back. Like sitting in a tub with less rear visability. i like the immediacy of the protege.

I went with fuel economy replacement tires instead of stock summer performance. Went with Michelin Defenders 185/60/15, vs 195/55/15 that they don't come in. Leans a bit more in the corners due to the softer side wall and less tread, but I can live with that if my mileage improves. New wheel/tire combo is definitely lighter than what I was running.

Keeping my fingers crossed..

[nspznspz]

i have a 2002 protege es and when i turn just the fan on the ac clutch kick on and off when a/c button is off and bog down the engine but once i turn off the fan the engine doesn’t bog down I’m thinking it’s the compressor just wondering if it sounds like it to other ppl on here thanks