Intermittent but persistent squeal. (Solved: AC Compressor)

[team_ream]

This squealing issue seems to differ a bit from wha I read about loose/worn alternator belts, in that t only happens occasionally, on startup, and I can't seem to identify any condition that causes it. It's quite a loud squeal and it doesn't subside after the car is warm or starts driving. If I allow it to persist, it smokes. Sometimes, after a few attempts at starting, it magically disappears. Other times, I need to walk away and come back later and it will show no symptoms. It might be worth mentioning that the van recently sat for 30 days while I was traveling. It may have happened once or twice before that, but now it seems to happen a few times per week. Most of what I read indicates the need to tighten or replace the alternator belt, but the inconsistent nature of this problem makes me wonder. Any insight you all might have is much appreciated. Thanks!

[Growlerbearnz]

Your classic startup alternator belt squeal is caused by loose/worn belts being unable to drive the heavily-loaded alternator, which is trying to make as much power as it can because the glow plugs have taken a toll on the battery. If everything is working as it should, it goes away after a minute or two or at higher revs (when the alternator can make the same power while putting less load on the belts). How long it squeals for depends on how hard the glow plugs were working, how drained the battery was before starting, if it's a humid day (wet belts squeal more easily), and how powerful your alternator is- so it can be variable, but...

...and it doesn't subside after the car is warm or starts driving.

That's the bit that's not right. It makes me wonder if your battery is failing (maybe being parked for 30 days finished it off) or there's corrosion on some of the contacts in the battery compartment (that black box full of fusible links can be troublesome)- either of those things would cause your alternator to think the battery needed more power than is reasonable, and would be inconsistent.

If I allow it to persist, it smokes.

Um. From the exhaust, I hope, not from the engine bay? Engine bay smoke would be your belts trying to catch on fire. Exhaust smoke... glow plugs not getting hot enough, maybe? You're using the idle control knob to set your idle speed at 1200rpm until the engine warms up a bit, right? (If not, do. Anything below 700rpm is not good for the engine.)

[team_ream]

As usual, Thanks Growlerbearnz!

As for the smoke - yes, from the engine bay as well as more than usual black smoke from the exhaust (it typically produces the occasional
puff if I accelerate too fast). I haven't driven more than a half block like that bc the van just sounds so awful.

This also brings to mind one other time I remember before the aforementioned 30 day sitting period, when i had some sparks coming from my exhaust on a long drive. I pulled over and had a bit of smoking from the engine bay and the squeal on the subsequent start. It subsided quickly and hasn't sparked from exhaust again (that i know of), but the squealing has become increasingly common.

[Growlerbearnz]

Ok, smoke from the engine bay is not good. The alternator thinks you need way more power than you should, and is shredding the belts to make it. I'm presuming you've looked at the belt tension, and they're not ridiculously loose. (From underneath, you should be able to deflect the belts by about 10mm when pushing with your thumb).

Check the battery (a new one can't hurt), clean up all of the connections in the battery box with a wire brush and deoxit or similar electrical cleaner (disassemble the black plastic fuse holder to clean everything in there too), and clean the connections on the alternator too.

If it doesn't improve, check the voltage at the battery and at the alternator while the engine is running. It should be 14.4 with the engine revving. Anything more than 14.5v indicates a fault. If all your connections are good and the alternator is still acting weird, you might need to replace the alternator.

You're going to need new belts for sure. There's a post in the TRL about squealing and which belts to get. (While the belts are off, turn the water pump pulley by hand to make sure it's not seized. It won't be- you would have way more problems if it were- but just in case...)

Sparks from the exhaust is a new one. (You mean from out the tailpipe, right, not from the vicinity of the turbo?) I can't imagine how a diesel could do that, unless the turbo was on fire and , again, you'd have way more issues than a squealing belt. Extremely clogged exhaust system? (Sparks from the front of the exhaust, near the turbo, would be the alternator. And would be a bad sign.)

Oh. The occasional puff of black smoke? You need to wind it out to 4000rpm more often. Just occasionally, bury your foot and keep it there through the gears until you hit 60mph. (Alternately, just use the Treasure Island onramp where anything less isn't an option). It'll clean the loose soot off the valves and stop the occasional belch of black smoke.

[team_ream]

Thanks! Funny you know about that on-ramp. It's the worst!!

WELL, it happened again tonight and popped it open to inspect. You'll have to excuse my ignorance (i really am not mechanially inclined enough to own such a vehicle), but the pulley closest to the ground and the passenger side door was not spinning. Embarrassed to not know what that is, but happy to learn more with every issue my van has. I've attached a photo and in it you can see some rubber shreds stuck inside the engine bay.

With tonight's incident, I tried to start the van a few times and it continued to scream, so i tried my usual fix - come back in 15 minutes (usually works). This time it started to squeal again and I quickly flicked the key off then back on and it magically started working. WTF????

Also, the cover on the front of that thing is quite wobbly.

Hopefully this photo will be the key to an accurate diagnosis and I can move forward with the repair. Thanks!

IMG_3029.JPG (575.64 KiB) Viewed 7936 times

[Growlerbearnz]

Now I'm going to have to be careful. It looks like I've jumped to the wrong conclusion already, and I don't want to do it again. Being wrong twice in one year would be intolerable

That's your air conditioner compressor. When your AC is off, the little plate on the front shouldn't turn. The pulley the belt rests in obviously *should* turn whenever the engine's running. So you're saying the pulley wasn't turning, and the belt was being dragged around a stuck pulley? (from the shredded-belt splatter on the engine bay walls that's what it looks like...)

If that's the case, take scissors (or a knife) and cut that belt off (it's ruined anyway, and only runs the AC so you won't lose anything else). Also turn off the AC switch, just for luck. That'll solve the problem until you can have the AC pump rebuilt. It looks like the bearings in the front have failed, and it's jammed. Keep the cut belt so you can match the length when it's time to replace it.

The AC compressor is a very common model that was fitted to many Japanese vehicles, not just Mitsubishis. Any AC shop should have no trouble rebuilding it or even finding a replacement. If they freak out at the thought of working on a Japanese import, tell the AC shop it's a Mitsubishi Van/Wagon, just with lots of cool Japanese accessories. Because it practically is.

[Growlerbearnz]

Thanks! Funny you know about that on-ramp. It's the worst!!

I have friends who live on Treasure Island. They used to have a VW, now they have a Tesla- using that onramp has gone from terrifying to *fun*.

[team_ream]

Well that would explain why my AC quit this summer! Glad to know there's an easy temporary fix, as I'm in LA for a few weeks where you NEED a car. A car with AC would be nice, but I'll survive. Gonna cut that sucker off now and head to the beach!

Thanks Growler for your indispensable knowledge and the generosity with which you share it. Please be safe on all your adventures. Us mortals need you!

[team_ream]

Hi again! So I've acquired the compressor, but apparently need the dryer too. I can't seem to find any info on that as far as parts numbers or anything. Does anyone happen to know? Thanks!

[Growlerbearnz]

The AC shop that overhauled mine just fitted a generic, off the shelf dryer. It looked something like this: http://www.ebay.com/itm/New-AC-A-C-Accu ... 0907816359

(but of course I'm not sure that's the exact one they fitted, but it looks close.)

[kombu]

team_ream, do you have the part numbers for the compressor & drier that you used for your repair? I'm trying to track down the parts to repair my AC and the shop says I'll need a new compressor, drier, front & rear expansion valves, and possibly 2 new condensers.

Thanks!